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	<title>Unreal Blog &#187; physics</title>
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		<title>Bye Bye Einstein</title>
		<link>http://www.thulasidas.com/2012-01/bye-bye-einstein.htm</link>
		<comments>http://www.thulasidas.com/2012-01/bye-bye-einstein.htm#comments</comments>
		<pubDate>Tue, 24 Jan 2012 22:43:53 +0000</pubDate>
		<dc:creator>Manoj</dc:creator>
				<category><![CDATA[philosophy]]></category>
		<category><![CDATA[physics]]></category>
		<category><![CDATA[Quotes]]></category>
		<category><![CDATA[Science]]></category>
		<category><![CDATA[Albert Einstein]]></category>
		<category><![CDATA[relativity]]></category>
		<category><![CDATA[Richard Feynman]]></category>
		<category><![CDATA[Untitled]]></category>

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		<description><![CDATA[This last post in the series explains why I believe it is time to say goodbye to Einstein, and why I look forward to how our worldview develops in the light of this CERN discovery of material superluminality. <a href="http://www.thulasidas.com/2012-01/bye-bye-einstein.htm">Continue reading <span class="meta-nav">&#8594;</span></a>]]></description>
			<content:encoded><![CDATA[<p>Starting from his miraculous year of 1905, Einstein has dominated physics with his astonishing insights on space and time, and on mass and gravity. True, there have been other physicists who, with their own brilliance, have shaped and moved modern physics in directions that even Einstein couldn&#8217;t have foreseen; and I don&#8217;t mean to trivialize neither their intellectual achievements nor our giant leaps in physics and technology. But all of modern physics, even the bizarre reality of quantum mechanics, which Einstein himself couldn&#8217;t quite come to terms with, is built on his insights. It is on his shoulders that those who came after him stood for over a century now.</p>
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<i>&#8220;Science alone of all the subjects contains within itself the lesson of the danger of belief in the infallibility of the greatest teachers in the preceding generation. Learn from science that you must doubt the experts. As a matter of fact, I can also define science another way: Science is the belief in the ignorance of experts.&#8221;</i>
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<td align="right">&#8212; Richard Feynman</td>
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<p>One of the brighter ones among those who came after Einstein cautioned us to guard against our blind faith in the infallibility of old masters. Taking my cue from that insight, I, for one, think that Einstein&#8217;s century is behind us now. I know, coming from a non-practicing physicist, who sold his soul to the finance industry, this declaration sounds crazy. Delusional even. But I do have my reasons to see Einstein&#8217;s ideas go.</p>
<p><img src="http://www.thulasidas.com/img/grb-small.gif" alt="[animation]" class="alignleft" />Let&#8217;s start with this picture of a dot flying along a straight line (on the ceiling, so to speak). You are standing at the centre of the line in the bottom (on the floor, that is). If the dot was moving faster than light, how would you see it? Well, you wouldn&#8217;t see anything at all until the first ray of light from the dot reaches you. As the animation shows, the first ray will reach you when the dot is somewhere almost directly above you. The next rays you would see actually come from two different points in the line of flight of the dot &#8212; one before the first point, and one after. Thus, the way you would see it is, incredible as it may seem to you at first, as one dot appearing out of nowhere and then splitting and moving rather symmetrically away from that point. (It is just that the dot is flying so fast that by the time you get to see it, it is already gone past you, and the rays from both behind and ahead reach you at the same instant in time.Hope that statement makes it clearer, rather than more confusing.).</p>
<p><img src="http://www.thulasidas.com/img/ijmpd-figure3.png" alt="[animation]" class="alignright" />Why did I start with this animation of how the illusion of a symmetric object can happen? Well, we see a lot of active symmetric structures in the universe. For instance, look at this picture of Cygnus A. There is a &#8220;core&#8221; from which seem to emanate &#8220;features&#8221; that float away to the &#8220;lobes.&#8221; Doesn&#8217;t it look remarkably similar to what we would see based on the animation above? There are other examples in which some feature points or knots seem to move away from the core where they first appear at. We could come up with a clever model based on superluminality and how it would create illusionary symmetric objects in the heavens. We could, but nobody would believe us &#8212; because of Einstein. I know this &#8212; I tried to get my old physicist friends to consider this model. The response is always some variant of this, &#8220;Interesting, but it cannot work. It violates Lorentz invariance, doesn&#8217;t it?&#8221; LV being physics talk for Einstein&#8217;s insistence that nothing should go faster than light. Now that neutrinos can violate LV, why not me?</p>
<p>Of course, if it was only a qualitative agreement between symmetric shapes and superluminal celestial objects, my physics friends are right in ignoring me. There is much more. The lobes in Cygnus A, for instance, emit radiation in the radio frequency range. In fact, the sky as seen from a radio telescope looks materially different from what we see from an optical telescope. I could show that the spectral evolution of the radiation from this superluminal object fitted nicely with AGNs and another class of astrophysical phenomena, hitherto considered unrelated, called gamma ray bursts. In fact, I managed to publish this model a while ago under the title, &#8220;<a href="http://www.thulasidas.com/2008-11/are-radio-sources-and-gamma-ray-bursts-luminal-booms.htm" title="Superluminality in Astrophysics">Are Radio Sources and Gamma Ray Bursts Luminal Booms?</a>&#8220;.</p>
<p>You see, I need superluminality. Einstein being wrong is a pre-requisite of my being right. So it is the most respected scientist ever vs. yours faithfully, a blogger of the unreal kind. You do the math. <img src='http://www.thulasidas.com/wp-includes/images/smilies/icon_smile.gif' alt=':-)' class='wp-smiley' /> </p>
<p>Such long odds, however, have never discouraged me, and I always rush in where the wiser angels fear to tread. So let me point out a couple of inconsistencies in SR. The derivation of the theory starts off by pointing out the effects of light travel time in time measurements. And later on in the theory, the distortions due to light travel time effects become part of the properties of space and time. (In fact, light travel time effects will make it impossible to have a superluminal dot on a ceiling, as in my animation above &#8212; not even a virtual one, where you take a laser pointer and turn it fast enough that the laser dot on the ceiling would move faster than light. It won&#8217;t.) But, as the theory is understood and practiced now, the light travel time effects are to be applied on top of the space and time distortions (which were due to the light travel time effects to begin with)! Physicists turn a blind eye to this glaring inconstancy because SR &#8220;works&#8221; &#8212; as I made very clear in my previous post in this series.</p>
<p>Another philosophical problem with the theory is that it is not testable. I know, I alluded to a large body of proof in its favor, but fundamentally, the special theory of relativity makes predictions about a uniformly moving frame of reference in the absence of gravity. There is no such thing. Even if there was, in order to verify the predictions (that a moving clock runs slower as in the twin paradox, for instance), you have to have acceleration somewhere in the verification process. Two clocks will have to come back to the same point to compare time. The moment you do that, at least one of the clocks has accelerated, and the proponents of the theory would say, &#8220;Ah, there is no problem here, the symmetry between the clocks is broken because of the acceleration.&#8221; People have argued back and forth about such thought experiments for an entire century, so I don&#8217;t want to get into it. I just want to point out that theory by itself is untestable, which should also mean that it is unprovable. Now that there is direct experimental evidence against the theory, may be people will take a closer look at these inconsistencies and decide that it is time to say bye-bye to Einstein.</p>
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		<title>Why not Discard Special Relativity?</title>
		<link>http://www.thulasidas.com/2012-01/why-not-discard-special-relativity.htm</link>
		<comments>http://www.thulasidas.com/2012-01/why-not-discard-special-relativity.htm#comments</comments>
		<pubDate>Tue, 17 Jan 2012 23:28:42 +0000</pubDate>
		<dc:creator>Manoj</dc:creator>
				<category><![CDATA[philosophy]]></category>
		<category><![CDATA[physics]]></category>
		<category><![CDATA[Science]]></category>
		<category><![CDATA[Albert Einstein]]></category>
		<category><![CDATA[CERN]]></category>
		<category><![CDATA[Maxwells Equations]]></category>
		<category><![CDATA[relativity]]></category>
		<category><![CDATA[Richard Feynman]]></category>

		<guid isPermaLink="false">http://www.thulasidas.com/?p=2190</guid>
		<description><![CDATA[<p>This second post in my series on the superluminality observed (or suspected) at CERN looks at why we cannot accept it.</p> <a href="http://www.thulasidas.com/2012-01/why-not-discard-special-relativity.htm">Continue reading <span class="meta-nav">&#8594;</span></a>]]></description>
			<content:encoded><![CDATA[<p>Nothing would satisfy my anarchical mind more than to see the Special Theory of Relativity (SR) come tumbling down. In fact, I believe that there are compelling reasons to consider SR inaccurate, if not actually wrong, although the physics community would have none of that. I will list my misgivings vis-a-vis SR and present my case against it as the last post in this series, but in this one, I would like to explore why it is so difficult to toss SR out the window.</p>
<p>The special theory of relativity is an extremely well-tested theory. Despite my personal reservations about it, the body of proof for the validity of SR is really enormous and the theory has stood the test of time &#8212; at least so far. But it is the integration of SR into the rest of modern physics that makes it all but impossible to write it off as a failed theory. In experimental high energy physics, for instance, we compute the rest mass of a particle as its identifying statistical signature. The way it works is this: in order to discover a heavy particle, you first detect its daughter particles (decay products, that is), measure their energies and momenta, add them up (as &#8220;4-vectors&#8221;), and compute the invariant mass of the system as the modulus of the aggregate energy-momentum vector. In accordance with SR, the invariant mass is the rest mass of the parent particle. You do this for many thousands of times and make a distribution (a &#8220;histogram&#8221;) and detect any statistically significant excess at any mass. Such an excess is the signature of the parent particle at that mass.</p>
<p>Almost every one of the particles in the particle data book that we know and love is detected using some variant of this method. So the whole Standard Model of particle physics is built on SR. In fact, almost all of modern physics (physics of the 20th century) is built on it. On the theory side, in the thirties, Dirac derived a framework to describe electrons. It combined SR and quantum mechanics in an elegant framework and predicted the existence of positrons, which bore out later on. Although considered incomplete because of its lack of sound physical backdrop, this &#8220;second quantization&#8221; and its subsequent experimental verification can be rightly seen as evidence for the rightness of SR.</p>
<p>Feynman took it further and completed the quantum electrodynamics (QED), which has been the most rigorously tested theory ever. To digress a bit, Feynman was once being shown around at CERN, and the guide (probably a prominent physicist himself) was explaining the experiments, their objectives etc. Then the guide suddenly remembered who he was talking to; after all, most of the CERN experiments were based on Feynman&#8217;s QED. Embarrassed, he said, &#8220;Of course, Dr. Feynman, you know all this. These are all to verify your predictions.&#8221; Feynman quipped, &#8220;Why, you don&#8217;t trust me?!&#8221; To get back to my point and reiterate it, the whole edifice of the standard model of particle physics is built on top of SR. Its success alone is enough to make it impossible for modern physics to discard SR.</p>
<p>So, if you take away SR, you don&#8217;t have the Standard Model and QED, and you don&#8217;t know how accelerator experiments and nuclear bombs work. The fact that they do is proof enough for the validity of SR, because the alternative (that we managed to build all these things without really knowing how they work) is just too weird. It&#8217;s not just the exotic (nuclear weaponry and CERN experiments), but the mundane that should convince us. Fluorescent lighting, laser pointers, LED, computers, mobile phones, GPS navigators, iPads &#8212; in short, all of modern technology is, in some way, a confirmation of SR.</p>
<p>So the OPERA result on observed superluminalily has to be wrong. But I would like it to be right. And I will explain why in my next post. Why everything we accept as a verification of SR could be a case of mass delusion &#8212; almost literally. Stay tuned!</p>
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		<title>Faster than Light</title>
		<link>http://www.thulasidas.com/2012-01/faster-than-light.htm</link>
		<comments>http://www.thulasidas.com/2012-01/faster-than-light.htm#comments</comments>
		<pubDate>Mon, 09 Jan 2012 23:11:36 +0000</pubDate>
		<dc:creator>Manoj</dc:creator>
				<category><![CDATA[philosophy]]></category>
		<category><![CDATA[physics]]></category>
		<category><![CDATA[Science]]></category>
		<category><![CDATA[Albert Einstein]]></category>
		<category><![CDATA[Maxwells Equations]]></category>

		<guid isPermaLink="false">http://www.thulasidas.com/?p=2157</guid>
		<description><![CDATA[<p>When they discovered particles going faster than light at CERN, they didn't want to believe themselves. They were practically begging the rest of the community to find a mistake in this discovery. Why would they do that? This post and its follow ups will try to shed some light on this strange lack of faith.</p> <a href="http://www.thulasidas.com/2012-01/faster-than-light.htm">Continue reading <span class="meta-nav">&#8594;</span></a>]]></description>
			<content:encoded><![CDATA[<p>CERN has <a href="http://arxiv.org/abs/1109.4897">published news</a> about some subatomic particles exceeding the speed of light, according to <a href="http://www.bbc.co.uk/news/science-environment-15017484">BBC</a> and other sources. If confirmed true, this will remove the linchpin of modern physics &#8212; it is hard to overstate how revolutionary this discovery would be to our collective understanding of world we live in, from finest structure of matter to the time evolution of the cosmos. My own anarchical mind revels at the thought of all of modern physics getting rewritten, but I also have a much more personal stake in this story. I will get to it later in this series of posts. First, I want to describe the backdrop of thought that led to the notion that the speed of light could not be breached. The soundness of that scientific backdrop (if not the actual conclusion about the inviolability of light-speed) makes it very difficult to forgo the intellectual achievements of the past one hundred years in physics, which is what we will be doing once we confirm this result. In my second post, I will list what these intellectual achievements are, and how drastically their form will have to change. The scientists who discovered the speed violation, of course, understand this only too well, which is why they are practically begging the rest of the physics community to find a mistake in this discovery of theirs. As it often happens in physics, if you look for something hard enough, you are sure to find it &#8212; this is the experimental bias that all experimental physicists worth their salt are aware of and battle against. I hope a false negation doesn&#8217;t happen, for, as I will describe in my third post in this series, if confirmed, this speed violation is of <a href="http://www.thulasidas.com/2008-11/are-radio-sources-and-gamma-ray-bursts-luminal-booms.htm" title="Superluminality in Astrophysics">tremendous personal importance</a> to me.</p>
<p>The constancy (and the resultant inviolability) of the speed of light, of course, comes from Einstein&#8217;s Special Theory of Relativity, or SR. This theory is an extension of a simple idea. In fact, Einstein&#8217;s genius is in his ability to carry a simple idea to its logically inevitable, albeit counter-intuitive (to the point of being illogical!) conclusion. In the case of SR, he picks an idea so obvious &#8212; that the laws of physics should be independent of the state of motion. If you are in a train going at a constant speed, for instance, you can&#8217;t tell whether you are moving or not (if you close the windows, that is). The statement &#8220;You can&#8217;t tell&#8221; can be recast in physics as, &#8220;There is no experiment you can device to detect your state of motion.&#8221; This should be obvious, right? After all, if the laws kept changing every time you moved about, it is as good as having no laws at all.</p>
<p>Then came Maxwell. He wrote down the equations of electricity and magnetism, thereby elegantly unifying them. The equations state, using fancy vector notations, that a changing magnetic field will create an electric field, and a changing electric field will create a magnetic field, which is roughly how a car alternator and an electric motor work. These elegant equations have a wave solution.</p>
<p>The existence of a wave solution is no surprise, since a changing electric field generates a magnetic field, which in turn generates an electric field, which generates a magnetic filed and so on ad infinitum. What is surprising is the fact that the speed of propagation of this wave predicted by Maxwell&#8217;s equations is <i>c</i>, the speed of light. So it was natural to suppose that light was a form of electromagnetic radiation, which means that if you take a magnet and jiggle it fast enough, you will get light moving away from you at <i>c</i> &#8211; if we accept that light is indeed EM wave.</p>
<p>What is infinitely more fundamental is the question whether Maxwell&#8217;s equations are actually laws of physics. It is hard to argue that they aren&#8217;t. Then the follow-up question is whether these equations should obey the axiom that all laws of physics are supposed to obey &#8212; namely they should be independent of the state of motion. Again, hard to see why not. Then how do we modify Maxwell&#8217;s equations such that they are independent of motion? This is the project Einstein took on under the fancy name, &#8220;Covariant formulation of Maxwell&#8217;s equations,&#8221; and published the most famous physics article ever with an even fancier title, &#8220;On the Electrodynamics of Moving Bodies.&#8221; We now call it the Special Theory of Relativity, or SR.</p>
<p>To get a bit technical, Maxwell&#8217;s equations have the space derivatives of electric and magnetic fields relating to the time derivatives of charges and currents. In other words, space and time are related through the equations. And the wave solution to these equations with the propagation speed of <i>c</i> becomes a constraint on the properties of space and time. This is a simple <a href="http://www.thulasidas.com/2008-11/why-the-speed-of-light.htm" title="Why the Speed of light?">philosophical look on SR</a>, more than a physics analysis.</p>
<p>Einstein&#8217;s approach was to employ a series of thought experiments to establish that you needed a light signal to sync clocks and hypothesize that the speed of light had to be constant in all moving frames of reference. In other words, the speed of light is independent of the state of motion, as it has to be if Maxwell&#8217;s equations are to be laws of physics.</p>
<p>This aspect of the theory is supremely counter-intuitive, which is physics lingo to say something is hard to believe. In the case of the speed of light, you take a ray of light, run along with it at a high speed, and measure its speed, you still get <i>c</i>. Run against it and measure it &#8212; still <i>c</i>. To achieve this constancy, Einstein rewrote the equations of velocity addition and subtraction. On consequence of these rewritten equations is that nothing can go faster than light.</p>
<p>This is my long-winded description of the context in which the speed violation measured at OPERA has to be seen. If the violation is confirmed, we have a few unpleasant choices to pick from:</p>
<ol>
<li>Electrodynamics (Maxwell&#8217;s equations) is not invariant under motion.</li>
<li>Light is not really electromagnetic in nature.</li>
<li>SR is not the right covariant formulation of electrodynamics.</li>
</ol>
<p>The first choice is patently unacceptable because it is tantamount to stating that electrodynamics is not physics. A moving motor (e.g., if you take your electric razor on a flight) would behave differently from a static one (you may not be able to shave). The second choice also is quite absurd. In addition to the numeric equality between the speed of the waves from Maxwell&#8217;s equations and the measured value of <i>c</i>, we do have other compelling reasons why we should believe that light is EM waves. Radio waves induce electric signals in an antenna, light knocks of electrons, microwaves can excite water molecules and cook food and so on.</p>
<p>The only real choice we are left with is the last one &#8212; which is to say SR is wrong. Why not discard SR? More reasons than a blog post can summarize, but I&#8217;ll try to summarize them any way in my next post.</p>
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		<title>What is Unreal Blog?</title>
		<link>http://www.thulasidas.com/2011-10/what-is-unreal-blog.htm</link>
		<comments>http://www.thulasidas.com/2011-10/what-is-unreal-blog.htm#comments</comments>
		<pubDate>Mon, 03 Oct 2011 11:37:06 +0000</pubDate>
		<dc:creator>Manoj</dc:creator>
				<category><![CDATA[philosophy]]></category>
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		<category><![CDATA[Topical]]></category>
		<category><![CDATA[cognitive neuroscience]]></category>
		<category><![CDATA[life]]></category>
		<category><![CDATA[philsophy of mind]]></category>
		<category><![CDATA[physical reality]]></category>
		<category><![CDATA[Pirsig]]></category>
		<category><![CDATA[relativity]]></category>
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		<description><![CDATA[<p>This post is an expanded version of a Web interview regarding my blog. It attempts to answer the question why I blog. And why one should take philosophy seriously. Seriously!</p> <a href="http://www.thulasidas.com/2011-10/what-is-unreal-blog.htm">Continue reading <span class="meta-nav">&#8594;</span></a>]]></description>
			<content:encoded><![CDATA[<p><b>Tell us a little about why you started your blog, and what keeps you motivated about it.</b></p>
<p>As my writings started appearing in different magazines and newspapers as <a href="http://www.thulasidas.com/category/columns">regular columns</a>, I wanted to collect them in one place &#8212; as an anthology of the internet kind, as it were. That&#8217;s how my blog was born. The motivation to continue blogging comes from the memory of how my first book, <a href="http://www.amazon.com/exec/obidos/ASIN/9810575947/unrblo-20" target="_blank">The Unreal Universe</a>, took shape out of the random notes I started writing on scrap books. I believe the ideas that cross anybody&#8217;s mind often get forgotten and lost unless they are written down. A blog is a convenient platform to put them down. And, since the blog is rather public, you take some care and effort to express yourself well.</p>
<p><b>Do you have any plans for the blog in the future?</b></p>
<p>I will keep blogging, roughly at the rate of one post a week or so. I don&#8217;t have any big plans for the blog per se, but I do have some other Internet ideas that may spring from my blog.</p>
<p><b>Philosophy is usually seen as a very high concept, intellectual subject. Do you think that it can have a greater impact in the world at large?</b></p>
<p>This is a question that troubled me for a while. And I wrote <a href="http://www.thulasidas.com/2010-01/love-of-wisdom.htm">a post on it</a>, which may answer it to the best of my ability. To repeat myself a bit, philosophy is merely a description of whatever intellectual pursuits that we indulge in. It is just that we don&#8217;t often see it that way. For instance, if you are doing physics, you think that you are quite far removed from philosophy. The philosophical spins that you put on a theory in physics is mostly an afterthought, it is believed. But there are instances where you can actually <i>apply</i> philosophy to solve problems in physics, and come up with new theories. This indeed is the theme of my book, <a href="http://www.amazon.com/exec/obidos/ASIN/9810575947/unrblo-20" target="_blank">The Unreal Universe</a>. It asks the question, if some object flew by faster than the speed of light, <a href="http://theunrealuniverse.com/about/physics/animation-concepts" target="_blank">what would it look like</a>? With the recent discovery that <a href="http://www.bbc.co.uk/news/science-environment-15017484">solid matter does travel faster than light</a>, I feel vindicated and look forward to further developments in physics.</p>
<p><b>Do you think many college students are attracted to philosophy? What would make them choose to major in it?</b></p>
<p>In today&#8217;s world, I am afraid philosophy is supremely irrelevant. So it may be difficult to get our youngsters interested in philosophy. I feel that one can hope to improve its relevance by pointing out the interconnections between whatever it is that we do and the intellectual aspects behind it. Would that make them choose to major in it? In a world driven by excesses, it may not be enough. Then again, it is world where articulation is often mistaken for accomplishments. Perhaps philosophy can help you articulate better, sound really cool and impress that girl you have been after &#8212; to put it crudely.</p>
<p>More seriously, though, what I said about the irrelevance of philosophy can be said about, say, physics as well, despite the fact that it gives you computers and iPads. For instance, when Copernicus came up with the notion that the earth is revolving around the sun rather than the other way round, profound though this revelation was, in what way did it change our daily life? Do you really have to know this piece of information to live your life? This irrelevance of such profound facts and theories bothered scientists like Richard Feynman.</p>
<p><b>What kind of advice or recommendations would you give to someone who is interested in philosophy, and who would like to start learning more about it?</b></p>
<p>I started my path toward philosophy via physics. I think philosophy by itself is too detached from anything else that you cannot really start with it. You have to find your way toward it from whatever your work entails, and then expand from there. At least, that&#8217;s how I did it, and that way made it very real. When you ask yourself a question like <a href="http://www.thulasidas.com/2009-10/half-a-bucket-of-water.htm" target="_blank">what is space</a> (so that you can understand what it means to say that space contracts, for instance), the answers you get are very relevant. They are not some philosophical gibberish. I think similar paths to relevance exist in all fields. See for example how <a href="http://www.thulasidas.com/2008-08/zen-and-the-art-of-motorcycle-maintenance.htm">Pirsig</a> brought out the notion of quality in his work, not as an abstract definition, but as an all-consuming (and eventually dangerous) obsession.</p>
<p>In my view, philosophy is a wrapper around multiple silos of human endeavor. It helps you see the links among seemingly unrelated fields, such as <a href="http://theunrealuniverse.com/space-and-time" target="_blank">cognitive neuroscience and special relativity</a>. Of what practical use is this knowledge, I cannot tell you. Then again, of what practical use is life itself?</p>
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		<title>A Parker Pen from Singapore</title>
		<link>http://www.thulasidas.com/2011-03/a-parker-pen-from-singapore.htm</link>
		<comments>http://www.thulasidas.com/2011-03/a-parker-pen-from-singapore.htm#comments</comments>
		<pubDate>Wed, 16 Mar 2011 23:03:27 +0000</pubDate>
		<dc:creator>Manoj</dc:creator>
				<category><![CDATA[Life and Death]]></category>
		<category><![CDATA[Malayalam]]></category>
		<category><![CDATA[physics]]></category>
		<category><![CDATA[Work and Life]]></category>
		<category><![CDATA[Kerala]]></category>

		<guid isPermaLink="false">http://www.thulasidas.com/?p=1924</guid>
		<description><![CDATA[<p>About a fifty-year old Parker pen that held an important lesson for me.</p> <a href="http://www.thulasidas.com/2011-03/a-parker-pen-from-singapore.htm">Continue reading <span class="meta-nav">&#8594;</span></a>]]></description>
			<content:encoded><![CDATA[<p>During the early part of the last century, there was significant migration of Chinese and Indians to Singapore. Most of the migrants of Indian origin were ethnic Tamils, which is why Tamil is an official language here. But some came from my <a href="http://www.thulasidas.com/category/humor-columns/malayalam" target="_blank">Malayalam</a>-speaking native land of Kerala. Among them was Natarajan who, fifty years later, would share with me his impressions of <a href="http://en.wikipedia.org/wiki/Subhas_Chandra_Bose" target="_blank">Netaji Subhash Chandra Bose</a> and the Indian National Army of the forties. Natarajan would, by then, be called the Singapore Grandpa (Singapore Appuppa), and teach me yoga, explaining the mystical aspects of it a bit, saying things like, &#8220;A practitioner of yoga, even when he is in a crowd, is not quite a part of it.&#8221; I remembered this statement when a friend of mine at work commented that I walked untouched (kind of like Tim Robbins in the Shawshank Redemption) by the corporate hustle and bustle, which, of course, may have been a polite way of calling me lazy.</p>
<p><script type="text/javascript">
  amazon('3DB000P0J0EW') ;
</script></p>
<p>Anyway, the Singapore Grandpa (a cousin to my paternal grandfather) was quite fond of my father, who was among the first University graduates from that part of Kerala. He got him a Parker pen from Singapore as a graduation gift. Some fifteen years later, this pen would teach me a lesson that is still not fully learned four decades on.</p>
<p>My father was rather proud of this pen, its quality and sturdiness, and was bragging to his friends once. &#8220;Even if I wanted to break it, I wouldn&#8217;t be able to!&#8221; he said, without noticing his son (yours faithfully), all of four years then with only a limited understanding of hypothetical conditionals of this kind. Next evening, when he came back from work, I was waiting for him at the door, beaming with pride, holding his precious pen thoroughly crushed. &#8220;Dad, dad, I did it! I managed to break your pen for you!&#8221;</p>
<p>Heart-broken as my father must have been, he didn&#8217;t even raise his voice. He asked, &#8220;What did you do that for, son?&#8221; using the overly affectionate Malayalam word for &#8220;son&#8221;. I was only too eager to explain. &#8220;You said yesterday that you have been trying to break it, but couldn&#8217;t. I did it for you!&#8221; Rather short on language skills, I was already a bit too long on physics. I had placed the pen near the hinges of a door and used the lever action by closing it to accomplish my mission of breaking the pen. In fact, I remembered this incident when I was trying to explain to my wife (short on physics) why the door stopper placed close to the hinges was breaking the floor tiles rather than stopping the door.</p>
<p>My father tried to fix the Parker pen with scotch tape (which was called cellophane tape at that time) and rubber bands. Later, he managed to replace the body of the pen although he could never quite fix the leaking ink. I still have the pen, and this enduring lesson in infinite patience.</p>
<p>Two and half years ago, <a href="http://www.thulasidas.com/2008-10/death-of-a-parent.htm">my father passed away</a>. During the ensuing soul-searching, this close friend of mine remarked, &#8220;Well, now that you know what it takes, how well do you think you are doing?&#8221; I don&#8217;t think I am doing that well, for some lessons, even when fully learned, are just too hard to put in practice.</p>
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		<title>The Unreal Universe</title>
		<link>http://www.thulasidas.com/2010-09/the-unreal-universe.htm</link>
		<comments>http://www.thulasidas.com/2010-09/the-unreal-universe.htm#comments</comments>
		<pubDate>Tue, 28 Sep 2010 22:47:26 +0000</pubDate>
		<dc:creator>Manoj</dc:creator>
				<category><![CDATA[Articles and Essays]]></category>
		<category><![CDATA[Books]]></category>
		<category><![CDATA[Columns]]></category>
		<category><![CDATA[Creative]]></category>
		<category><![CDATA[philosophy]]></category>
		<category><![CDATA[physics]]></category>
		<category><![CDATA[Science]]></category>
		<category><![CDATA[Topical]]></category>
		<category><![CDATA[metaphysics]]></category>
		<category><![CDATA[relativity]]></category>

		<guid isPermaLink="false">http://www.thulasidas.com/?p=1675</guid>
		<description><![CDATA[I recently made my first book available on Amazon. I thought I would post this article, which is a good summary of the book. This article was published in a magazine in Singapore. <a href="http://www.thulasidas.com/2010-09/the-unreal-universe.htm">Continue reading <span class="meta-nav">&#8594;</span></a>]]></description>
			<content:encoded><![CDATA[<p>We know that our universe is a bit unreal. The stars we see in the night sky, for instance, are not really there. They may have moved or even died by the time we get to see them. This delay is due to the time it takes for light from the distant stars and galaxies to reach us. We know of this delay. The sun that we see now is already eight minutes old by the time we see it. This delay is not a big deal; if we want to know what is going on at the sun right now, all we have to do is to wait for eight minutes. We do have to &#8220;correct&#8221; for the delay in our perception due to the finite speed of light before we can trust what we see.</p>
<p>Now, this effect raises an interesting question &#8212; what is the &#8220;real&#8221; thing that we see? If seeing is believing, the stuff that we see should be the real thing. Then again, we know of the light travel time effect. So we should correct what we see before believing it. What then does &#8220;seeing&#8221; mean? When we say we see something, what do we really mean?</p>
<p><script type="text/javascript"><!--
 amazon('B003YRILE8', '[The Unreal Universe]', 'The Unreal Universe -- Kindle Edition for $9.95') ;
//--></script>Seeing involves light, obviously. It is the finite (albeit very high) speed of light influences and distorts the way we see things. This fact should hardly come as a surprise because we do know that there is a delay in seeing objects like stars. What is surprising (and seldom highlighted) is that when it comes to seeing moving objects, we cannot back-calculate the same way we take out the delay in seeing the sun. If we see a celestial body moving at an improbably high speed, we cannot figure out how fast and in what direction it is &#8220;really&#8221; moving without making further assumptions. One way of handling this difficulty is to ascribe the distortions in our perception to the fundamental properties of the arena of physics &#8212; space and time. Another course of action is to accept the disconnection between our perception and the underlying &#8220;reality&#8221; and deal with it in some way.</p>
<p>This disconnect between what we see and what is out there is not unknown to many philosophical schools of thought. Phenomenalism, for instance, holds the view that space and time are not objective realities. They are merely the medium of our perception. All the phenomena that happen in space and time are merely bundles of our perception. In other words, space and time are cognitive constructs arising from perception. Thus, all the physical properties that we ascribe to space and time can only apply to the phenomenal reality (the reality as we sense it). The noumenal reality (which holds the physical causes of our perception), by contrast, remains beyond our cognitive reach.</p>
<p>One, almost accidental, difficulty in redefining the effects of the finite speed of light as the properties of space and time is that any effect that we do understand gets instantly relegated to the realm of optical illusions. For instance, the eight-minute delay in seeing the sun, because we can readily understand it and disassociate it from our perception using simple arithmetic, is considered a mere optical illusion. However, the distortions in our perception of fast moving objects, although originating from the same source are considered a property of space and time because they are more complex. At some point, we have to come to terms with the fact that when it comes to seeing the universe, there is no such thing as an optical illusion, which is probably what Goethe pointed out when he said, &#8220;Optical illusion is optical truth.&#8221;</p>
<p><script type="text/javascript"><!--
 amazon('9810575947', '[The Unreal Universe]', 'The Unreal Universe -- Paperback from Amazon for $15.95') ;
//--></script>The distinction (or lack thereof) between optical illusion and truth is one of the oldest debates in philosophy. After all, it is about the distinction between knowledge and reality. Knowledge is considered our view about something that, in reality, is &#8220;actually the case.&#8221; In other words, knowledge is a reflection, or a mental image of something external. In this picture, the external reality goes through a process of becoming our knowledge, which includes perception, cognitive activities, and the exercise of pure reason. This is the picture that physics has come to accept. While acknowledging that our perception may be imperfect, physics assumes that we can get closer and closer to the external reality through increasingly finer experimentation, and, more importantly, through better theorization. The Special and General Theories of Relativity are examples of brilliant applications of this view of reality where simple physical principles are relentlessly pursued using the formidable machine of pure reason to their logically inevitable conclusions.</p>
<p>But there is another, competing view of knowledge and reality that has been around for a long time. This is the view that regards perceived reality as an internal cognitive representation of our sensory inputs. In this view, knowledge and perceived reality are both internal cognitive constructs, although we have come to think of them as separate. What is external is not the reality as we perceive it, but an unknowable entity giving rise to the physical causes behind sensory inputs. In this school of thought, we build our reality in two, often overlapping, steps. The first step consists of the process of sensing, and the second one is that of cognitive and logical reasoning. We can apply this view of reality and knowledge to science, but in order do so, we have to guess the nature of the absolute reality, unknowable as it is.</p>
<p>The ramifications of these two different philosophical stances described above are tremendous. Since modern physics has embraced a non-phenomenalistic view of space and time, it finds itself at odds with that branch of philosophy. This chasm between philosophy and physics has grown to such a degree that the Nobel prize winning physicist, Steven Weinberg, wondered (in his book &#8220;Dreams of a Final Theory&#8221;) why the contribution from philosophy to physics have been so surprisingly small. It also prompts philosophers to make statements like, &#8220;Whether &#8216;noumenal reality causes phenomenal reality&#8217; or whether &#8216;noumenal reality is independent of our sensing it&#8217; or whether &#8216;we sense noumenal reality,&#8217; the problem remains that the concept of noumenal reality is a totally redundant concept for the analysis of science.&#8221;</p>
<p>From the perspective of cognitive neuroscience, everything we see, sense, feel and think is the result of the neuronal interconnections in our brain and the tiny electrical signals in them. This view must be right. What else is there? All our thoughts and worries, knowledge and beliefs, ego and reality, life and death &#8212; everything is merely neuronal firings in the one and half kilograms of gooey, grey material that we call our brain. There is nothing else. Nothing!</p>
<p>In fact, this view of reality in neuroscience is an exact echo of phenomenalism, which considers everything a bundle of perception or mental constructs. Space and time are also cognitive constructs in our brain, like everything else. They are mental pictures our brains concoct out of the sensory inputs that our senses receive. Generated from our sensory perception and fabricated by our cognitive process, the space-time continuum is the arena of physics. Of all our senses, sight is by far the dominant one. The sensory input to sight is light. In a space created by the brain out of the light falling on our retinas (or on the photo sensors of the Hubble telescope), is it a surprise that nothing can travel faster than light?</p>
<p>This philosophical stance is the basis of my book, <em><a href="http://www.amazon.com/exec/obidos/ASIN/9810575947/unrblo-20">The Unreal Universe</a></em>, which explores the common threads binding physics and philosophy. Such philosophical musings usually get a bad rap from us physicists. To physicists, philosophy is an entirely different field, another silo of knowledge, which holds no relevance to their endeavors. We need to change this belief and appreciate the overlap among different knowledge silos. It is in this overlap that we can expect to find great breakthroughs in human thought.</p>
<p>The twist to this story of light and reality is that we seem to have known all this for a long time. Classical philosophical schools seem to have thought along lines very similar to Einstein&#8217;s reasonings. The role of light in creating our reality or universe is at the heart of Western religious thinking. A universe devoid of light is not simply a world where you have switched off the lights. It is indeed a universe devoid of itself, a universe that doesn&#8217;t exist. It is in this context that we have to understand the wisdom behind the statement that &#8220;the earth was without form, and void&#8221; until God caused light to be, by saying &#8220;Let there be light.&#8221;</p>
<p>The Quran also says, &#8220;Allah is the light of the heavens and the earth,&#8221; which is mirrored in one of the ancient Hindu writings: &#8220;Lead me from darkness to light, lead me from the unreal to the real.&#8221; The role of light in taking us from the unreal void (the nothingness) to a reality was indeed understood for a long, long time. Is it possible that the ancient saints and prophets knew things that we are only now beginning to uncover with all our supposed advances in knowledge?</p>
<p>I know I may be rushing in where angels fear to tread, for reinterpreting the scriptures is a dangerous game. Such alien interpretations are seldom welcome in the theological circles. But I seek refuge in the fact that I am looking for concurrence in the metaphysical views of spiritual philosophies, without diminishing their mystical and theological value.</p>
<p>The parallels between the noumenal-phenomenal distinction in phenomenalism and the <em>Brahman-Maya</em> distinction in <em>Advaita </em>are hard to ignore. This time-tested wisdom on the nature of reality from the repertoire of spirituality is now being reinvented in modern neuroscience, which treats reality as a cognitive representation created by the brain. The brain uses the sensory inputs, memory, consciousness, and even language as ingredients in concocting our sense of reality. This view of reality, however, is something physics is yet to come to terms with. But to the extent that its arena (space and time) is a part of reality, physics is not immune to philosophy.</p>
<p>As we push the boundaries of our knowledge further and further, we are beginning to discover hitherto unsuspected and often surprising interconnections between different branches of human efforts. In the final analysis, how can the diverse domains of our knowledge be independent of each other when all our knowledge resides in our brain? Knowledge is a cognitive representation of our experiences. But then, so is reality; it is a cognitive representation of our sensory inputs. It is a fallacy to think that knowledge is our internal representation of an external reality, and therefore distinct from it. Knowledge and reality are both internal cognitive constructs, although we have come to think of them as separate.</p>
<p>Recognizing and making use of the interconnections among the different domains of human endeavor may be the catalyst for the next breakthrough in our collective wisdom that we have been waiting for.</p>
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		<title>Ghost of Gravity</title>
		<link>http://www.thulasidas.com/2009-11/ghost-of-gravity.htm</link>
		<comments>http://www.thulasidas.com/2009-11/ghost-of-gravity.htm#comments</comments>
		<pubDate>Tue, 17 Nov 2009 00:17:21 +0000</pubDate>
		<dc:creator>Manoj</dc:creator>
				<category><![CDATA[philosophy]]></category>
		<category><![CDATA[physics]]></category>
		<category><![CDATA[gravity]]></category>
		<category><![CDATA[Newton]]></category>
		<category><![CDATA[Pirsig]]></category>
		<category><![CDATA[zen and the art of motorcycle maintenance]]></category>

		<guid isPermaLink="false">http://www.thulasidas.com/?p=1500</guid>
		<description><![CDATA[Some beliefs are superstitions, while some others are scientific theories. What exactly is the difference between them? Let's listen to what Pirsig has to say about it. <a href="http://www.thulasidas.com/2009-11/ghost-of-gravity.htm">Continue reading <span class="meta-nav">&#8594;</span></a>]]></description>
			<content:encoded><![CDATA[<p>It has been a while since my last post. I was reading <em><a href="http://www.thulasidas.com/2008-08/zen-and-the-art-of-motorcycle-maintenance.htm">Zen and the Art of Motorcycle Maintenance</a></em> again just now, and came to the part where Pirsig compares scientific beliefs and superstitions. I thought I would paraphrase it and share it with my readers. But it is perhaps best to borrow his own words: &#8220;The laws of physics and of logic &#8212; the number system &#8212; the principle of algebraic substitution. These are ghosts. We just believe in them so thoroughly they seem real. For example, it seems completely natural to presume that gravitation and the law of gravitation existed before Isaac Newton. It would sound nutty to think that until the seventeenth century there was no gravity. So when did this law start? Has it always existed? What I&#8217;m driving at is the notion that before the beginning of the earth, before the sun and the stars were formed, before the primal generation of anything, the law of gravity existed. Sitting there, having no mass of its own, no energy of its own, not in anyone&#8217;s mind because there wasn&#8217;t anyone, not in space because there was no space either, not anywhere&#8230;this law of gravity still existed? If that law of gravity existed, I honestly don&#8217;t know what a thing has to do to be nonexistent. It seems to me that law of gravity has passed every test of nonexistence there is. You cannot think of a single attribute of nonexistence that that law of gravity didn&#8217;t have. Or a single scientific attribute of existence it did have. And yet it is still &#8216;common sense&#8217; to believe that it existed.</p>
<p>&#8220;Well, I predict that if you think about it long enough you will find yourself going round and round and round and round until you finally reach only one possible, rational, intelligent conclusion. The law of gravity and gravity itself did not exist before Isaac Newton. No other conclusion makes sense.  And what that means is that that law of gravity exists nowhere except in people&#8217;s heads! It&#8217;s a ghost! We are all of us very arrogant and conceited about running down other people&#8217;s ghosts but just as ignorant and barbaric and superstitious about our own.&#8221;</p>
<p>[This quote is from an online version of <em>Zen and the Art of Motorcycle Maintenance</em>.]</p>
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		<title>Only a Matter of Time</title>
		<link>http://www.thulasidas.com/2009-10/only-a-matter-of-time.htm</link>
		<comments>http://www.thulasidas.com/2009-10/only-a-matter-of-time.htm#comments</comments>
		<pubDate>Sat, 10 Oct 2009 00:23:31 +0000</pubDate>
		<dc:creator>Manoj</dc:creator>
				<category><![CDATA[philosophy]]></category>
		<category><![CDATA[physics]]></category>
		<category><![CDATA[Science]]></category>
		<category><![CDATA[space and time]]></category>

		<guid isPermaLink="false">http://www.thulasidas.com/?p=1481</guid>
		<description><![CDATA[Here is an unreal look at the what and why of time. Why do we have a sense of time when none of our five senses can sense it? <a href="http://www.thulasidas.com/2009-10/only-a-matter-of-time.htm">Continue reading <span class="meta-nav">&#8594;</span></a>]]></description>
			<content:encoded><![CDATA[<p>Although we speak of space and time in the same breath, they are quite different in many ways. Space is something we perceive all around us. We see it (rather, objects in it), we can move our hand through it, and we know that if our knee tries to occupy the same space as, say, the coffee table, it is going to hurt. In other words, we have sensory correlates to our notion of space, starting from our most precious sense of sight. </p>
<p>Time, on the other hand, has no direct sensory backing. And for this reason, it becomes quite difficult to get a grip over it. What is time? We sense it indirectly through change and motion. But it would be silly to define time using the concepts of change and motion, because they already include the notion of time. The definition would be cyclic. </p>
<p>Assuming, for now, that no definition is necessary, let&#8217;s try another perhaps more tractable issue. Where does this strong sense of time come from? I once postulated that it comes from our knowledge of our demise &#8212; that questionable gift that we all possess. All the time durations that we are aware of are measured against the yardstick of our lifespan, perhaps not always consciously. I now wonder if this postulate is firm enough, and further ruminations on this issue have convinced me that I am quite ignorant of these things and need more knowledge. Ah.. only if I had more time. <img src='http://www.thulasidas.com/wp-includes/images/smilies/icon_smile.gif' alt=':)' class='wp-smiley' /> </p>
<p>In any case, even this more restricted question of the origin of time doesn&#8217;t seem to be that tractable, after all. Physics has another deep problem with time. It has to do with the directionality. It cannot easily explain why time has a direction &#8212; an arrow, as it were. This arrow does not present itself in the fundamental laws governing physical interactions. All the laws in physics are time reversible. The laws of gravity, electromagnetism or quantum mechanics are all invariant with respect to a time reversal. That is to say, they look the same with time going forward or backward. So they give no clue as to why we experience the arrow of time.</p>
<p>Yet, we know that time, as we experience it, is directional. We can remember the past, but not the future. What we do now can affect the future, but not the past.  If we play a video tape backwards, the sequence of events (like broken pieces of glass coming together to for a vase) will look funny to us. However, if we taped the motion of the planets in a solar system, or the electron cloud in an atom, and played it backward to a physicist, he would not find anything funny in the sequences because the physical laws are reversible.</p>
<p>Physics considers the arrow of time an emergent property of statistical collections. To illustrate this thermodynamic explanation of time, let&#8217;s consider an empty container where we place some dry ice. After some time, we expect to see a uniform distribution of carbon dioxide gas in the container. Once spread out, we do not expect the gas in the container to coagulate into solid dry ice, no matter how long we wait. The video of CO2 spreading uniformly in the container is a natural one. Played backward, the sequence of the CO2  gas in the container congealing to solid dry ice in a corner would not look natural to us because it violates our sense of the arrow of time.</p>
<p>The apparent uniformity of CO2 in the container is due to the statistically significant quantity of dry ice we placed there. If we manage to put a small quantity, say five molecules of CO2, we can fully expect to see the congregation of the molecules in one location once in a while. Thus, the arrow of time manifests itself as a statistical or thermodynamic property. Although the directionality of time seems to emerge from reversible physical laws, its absence in the fundamental laws does look less than satisfactory philosophically.</p>
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		<title>Half a Bucket of Water</title>
		<link>http://www.thulasidas.com/2009-10/half-a-bucket-of-water.htm</link>
		<comments>http://www.thulasidas.com/2009-10/half-a-bucket-of-water.htm#comments</comments>
		<pubDate>Fri, 02 Oct 2009 00:17:38 +0000</pubDate>
		<dc:creator>Manoj</dc:creator>
				<category><![CDATA[philosophy]]></category>
		<category><![CDATA[physics]]></category>
		<category><![CDATA[Science]]></category>
		<category><![CDATA[quantitative finance]]></category>
		<category><![CDATA[relativity]]></category>
		<category><![CDATA[space and time]]></category>

		<guid isPermaLink="false">http://www.thulasidas.com/?p=1479</guid>
		<description><![CDATA[When philosophers look at anything, it becomes a bit technical. Their technical analysis may sound boring and irrelevant. Here is an attempt to tilt things in their favor. <a href="http://www.thulasidas.com/2009-10/half-a-bucket-of-water.htm">Continue reading <span class="meta-nav">&#8594;</span></a>]]></description>
			<content:encoded><![CDATA[<p>We all see and feel space, but what is it really? Space is one of those fundamental things that a philosopher may consider an &#8220;intuition.&#8221; When philosophers look at anything, they get a bit technical. Is space relational, as in, defined in terms of relations between objects? A relational entity is like your family &#8212; you have your parents, siblings, spouse, kids etc. forming what you consider your family. But your family itself is not a physical entity, but only a collection of relationships. Is space also something like that? Or is it more like a physical container where objects reside and do their thing?</p>
<p>You may consider the distinction between the two just another one of those philosophical hairsplittings, but it really is not. What space is, and even what kind of entity space is, has enormous implications in physics. For instance, if it is relational in nature, then in the absence of matter, there is no space. Much like in the absence of any family members, you have no family. On the other hand, if it is a container-like entity, the space exists even if you take away all matter, waiting for some matter to appear.</p>
<p>So what, you ask? Well, let&#8217;s take half a bucket of water and spin it around. Once the water within catches on, its surface will form a parabolic shape &#8212; you know, centrifugal force, gravity, surface tension and all that. Now, stop the bucket, and spin the whole universe around it instead. I know, it is more difficult. But imagine you are doing it. Will the water surface be parabolic? I think it will be, because there is not much difference between the bucket turning or the whole universe spinning around it.</p>
<p>Now, let&#8217;s imagine that we empty the universe. There is nothing but this half-full bucket. Now it spins around. What happens to the water surface? If space is relational, in the absence of the universe, there is no space outside the bucket and there is no way to know that it is spinning. Water surface should be flat. (In fact, it should be spherical, but ignore that for a second.) And if space is container-like, the spinning bucket should result in a parabolic surface.</p>
<p>Of course, we have no way of knowing which way it is going to be because we have no way of emptying the universe and spinning a bucket. But that doesn&#8217;t prevent us from guessing the nature of space and building theories based on it. Newton&#8217;s space is container-like, while at their heart, Einstein&#8217;s theories have a relational notion of space.</p>
<p>So, you see, philosophy does matter.</p>
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		<title>Modeling the Models</title>
		<link>http://www.thulasidas.com/2009-08/modeling-the-models.htm</link>
		<comments>http://www.thulasidas.com/2009-08/modeling-the-models.htm#comments</comments>
		<pubDate>Fri, 31 Jul 2009 23:00:03 +0000</pubDate>
		<dc:creator>Manoj</dc:creator>
				<category><![CDATA[Columns]]></category>
		<category><![CDATA[corporate life]]></category>
		<category><![CDATA[physics]]></category>
		<category><![CDATA[Quantitative Finance]]></category>
		<category><![CDATA[The Wilmott Magazine]]></category>
		<category><![CDATA[quantitative finance]]></category>
		<category><![CDATA[wilmott]]></category>

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		<description><![CDATA[Mathematical finance is built on a couple of assumptions. The most fundamental of them is the one on market efficiency.  Is it wise to trust this assumption? Are there limits to it? Are we operating at the right scale to ignore the shakiness of the market efficiency assumption? <a href="http://www.thulasidas.com/2009-08/modeling-the-models.htm">Continue reading <span class="meta-nav">&#8594;</span></a>]]></description>
			<content:encoded><![CDATA[<p>Mathematical finance is built on a couple of assumptions. The most fundamental of them is the one on market efficiency. It states that the market prices every asset fairly, and the prices contain all the information available in the market. In other words, you cannot glean any more information by doing any research or technical analysis, or indeed any modeling. If this assumption doesn&#8217;t pan out, then the quant edifice we build on top of it will crumble. Some may even say that it did crumble in 2008.</p>
<p>We know that this assumption is not quite right. If it was, there wouldn&#8217;t be any transient arbitrage opportunities. But even at a more fundamental level, the assumption has shaky justification. The reason that the market is efficient is that the practitioners take advantage of every little arbitrage opportunity. In other words, the markets are efficient because they are not so efficient at some transient level.</p>
<p>Mark Joshi, in his well-respected book, &#8220;The Concepts and Practice of Mathematical Finance,&#8221; points out that Warren Buffet made a bundle of money by refusing to accept the assumption of market efficiency. In fact, the weak form of market efficiency comes about because there are thousands of Buffet wannabes who keep their eyes glued to the ticker tapes, waiting for that elusive mispricing to show up.</p>
<p>Given that the quant careers, and literally trillions of dollars, are built on the strength of this assumption, we have to ask this fundamental question. Is it wise to trust this assumption? Are there limits to it?</p>
<p>Let&#8217;s take an analogy from physics. I have this glass of water on my desk now. Still water, in the absence of any turbulence, has a flat surface. We all know why &#8211; gravity and surface tension and all that. But we also know that the molecules in water are in random motion, in accordance with the same Brownian process that we readily adopted in our quant world. One possible random configuration is that half the molecules move, say, to the left, and the other half to the right (so that the net momentum is zero).</p>
<p>If that happens, the glass on my desk will break and it will make a terrible mess. But we haven&#8217;t heard of such spontaneous messes (from someone other than our kids, that is.)</p>
<p>The question then is, can we accept the assumption on the predictability of the surface of water although we know that the underlying motion is irregular and random? (I am trying to make a rather contrived analogy to the assumption on market efficiency despite the transient irregularities.) The answer is a definite yes. Of course, we take the flatness of liquid surfaces for granted in everything from the useless lift-pumps and siphons of our grade school physics books all the way to dams and hydro-electric projects.</p>
<p>So what am I quibbling about? Why do I harp on the possibility of uncertain foundations? I have two reasons. One is the question of scale. In our example of surface flatness vs. random motion, we looked at a very large collection, where, through the central limit theorem and statistical mechanics, we expect nothing but regular behavior. If I was studying, for instance, how an individual virus propagates through the blood stream, I shouldn&#8217;t make any assumptions on the regularity in the behavior of water molecules. This matter of scale applies to quantitative finance as well. Are we operating at the right scale to ignore the shakiness of the market efficiency assumption?</p>
<p>The second reason for mistrusting the pricing models is a far more insidious one. Let me see if I can present it rather dramatically using my example of the tumbler of water. Suppose we make a model for the flatness of the water surface, and the tiny ripples on it as perturbations or something. Then we proceed to use this model to extract tiny amounts of energy from the ripples.</p>
<p>The fact that we are using the model impacts the flatness or the nature of the ripples, affecting the underlying assumptions of the model. Now, imagine that a large number of people are using the same model to extract as much energy as they can from this glass of water. My hunch is that it will create large scale oscillations, perhaps generating configurations that do indeed break the glass and make a mess. Discounting the fact that this hunch has its root more in the financial mess that spontaneously materialized rather than any solid physics argument, we can still see that large fluctuations do indeed seem to increase the energy that can be extracted. Similarly, large fluctuations (and the black swans) may indeed be a side effect of modeling.</p>
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		<title>Change the Facts</title>
		<link>http://www.thulasidas.com/2009-02/change-the-facts.htm</link>
		<comments>http://www.thulasidas.com/2009-02/change-the-facts.htm#comments</comments>
		<pubDate>Mon, 23 Feb 2009 11:43:38 +0000</pubDate>
		<dc:creator>Manoj</dc:creator>
				<category><![CDATA[Creative]]></category>
		<category><![CDATA[philosophy]]></category>
		<category><![CDATA[physics]]></category>
		<category><![CDATA[Quotes]]></category>
		<category><![CDATA[Science]]></category>
		<category><![CDATA[Albert Einstein]]></category>

		<guid isPermaLink="false">http://www.thulasidas.com/?p=1077</guid>
		<description><![CDATA[Of truth and beauty -- in physics and philosophy <a href="http://www.thulasidas.com/2009-02/change-the-facts.htm">Continue reading <span class="meta-nav">&#8594;</span></a>]]></description>
			<content:encoded><![CDATA[<p>There is beauty in truth, and truth in beauty. Where does this link between truth and beauty come from? Of course, beauty is subjective, and truth is objective &#8212; or so we are told. It may be that we have evolved in accordance with the beautiful Darwinian principles to see perfection in absolute truth.</p>
<p>The beauty and perfection I&#8217;m thinking about are of a different kind &#8212; those of ideas and concepts. At times, you may get an idea so perfect and beautiful that you know it has to be true. This conviction of truth arising from beauty may be what made Einstein declare:</p>
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<p>But this conviction about the veracity of a theory based on its perfection is hardly enough. Einstein&#8217;s genius really is in his philosophical tenacity, his willingness to push the idea beyond what is considered logical.</p>
<p>Let&#8217;s take an example. Let&#8217;s say you are in a cruising airplane. If you close the windows and somehow block out the engine noise, it will be impossible for you to tell whether you are moving or not. This inability, when translated to physics jargon, becomes a principle stating, &#8220;Physical laws are independent of the state of motion of the experimental system.&#8221;</p>
<p>The physical laws Einstein chose to look at were Maxwell&#8217;s equations of electromagnetism, which had the speed of light appearing in them. For them to be independent of (or covariant with, to be more precise) motion, Einstein postulated that the speed of light had to be a constant regardless of whether you were going toward it or away from it.</p>
<p>Now, I don&#8217;t know if you find that postulate particularly beautiful. But Einstein did, and decided to push it through all its illogical consequences. For it to be true, space has to contract and time had to dilate, and nothing could go faster than light. Einstein said, well, so be it. That is the philosophical conviction and tenacity that I wanted to talk about &#8212; the kind that gave us Special Relativity about a one hundred years ago.</p>
<p>Want to get to General Relativity from here? Simple, just find another beautiful truth. Here is one&#8230; If you have gone to Magic Mountain, you would know that you are weightless during a free fall (best tried on an empty stomach). Free fall is acceleration at 9.8 m/s/s (or 32 ft/s/s), and it nullifies gravity. So gravity is the same as acceleration &#8212; voila, another beautiful principle.</p>
<p><img src="/img/xt.png" alt="World line of airplanes" title="World lines of airplanes" class="alignleft" />In order to make use of this principle, Einstein perhaps thought of it in pictures. What does acceleration mean? It is how fast the speed of something is changing. And what is speed? Think of something moving in a straight line &#8212; our cruising airplane, for instance, and call the line of flight the X-axis. We can visualize its speed by thinking of a time T-axis at right angles with the X-axis so that at time = 0, the airplane is at x = 0. At time t, it is at a point x = v.t, if it is moving with a speed v. So a line in the X-T plane (called the world line) represents the motion of the airplane. A faster airplane would have a shallower world line. An accelerating airplane, therefore, will have a curved world line, running from the slow world line to the fast one.</p>
<p>So acceleration is curvature in space-time. And so is gravity, being nothing but acceleration. (I can see my physicist friends cringe a bit, but it is essentially true &#8212; just that you straighten the world-line calling it a geodesic and attribute <a href="http://www.thulasidas.com/2006-11/of-rotation-lt-and-acceleration.htm">the curvature to space-time</a> instead.)</p>
<p>The exact nature of the curvature and how to compute it, though beautiful in their own right, are mere details, as Einstein himself would have put it. After all, he wanted to know God&#8217;s thoughts, not the details.</p>
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		<title>Global Warming and the Flu</title>
		<link>http://www.thulasidas.com/2009-02/global-warming-and-the-flu.htm</link>
		<comments>http://www.thulasidas.com/2009-02/global-warming-and-the-flu.htm#comments</comments>
		<pubDate>Wed, 18 Feb 2009 22:38:09 +0000</pubDate>
		<dc:creator>Manoj</dc:creator>
				<category><![CDATA[Columns]]></category>
		<category><![CDATA[Environment]]></category>
		<category><![CDATA[philosophy]]></category>
		<category><![CDATA[Science]]></category>
		<category><![CDATA[The Today Paper]]></category>
		<category><![CDATA[physics]]></category>

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		<description><![CDATA[An unreal look at global warming. Are we a virus on the earth? And is the global warming a bout of fever? Published in the Singaporean newspaper, Today, on 1 Dec 2008.  <a href="http://www.thulasidas.com/2009-02/global-warming-and-the-flu.htm">Continue reading <span class="meta-nav">&#8594;</span></a>]]></description>
			<content:encoded><![CDATA[<p>On one poignantly beautiful autumn day in Syracuse, a group of us physics graduate students were gathered around a frugal kitchen table. We had our brilliant professor, Lee Smolin, talking to us. We held our promising mentors in very high regard. And we had high hopes for Lee.</p>
<p>The topic of conversation on that day was a bit philosophical, and we were eagerly absorbing the words of wisdom emanating from Lee. He was describing to us how the Earth could be considered a living organism. Using insightful arguments and precisely modulated glib articulation (no doubt, forged by years of intellectual duels in world&#8217;s best universities), Lee made a compelling case that the Earth, in fact, satisfied all the conditions of being an organism.</p>
<p>Lee Smolin, by the way, lived up to our great expectations in later years, publishing highly acclaimed books and generally leaving a glorious imprint in the world of modern physics. He now talks to global audiences through prestigious programmes such as the BBC Hardtalk, much to our pride and joy.</p>
<p>The point in Lee&#8217;s view was not so much whether or the Earth was literally alive, but that thinking of it as an organism was a viable intellectual model to represent the Earth. Such intellectual acrobatics was not uncommon among us physics students.</p>
<p>In the last few years, Lee has actually taken this mode of thinking much farther in one of his books, picturing the universe in the light of evolution. Again, the argument is not to be taken literally, imagining a bunch of parallel universes vying for survival. The idea is to let the mode of thinking carry us forward and guide our thoughts, and see what conclusions we can draw from the thought exercise.</p>
<p>A similar mode of thinking was introduced in the movie Matrix. In fact, several profound models were introduced in that movie, which probably fuelled its wild box-office success. One misanthropic model that the computer agent Smith proposes is that human beings are a virus on our planet.</p>
<p>It is okay for the bad guy in a movie to suggest it, but an entirely different matter for newspaper columnist to do so. But bear with me as I combine Lee&#8217;s notion of the Earth being an organism and Agent Smith&#8217;s suggestion of us being a virus on it. Let&#8217;s see where it takes us.</p>
<p>The first thing a virus does when it invades an organism is to flourish using the genetic material of the host body. The virus does it with little regard for the well-being of the host. On our part, we humans plunder the raw material from our host planet with such abandon that the similarity is hard to miss.</p>
<p>But the similarity doesn&#8217;t end there. What are the typical symptoms of a viral infection on the host? One symptom is a bout of fever. Similarly, due to our activities on our host planet, we are going through a bout of global warming. Eerily similar, in my view.</p>
<p>The viral symptoms could extend to sores and blisters as well. Comparing the cities and other eye sores that we proudly create to pristine forests and natural landscapes, it is not hard to imagine that we are indeed inflicting fetid atrocities to our host Earth. Can&#8217;t we see the city sewers and the polluted air as the stinking, oozing ulcers on its body?</p>
<p>Going one step further, could we also imagine that natural calamities such as Katrina and the Asian tsunami are the planet&#8217;s natural immune systems kicking into high gear?</p>
<p>I know that it is supremely cynical to push this comparison to these extreme limits. Looking at the innocent faces of your loved ones, you may feel rightfully angry at this comparison. How dare I call them an evil virus? Then again, if a virus could think, would it think of its activities on a host body as evil?</p>
<p>If that doesn&#8217;t assuage your sense of indignation, remember that this virus analogy is a mode of thinking rather than a literal indictment. Such a mode of thinking is only useful if it can yield some conclusions. What are the conclusions from this human-viral comparison?</p>
<p>The end result of a viral infection is always gloomy. Either the host succumbs or the virus gets beaten by the host&#8217;s immune systems. If we are the virus, both these eventualities are unpalatable. We don&#8217;t want to kill the Earth. And we certainly don&#8217;t want to be exterminated by the Earth. But those are the only possible outcomes of our viral-like activity here. It is unlikely that we will get exterminated; we are far too sophisticated for that. In all likelihood, we will make our planet uninhabitable. We may, by then, have our technological means of migrating to other planetary systems. In other words, if we are lucky, we may be contagious! This is the inescapable conclusion of this intellectual exercise.</p>
<p>There is a less likely scenario &#8212; a symbiotic viral existence in a host body. It is the kind of benign life style that Al Gore and others recommend for us. But, taking stock of our activities on the planet, my doomsday view is that it is too late for a peaceful symbiosis. What do you think?</p>
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		<title>The Unreal Universe &#8211; Reviewed</title>
		<link>http://www.thulasidas.com/2008-12/the-unreal-universe-reviewed.htm</link>
		<comments>http://www.thulasidas.com/2008-12/the-unreal-universe-reviewed.htm#comments</comments>
		<pubDate>Sun, 07 Dec 2008 14:16:30 +0000</pubDate>
		<dc:creator>Manoj</dc:creator>
				<category><![CDATA[Books]]></category>
		<category><![CDATA[Creative]]></category>
		<category><![CDATA[book reviews]]></category>
		<category><![CDATA[metaphysics]]></category>
		<category><![CDATA[philosophy]]></category>
		<category><![CDATA[physics]]></category>
		<category><![CDATA[relativity]]></category>

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		<description><![CDATA[This post is a collection of reviews of my first book The Unreal Universe. As I'm beginning to work on my second book (Principles of Quantitative Development, commissioned by Wiley-Finance), I felt that these thoughts on my first book might be of interest to some of you. <a href="http://www.thulasidas.com/2008-12/the-unreal-universe-reviewed.htm">Continue reading <span class="meta-nav">&#8594;</span></a>]]></description>
			<content:encoded><![CDATA[<h4>The Straits Times</h4>
<p><img class="alignleft" src="/img/pback-cover.gif" alt="pback-cover (17K)" />The national newspaper of Singapore, the Straits Times, lauds the readable and conversation style used in <em>The Unreal Universe</em> and recommends it to anybody who wants to learn about life, the universe and everything.<br />
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<h4><a title="Wendy is the Senior Executive Editor for Religion, Philosophy and Animal Studies at Columbia University Press." href="javascript:popUpFat('http://cup.columbia.edu/static/Wendy-Lochner')">Wendy Lochner</a></h4>
<p>Calling <em>The Unreal Universe</em> a good read, Wendy says, &#8220;It&#8217;s well written, very clear to follow for the nonspecialist.&#8221;</p>
<h4><a title="Bobbie is the author of Write In Style, a   triple-award-winning textbook for writers of fiction and nonfiction. She is the Owner of Zebra Communications, Atlanta, GA (since 1992). She is editor, ghostwriter, book doctor, copywriter, consultant, seminar and workshop leader." href="javascript:popUpFat('http://www.zebraeditor.com/mentor.shtml')">Bobbie Christmas</a></h4>
<p>Describing <em>The Unreal Universe</em> as &#8220;such an insightful and intelligent book,&#8221; Bobbie says, &#8220;A book for thinking laymen, this readable, thought-provoking work offers a new perspective on our definition of reality.&#8221;</p>
<h4>M. S. Chandramouli</h4>
<p>M. S. Chandramouli graduated from the Indian Institute of Technology, Madras in 1966 and subsequently did his MBA from the Indian Institute of Management, Ahmedabad. After an executive career in India and Europe covering some 28 years he founded Surya International in Belgium through which he now offers business development and industrial marketing services.</p>
<p>Here is what he says about <em>The Unreal Universe</em>:</p>
<blockquote><p>&#8220;The book has a very pleasing layout, with the right size of font and line spacing and correct content density. Great effort for a self-published book!&#8221;</p>
<p>&#8220;The impact of the book is kaleidoscopic. The patterns in one reader&#8217;s mind (mine, that is) shifted and re-arranged themselves with a &#8216;rustling noise&#8217; more than once.&#8221;"The author&#8217;s writing style is remarkably equidistant from the turgid prose of Indians writing on philosophy or religion and the we-know-it-all style of Western authors on the philosophy of science.&#8221;</p>
<p>&#8220;There is a sort of cosmic, background &#8216;Eureka!&#8217; that seems to suffuse the entire book. Its central thesis about the difference between perceived reality and absolute reality is an idea waiting to bloom in a million minds.&#8221;</p>
<p>&#8220;The test on the &#8216;Emotionality of Faith,&#8217; Page 171, was remarkably prescient; it worked for me!&#8221;</p>
<p>&#8220;I am not sure that the first part, which is essentially descriptive and philosophical, sits comfortably with the second part with its tightly-argued physics; if and when the author is on his way to winning the argument, he may want to look at three different categories of readers &#8211; the lay but intelligent ones who need a degree of &#8216;translation,&#8217; the non-physicist specialist, and the physicist philosophers. Market segmentation is the key to success.&#8221;</p>
<p>&#8220;I think this book needs to be read widely. I am making a small attempt at plugging it by copying this to my close friends.&#8221;</p></blockquote>
<h4>Steven Bryant</h4>
<p>Steven is a Vice President of Consulting Services for <a href="javascript:popUpFat('http://www.primitivelogic.com')">Primitive Logic</a>, a premier Regional Systems Integrator located in San Francisco, California. He is the author of <a href="javascript:popUpFat('http://www.relativitychallenge.com/index.htm')">The Relativity Challenge</a>.</p>
<blockquote><p>&#8220;Manoj views science as just one element in the picture of life. Science does not define life. But life colors how we understand science. He challenges all readers to rethink their believe systems, to question what they thought was real, to ask &#8220;why&#8221;? He asks us to take off our &#8220;rose colored glasses&#8221; and unlock new ways of experiencing and understanding life. This thought provoking work should be required reading to anyone embarking on a new scientific journey.&#8221;</p>
<p>&#8220;Manoj&#8217;s treatment of time is very thought provoking. While each of our other senses &#8211; sight, sound, smell, taste and touch &#8211; are multi-dimensional, time appears to be single dimensional. Understanding the interplay of time with our other senses is a very interesting puzzle. It also opens to door to the existence possibilities of other phenomena beyond our know sensory range.&#8221;</p>
<p>&#8220;Manoj&#8217;s conveys a deep understanding of the interaction of our physics, human belief systems, perceptions, experiences, and even our languages, on how we approach scientific discovery. His work will challenge you to rethink what you think you know is true.&#8221;</p>
<p>&#8220;Manoj offers a unique perspective on science, perception, and reality. The realization that science does not lead to perception, but perception leads to science, is key to understanding that all scientific &#8220;facts&#8221; are open for re-exploration. This book is extremely thought provoking and challenges each reader the question their own beliefs.&#8221;</p>
<p>&#8220;Manoj approaches physics from a holistic perspective. Physics does not occur in isolation, but is defined in terms of our experiences &#8211; both scientific and spiritual. As you explore his book you&#8217;ll challenge your own beliefs and expand your horizons.&#8221;</p></blockquote>
<h4>Blogs and Found Online</h4>
<p>From the Blog <a href="javascript:popUpFat('http://a-cro.net/throughthelookingglass/?p=33')">Through The Looking Glass</a></p>
<blockquote><p>&#8220;This book is considerably different from other books in its approach to philosophy and physics. It contains numerous practical examples on the profound implications of our philosophical viewpoint on physics, specifically astrophysics and particle physics. Each demonstration comes with a mathematical appendix, which includes a more rigorous derivation and further explanation. The book even reins in diverse branches of philosophy (e.g. thinking from both the East and the West, and both the classical period and modern contemporary philosophy). And it is gratifying to know that all the mathematics and physics used in the book are very understandable, and thankfully not graduate level. That helps to make it much easier to appreciate the book.&#8221;</p></blockquote>
<p>From the <a href="javascript:popUpFat('http://hubpages.com/hub/Singapore_Books_Review_1')">Hub Pages</a></p>
<p>Calling itself &#8220;An Honest Review of <em>The Unreal Universe</em>,&#8221; this review looks like the one used in <a href="javascript:popUpFat('st.pdf')">the Straits Times</a>.</p>
<p>I got a few reviews from my readers through email and online forums. I have compiled them as anonymous reviews in the next page of this post.</p>
<p>Click on the link below to visit the second page.</p>
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		<title>The Big Bang Theory &#8211; Part II</title>
		<link>http://www.thulasidas.com/2008-11/the-big-bang-theory-part-ii.htm</link>
		<comments>http://www.thulasidas.com/2008-11/the-big-bang-theory-part-ii.htm#comments</comments>
		<pubDate>Wed, 19 Nov 2008 23:35:22 +0000</pubDate>
		<dc:creator>Manoj</dc:creator>
				<category><![CDATA[Debates]]></category>
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		<description><![CDATA[This post is a continuation of my earlier musings on the Big Bang theory. This one looks at the foundational assumptions of quantum gravity. In management speak, it is a high level overview, which sounds like I understand it. In a physicist's lingo, it is merely a layman description or a hand-waving argument. In other words, the management types out there may like it better than the smart ones. You be the judge! <a href="http://www.thulasidas.com/2008-11/the-big-bang-theory-part-ii.htm">Continue reading <span class="meta-nav">&#8594;</span></a>]]></description>
			<content:encoded><![CDATA[<p>After reading a <a href="http://arxiv.org/abs/0810.0514" target="_blank">paper by Ashtekar</a> on quantum gravity and thinking about it, I realized what my trouble with the Big Bang theory was. It is more on the fundamental assumptions than the details. I thought I would summarize my thoughts here, more for my own benefit than anybody else&#8217;s.</p>
<p>Classical theories (including SR and QM) treat space as continuous nothingness; hence the term space-time continuum. In this view, objects exist in continuous space and interact with each other in continuous time.</p>
<p>Although this notion of space time continuum is intuitively appealing, it is, at best, incomplete. Consider, for instance, a spinning body in empty space. It is expected to experience centrifugal force. Now imagine that the body is stationary and the whole space is rotating around it. Will it experience any centrifugal force?</p>
<p>It is hard to see why there would be any centrifugal force if space is empty nothingness.</p>
<p>GR introduced a paradigm shift by encoding gravity into space-time thereby making it dynamic in nature, rather than empty nothingness. Thus, mass gets enmeshed in space (and time), space becomes synonymous with the universe, and the spinning body question becomes easy to answer. Yes, it will experience centrifugal force if it is the universe that is rotating around it because it is equivalent to the body spinning. And, no, it won&#8217;t, if it is in just empty space. But &#8220;empty space&#8221; doesn&#8217;t exist. In the absence of mass, there is no space-time geometry.</p>
<p>So, naturally, before the Big Bang (if there was one), there couldn&#8217;t be any space, nor indeed could there be any &#8220;before.&#8221; Note, however, that the Ashtekar paper doesn&#8217;t clearly state why there had to be a big bang. The closest it gets is that the necessity of BB arises from the encoding of gravity in space-time in GR. Despite this encoding of gravity and thereby rendering space-time dynamic, GR still treats space-time as a smooth continuum &#8212; a flaw, according to Ashtekar, that QG will rectify.</p>
<p>Now, if we accept that the universe started out with a big bang (and from a small region), we have to account for quantum effects. Space-time has to be quantized and the only right way to do it would be through quantum gravity. Through QG, we expect to avoid the Big Bang singularity of GR, the same way QM solved the unbounded ground state energy problem in the hydrogen atom.</p>
<p>What I described above is what I understand to be the physical arguments behind modern cosmology. The rest is a mathematical edifice built on top of this physical (or indeed philosophical) foundation. If you have no strong views on the philosophical foundation (or if your views are consistent with it), you can accept BB with no difficulty. Unfortunately, I do have differing views.</p>
<p>My views revolve around the following questions. </p>
<ul>
<li><a href="/2008-11/what-is-space.htm" target="_blank">What is space?</a></li>
<li><a href="/2008-11/why-the-speed-of-light.htm" target="_blank">Why is the speed of light important in it?</a></li>
<li>Where does the <a href="/2008-08/uncertainly-principle.htm" target="_blank">Heisenberg Uncertainty Principle</a> come from?</li>
</ul>
<p>These posts may sound like useless philosophical musings, but I do have some concrete (and in my opinion, important) results, listed below. </p>
<ul>
<li><a href="/2008-11/are-radio-sources-and-gamma-ray-bursts-luminal-booms.htm" target="_blank">Are GRBs and Radio Sources Luminal Booms?</a> (An article published in IJMP-D, which became one of the &#8220;Top Accessed Articles&#8221; of the journal.  <img src='http://www.thulasidas.com/wp-includes/images/smilies/icon_smile.gif' alt=':-)' class='wp-smiley' /> )</li>
<li><a href="/2008-11/light-travel-time-effects-and-cosmological-features.htm" target="_blank">Light Travel Time Effects and Cosmological Features</a> (Trying to get this one published.)</li>
</ul>
<p>There is much more work to be done on this front. But for the next couple of years, with my new book contract and pressures from my quant career, I will not have enough time to study GR and cosmology with the seriousness they deserve. I hope to get back to them once the current phase of spreading myself too thin passes. </p>
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		<title>Chaos and Uncertainty</title>
		<link>http://www.thulasidas.com/2008-11/chaos-and-uncertainty.htm</link>
		<comments>http://www.thulasidas.com/2008-11/chaos-and-uncertainty.htm#comments</comments>
		<pubDate>Thu, 13 Nov 2008 01:24:33 +0000</pubDate>
		<dc:creator>Manoj</dc:creator>
				<category><![CDATA[Columns]]></category>
		<category><![CDATA[physics]]></category>
		<category><![CDATA[Quantitative Finance]]></category>
		<category><![CDATA[The Wilmott Magazine]]></category>
		<category><![CDATA[chaos]]></category>
		<category><![CDATA[financial meltdown]]></category>
		<category><![CDATA[management]]></category>
		<category><![CDATA[non-linear dynamics]]></category>
		<category><![CDATA[quantitative finance]]></category>
		<category><![CDATA[uncertainty principle]]></category>

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		<description><![CDATA[This article appeared in the Wilmott Magazine in Jan 2009, and talks not quite about the chaos and uncertainty of the last few months in finance industry can be summarized in two words. It is more about the physics concepts bearing the same names, and how they can be applied to the turmoil in the financial and economic world. <a href="http://www.thulasidas.com/2008-11/chaos-and-uncertainty.htm">Continue reading <span class="meta-nav">&#8594;</span></a>]]></description>
			<content:encoded><![CDATA[<p>The last couple of months in finance industry can be summarized in two words &#8212; chaos and uncertainty. The aptness of this laconic description is all too evident. The sub-prime crisis where everybody lost, the dizzying commodity price movements, the pink slip syndrome, the spectacular bank busts and the gargantuan bail-outs all vouch for it.</p>
<p>The financial meltdown is such a rich topic with reasons and ramifications so overarching that all self-respecting columnists will be remiss to let it slide. After all, a columnist who keeps his opinions to himself is a columnist only in his imagination. I too will share my views on causes and effects of this turmoil that is sure to affect our lives more directly than anybody else&#8217;s, but perhaps in a future column.</p>
<p>The chaos and uncertainty I want to talk about are of different kind &#8212; the physics kind. The terms chaos and uncertainty have a different and specific meanings in physics. How those meanings apply to the world of finance is what this column is about.</p>
<h4>Symmetries and Patterns</h4>
<p>Physicists are a strange bunch. They seek and find symmetries and patterns where none exists. I remember once when our brilliant professor, Lee Smolin, described to us how the Earth could be considered a living organism. Using insightful arguments and precisely modulated articulation, Lee made a compelling case that the Earth, in fact, satisfied all the conditions of being an organism. The point in Lee&#8217;s view was not so much whether or the Earth was literally alive, but that thinking of it as an organism was a viable intellectual pattern. Once we represent the Earth in that model, we can use the patterns pertaining to organism to draw further predictions or conclusions.</p>
<p>Expanding on this pattern, I recently published a column presenting the global warming as a bout of fever caused by a virus (us humans) on this host organism. Don&#8217;t we plunder the raw material of our planet with the same abandon with which a virus usurps the genetic material of its host? In addition to fever, typical viral symptoms include sores and blisters as well. Looking at the cities and other eye sores that have replaced pristine forests and other natural landscapes, it is not hard to imagine that we are indeed inflicting fetid atrocities to our host Earth. Can&#8217;t we think of our city sewers and the polluted air as the stinking, oozing ulcers on its body?</p>
<p>While these analogies may sound farfetched, we have imported equally distant ideas from physics to mathematical finance. Why would stock prices behave anything like a random walk, unless we want to take Bush&#8217;s words (that &#8220;Wall Street got drunk&#8221;) literally? But seriously, Brownian motion has been a wildly successful model that we borrowed from physics. Again, once we accept that the pattern is similar between molecules getting bumped around and the equity price movements, the formidable mathematical machinery and physical intuitions available in one phenomenon can be brought to bear on the other.</p>
<p>Looking at the chaotic financial landscape now, I wonder if physics has other insights to offer so that we can duck and dodge as needed in the future. Of the many principles from physics, chaos seems such a natural concept to apply to the current situation. Are there lessons to be learned from chaos and nonlinear dynamics that we can make use of? May be it is Heisenberg&#8217;s uncertainty principle that holds new insights.</p>
<p>Perhaps I chose these concepts as a linguistic or emotional response to the baffling problems confronting us now, but let&#8217;s look at them any way. It is not like the powers that be have anything better to offer, is it?</p>
<h4>Chaos Everywhere</h4>
<p>In physics, chaos is generally described as our inability to predict the outcome of experiments with arbitrarily close initial conditions. For instance, try balancing your pencil on its tip. Clearly, you won&#8217;t be able to, and the pencil will land on your desktop. Now, note this line along which it falls, and repeat the experiment. Regardless of how closely you match the initial conditions (of how you hold and balance the pencil), the outcome (the line along which it falls) is pretty much random. Although this randomness may look natural to us &#8212; after all, we have been trying to balance pencils on their tips ever since we were four, if my son’s endeavours are anything to go by &#8212; it is indeed strange that we cannot bring the initial conditions close enough to be confident of the outcome.</p>
<p>Even stranger is the fact that similar randomness shows up in systems that are not quite as physical as pencils or experiments. Take, for instance, the socio-economic phenomenon of globalization, which I can describe as follows, admittedly with an incredible amount of over-simplification. Long time ago, we used to barter agricultural and dairy products with our neighbours &#8212; say, a few eggs for a litre (or was it pint?) of milk. Our self-interest ensured a certain level of honesty. We didn&#8217;t want to get beaten up for adding white paint to milk, for instance. These days, thanks to globalization, people don&#8217;t see their customers. A company buys milk from a farmer, adds god knows what, makes powder and other assorted chemicals in automated factories and ships them to New Zealand and Peru. The absence of a human face in the supply chain and in the flow of money results in increasingly unscrupulous behaviour.</p>
<p>Increasing chaos can be seen in the form of violently fluctuating concentrations of wealth and fortunes, increasing amplitudes and frequency of boom and bust cycles, exponential explosion in technological innovation and adaptation cycles, and the accelerated pace of paradigm shifts across all aspects of our lives.</p>
<p>It is one thing to say that things are getting chaotic, quite another matter to exploit that insight and do anything useful with it. I won&#8217;t pretend that I can predict the future even if (rather, especially if) I could. However, let me show you a possible approach using chaos.</p>
<p>One of the classic examples of chaos is the transition from a regular, laminar flow of a fluid to a chaotic, turbulent flow. For instance, when you open a faucet slowly, if you do it carefully, you can have a pretty nice continuous column of water, thicker near the top and stretched thinner near the bottom. The stretching force is gravity, and the cohesive forces are surface tension and inter-molecular forces. As you open the faucet still further, ripples begin to appear on the surface of the column which, at higher rates of flow, rip apart the column into complete chaos.</p>
<p>In a laminar flow, macroscopic forces tend to smooth out microscopic irregularities. Like gravity and surface tension in our faucet example, we have analogues of macroscopic forces in finance. The stretching force is probably greed, and the cohesive ones are efficient markets.</p>
<p>There is a rich mathematical framework available to describe chaos. Using this framework, I suspect one can predict the incidence and intensity of financial turmoils, though not their nature and causes. However, I am not sure such a prediction is useful. Imagine if I wrote two years ago that in 2008, there would be a financial crisis resulting in about one trillion dollar of losses. Even if people believed me, would it have helped?</p>
<p>Usefulness is one thing, but physicists and mathematicians derive pleasure also from useless titbits of knowledge. What is interesting about the faucet-flow example is this: if you follow the progress two water molecules starting off their careers pretty close to each other, in the laminar case, you will find that they end up pretty much next to each other. But once the flow turns turbulent, there is not telling where the molecules will end up. Similarly, in finance, suppose two banks start off roughly from the same position &#8212; say Bear Stearns and Lehman. Under normal, laminar conditions, their stock prices would track similar patterns. But during a financial turbulence, they end up in totally different recycle bins of history, as we have seen.</p>
<p>If whole financial institutions are tossed around into uncertain paths during chaotic times, imagine where two roughly similar employees might end up. In other words, don&#8217;t feel bad if you get a pink slip. There are forces well beyond your control at play here.</p>
<h4>Uncertainty Principle in Quantitative Finance</h4>
<p>The Heisenberg uncertainty principle is perhaps the second most popular theme from physics that has captured the public imagination. (The first one, of course, is Einstein&#8217;s E = mc2.) It says something seemingly straightforward &#8212; you can measure two complementary properties of a system only to a certain precision. For instance, if you try to figure out where an electron is (measure its position, that is) more and more precisely, its speed becomes progressively more uncertain (or, the momentum measurement becomes imprecise).</p>
<p>Quantitative finance has a natural counterpart to the uncertainty principle &#8212; risks and rewards. When you try to minimize the risks, the rewards themselves go down. If you hedge out all risks, you get only risk-free returns. Since risk is the same as the uncertainty in rewards, the risk-reward relation is not quite the same as the uncertainty principle (which, as described in the box, deals with complementary variables), but it is close enough to draw some parallels.</p>
<p>To link the quantum uncertainty principle to quantitative finance, let&#8217;s look at its interpretation as observation altering results. Does modelling affect how much money we can make out of a product? This is a trick question. The answer might look obvious at first glance. Of course, if we can understand and model a product perfectly, we can price it right and expect to reap healthy rewards. So, sure, modelling affects the risk-reward equation.</p>
<p>But, a model is only as good as its assumptions. And the most basic assumption in any model is that the market is efficient and liquid. The validity of this assumption (or lack thereof) is precisely what precipitated the current financial crisis. If our modelling effort actually changes the underlying assumptions (usually in terms of liquidity or market efficiency), we have to pay close attention to the quant equivalent of the uncertainty principle.</p>
<p>Look at it this way &#8212; a pyramid scheme is a perfectly valid money making model, but based on one unfortunate assumption on the infinite number of idiots at the bottom of the pyramid. (Coming to think of it, the underlying assumption in the sub-prime crisis, though more sophisticated, may not have been that different.) Similar pyramid assumptions can be seen in social security schemes, as well. We know that pyramid assumptions are incorrect. But at what point do they become incorrect enough for us to change the model?</p>
<p>There is an even more insidious assumption in using models &#8212; that we are the only ones who use them. In order to make a killing in a market, we always have to know a bit more than the rest of them. Once everybody starts using the same model, I think the returns will plummet to risk-free levels. Why else do you think we keep inventing more and more complex exotics?</p>
<h4>Summing up&#8230;</h4>
<p>The current financial crisis has been blamed on many things. One favourite theory has been that it was brought about by the greed in Wall Street &#8212; the so-called privatization of profits and socialization of losses. Incentive schemes skewed in such a way as to encourage risk taking and limit risk management must take at least part of the blame. A more tempered view regards the turmoil as a result of a risk management failure or a regulatory failure.</p>
<p>This column presents my personal view that the turmoil is the inevitable consequence of the interplay between opposing forces in financial markets &#8212; risk and rewards, speculation and regulation, risk taking and risk management and so on. To the extent that the risk appetite of a financial institute is implemented through a conflict between such opposing forces, these crises cannot be avoided. Worse, the intensity and frequency of similar meltdowns are going to increase as the volume of transactions increases. This is the inescapable conclusion from non-linear dynamics. After all, such turbulence has always existed in the real economy in the form cyclical booms and busts. In free market economies, selfishness and the inherent conflicts between selfish interests provide the stretching and cohesive forces, setting the stage for chaotic turbulence.</p>
<p>Physics has always been a source of talent and ideas for quantitative finance, much like mathematics provides a rich toolkit to physics. In his book, Dreams of a Final Theory, Nobel Prize winning physicist Steven Weinberg marvels at the uncanny ability of mathematics to anticipate physics needs. Similarly, quants may marvel at the ability of physics to come up with phenomena and principles that can be directly applied to our field. To me, it looks like the repertoire of physics holds a few more gems that we can employ and exploit.</p>
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<h4>Box: Heisenberg&#8217;s Uncertainty Principle</h4>
<p>Where does this famous principle come from? It is considered a question beyond the realms of physics. Before we can ask the question, we have to examine what the principle really says. Here are a few possible interpretations:</p>
<ul>
<li>Position and momentum of a particle are intrinsically interconnected. As we measure the momentum more accurately, the particle kind of &#8220;spreads out,&#8221; as George Gamow&#8217;s character, Mr. Tompkins, puts it. In other words, it is just one of those things; the way the world works.</li>
<li> When we measure the position, we disturb the momentum. Our measurement probes are &#8220;too fat,&#8221; as it were. As we increase the position accuracy (by shining light of shorter wavelengths, for instance), we disturb the momentum more and more (because shorter wavelength light has higher energy/momentum).</li>
<li> Closely related to this interpretation is a view that the uncertainty principle is a perceptual limit.</li>
<li> We can also think of the uncertainly principle as a cognitive limit if we consider that a future theory might surpass such limits.</li>
</ul>
<p>The first view is currently popular and is related to the so-called Copenhagen interpretation of quantum mechanics. Let’s ignore it for it is not too open to discussions.</p>
<p>The second interpretation is generally understood as an experimental difficulty. But if the notion of the experimental setup is expanded to include the inevitable human observer, we arrive at the third view of perceptual limitation. In this view, it is actually possible to &#8220;derive&#8221; the uncertainty principle, based on how human perception works.</p>
<p>Let&#8217;s assume that we are using a beam of light of wavelength <img src="http://l.wordpress.com/latex.php?latex=%5Clambda&#038;bg=FFFFFF&#038;fg=000000&#038;s=0" title="\lambda" style="vertical-align:-20%;" class="tex" alt="\lambda" /> to observe the particle. The precision in the position we can hope to achieve is of the order of <img src="http://l.wordpress.com/latex.php?latex=%5Clambda&#038;bg=FFFFFF&#038;fg=000000&#038;s=0" title="\lambda" style="vertical-align:-20%;" class="tex" alt="\lambda" />. In other words, <img src="http://l.wordpress.com/latex.php?latex=%5CDelta%20x%20%5Capprox%20%5Clambda&#038;bg=FFFFFF&#038;fg=000000&#038;s=0" title="\Delta x \approx \lambda" style="vertical-align:-20%;" class="tex" alt="\Delta x \approx \lambda" />. In quantum mechanics, the momentum of each photon in the light beam is inversely proportional to the wavelength. At least one photon is reflected by the particle so that we can see it. So, by the classical conservation law, the momentum of the particle has to change by at least this amount(<img src="http://l.wordpress.com/latex.php?latex=%5Capprox%20constant%2F%5Clambda&#038;bg=FFFFFF&#038;fg=000000&#038;s=0" title="\approx constant/\lambda" style="vertical-align:-20%;" class="tex" alt="\approx constant/\lambda" />) from what it was before the measurement. Thus, through perceptual arguments, we get something similar to the Heisenberg uncertainty principle <center><img src="http://l.wordpress.com/latex.php?latex=%5CDelta%20x.%5CDelta%20p%20%5Capprox%20constant&#038;bg=FFFFFF&#038;fg=000000&#038;s=0" title="\Delta x.\Delta p \approx constant" style="vertical-align:-20%;" class="tex" alt="\Delta x.\Delta p \approx constant" /></center></p>
<p>We can make this argument more rigorous, and get an estimate of the value of the constant. The resolution of a microscope is given by the empirical formula <img src="http://l.wordpress.com/latex.php?latex=0.61%5Clambda%2FNA&#038;bg=FFFFFF&#038;fg=000000&#038;s=0" title="0.61\lambda/NA" style="vertical-align:-20%;" class="tex" alt="0.61\lambda/NA" />, where <img src="http://l.wordpress.com/latex.php?latex=NA&#038;bg=FFFFFF&#038;fg=000000&#038;s=0" title="NA" style="vertical-align:-20%;" class="tex" alt="NA" /> is the numerical aperture, which has a maximum value of one. Thus, the best spatial resolution is <img src="http://l.wordpress.com/latex.php?latex=0.61%5Clambda&#038;bg=FFFFFF&#038;fg=000000&#038;s=0" title="0.61\lambda" style="vertical-align:-20%;" class="tex" alt="0.61\lambda" />. Each photon in the light beam has a momentum <img src="http://l.wordpress.com/latex.php?latex=2%5Cpi%5Chbar%2F%5Clambda&#038;bg=FFFFFF&#038;fg=000000&#038;s=0" title="2\pi\hbar/\lambda" style="vertical-align:-20%;" class="tex" alt="2\pi\hbar/\lambda" />, which is the uncertainty in the particle momentum. So we get <img src="http://l.wordpress.com/latex.php?latex=%5CDelta%20x.%5CDelta%20p%20%5Capprox%204%5Chbar&#038;bg=FFFFFF&#038;fg=000000&#038;s=0" title="\Delta x.\Delta p \approx 4\hbar" style="vertical-align:-20%;" class="tex" alt="\Delta x.\Delta p \approx 4\hbar" />, approximately an order of magnitude bigger than the quantum mechanical limit.</p>
<p>Through more rigorous statistical arguments, related to the spatial resolution and the expected momentum transferred, it may possible to derive the Heisenberg uncertainty principle through this line of reasoning.</p>
<p>If we consider the philosophical view that our reality is a cognitive model of our perceptual stimuli (which is the only view that makes sense to me), my fourth interpretation of the uncertainty principle being a cognitive limitation also holds a bit of water.</td>
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<td><span style="color: #ffffff;">About the Author</span><br />
<span style="color: #ffffff;"><br />
The author is a scientist from the European Organization for Nuclear Research (CERN), who currently works as a senior quantitative professional at Standard Chartered in Singapore. More information about the author can be found at his blog: http//www.Thulasidas.com. The views expressed in this column are only his personal views, which have not been influenced by considerations of the firm&#8217;s business or client relationships.<br />
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		<title>What is Space?</title>
		<link>http://www.thulasidas.com/2008-11/what-is-space.htm</link>
		<comments>http://www.thulasidas.com/2008-11/what-is-space.htm#comments</comments>
		<pubDate>Sun, 09 Nov 2008 05:36:16 +0000</pubDate>
		<dc:creator>Manoj</dc:creator>
				<category><![CDATA[Debates]]></category>
		<category><![CDATA[philosophy]]></category>
		<category><![CDATA[physics]]></category>
		<category><![CDATA[Albert Einstein]]></category>
		<category><![CDATA[perception]]></category>
		<category><![CDATA[realism]]></category>
		<category><![CDATA[realness]]></category>
		<category><![CDATA[space and time]]></category>
		<category><![CDATA[worldview]]></category>

		<guid isPermaLink="false">http://www.thulasidas.com/?p=605</guid>
		<description><![CDATA[This post examines the realness of our space perception. (Why did you think this blog was called Unreal?)  <a href="http://www.thulasidas.com/2008-11/what-is-space.htm">Continue reading <span class="meta-nav">&#8594;</span></a>]]></description>
			<content:encoded><![CDATA[<p>This sounds like a strange question. We all know what space is, it is all around us. When we open our eyes, we see it. If seeing is believing, then the question &#8220;What is space?&#8221; indeed is a strange one.</p>
<p>To be fair, we don&#8217;t actually see space. We see only objects which we assume are in space. Rather, we define space as whatever it is that holds or contains the objects. It is the arena where objects do their thing, the backdrop of our experience. In other words, experience presupposes space and time, and provides the basis for the worldview behind the currently popular interpretations of scientific theories.</p>
<p>Although not obvious, this definition (or assumption or understanding) of space comes with a philosophical baggage &#8212; that of realism. The realist&#8217;s view is predominant in the current understanding of Einstien&#8217;s theories as well. But Einstein himself may not have embraced realism blindly.  Why else would he say:</p>
<p><script type="text/javascript"><!--
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<p>In order to break away from the grip of realism, we have to approach the question tangentially. One way to do it is by studying the neuroscience and cognitive basis of sight, which after all provides the strongest evidence to the realness of space. Space, by and large, is the experience associated with sight. Another way is to examine experiential correlates of other senses: What is sound? </p>
<p>When we hear something, what we hear is, naturally, sound. We experience a tone, an intensity and a time variation that tell us a lot about who is talking, what is breaking and so on. But even after stripping off all the extra richness added to the experience by our brain, the most basic experience is still a &#8220;sound.&#8221; We all know what it is, but we cannot explain it in terms more basic than that.</p>
<p>Now let&#8217;s look at the sensory signal responsible for hearing. As we know, these are pressure waves in the air that are created by a vibrating body making compressions and depressions in the air around it. Much like the ripples in a pond, these pressure waves propagate in almost all directions. They are picked up by our ears. By a clever mechanism, the ears perform a spectral analysis and send electric signals, which roughly correspond to the frequency spectrum of the waves, to our brain. Note that, so far, we have a vibrating body, bunching and spreading of air molecules, and an electric signal that contains information about the pattern of the air molecules. We do not have sound yet.</p>
<p>The experience of sound is the magic our brain performs. It translates the electrical signal encoding the air pressure wave patterns to a representation of tonality and richness of sound. Sound is not the intrinsic property of a vibrating body or a falling tree, it is the way our brain chooses to represent the vibrations or, more precisely, the electrical signal encoding the spectrum of the pressure waves.</p>
<p>Doesn&#8217;t it make sense to call sound an internal cognitive representation of our auditory sensory inputs? If you agree, then reality itself is our internal representation of our sensory inputs. This notion is actually much more profound that it first appears. If sound is representation, so is smell. So is space.</p>
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<td width="500"><small>Figure: Illustration of the process of brain’s representation of sensory inputs. Odors are a representation of the chemical compositions and concentration levels our nose senses. Sounds are a mapping of the air pressure waves produced by a vibrating object. In sight, our representation is space, and possibly time. However, we do not know what it is the representation of.</small></td>
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</table>
<p>We can examine it and fully understand sound because of one remarkable fact &#8212; we have a more powerful sense, namely our sight. Sight enables us to understand the sensory signals of hearing and compare them to our sensory experience. In effect, sight enables us to make a model describing what sound is.</p>
<p>Why is it that we do not know the physical cause behind space? After all, we know of the causes behind the experiences of smell, sound, etc. The reason for our inability to see beyond the visual reality is in the hierarchy of senses, best illustrated using an example. Let&#8217;s consider a small explosion, like a firecracker going off. When we experience this explosion, we will see the flash, hear the report, smell the burning chemicals and feel the heat, if we are close enough.</p>
<p>The qualia of these experiences are attributed to the same physical event &#8212; the explosion, the physics of which is well understood. Now, let&#8217;s see if we can fool the senses into having the same experiences, in the absence of a real explosion. The heat and the smell are fairly easy to reproduce. The experience of the sound can also be created using, for instance, a high-end home theater system. How do we recreate the experience of the sight of the explosion? A home theater experience is a poor reproduction of the real thing.</p>
<p>In principle at least, we can think of futuristic scenarios such as the holideck in Star Trek, where the experience of the sight can be recreated. But at the point where sight is also recreated, is there a difference between the real experience of the explosion and the holideck simulation? The blurring of the sense of reality when the sight experience is simulated indicates that sight is our most powerful sense, and we have no access to causes beyond our visual reality.</p>
<p>Visual perception is the basis of our sense of reality. All other senses provide corroborating or complementing perceptions to the visual reality.</p>
<p>[This post has borrowed quite a bit from <a href="http://www.thulasidas.com/about/about-my-book">my book</a>.]</p>
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		<title>Light Travel Time Effects and Cosmological Features</title>
		<link>http://www.thulasidas.com/2008-11/light-travel-time-effects-and-cosmological-features.htm</link>
		<comments>http://www.thulasidas.com/2008-11/light-travel-time-effects-and-cosmological-features.htm#comments</comments>
		<pubDate>Fri, 07 Nov 2008 23:04:44 +0000</pubDate>
		<dc:creator>Manoj</dc:creator>
				<category><![CDATA[Articles and Essays]]></category>
		<category><![CDATA[philosophy]]></category>
		<category><![CDATA[physics]]></category>
		<category><![CDATA[Science]]></category>
		<category><![CDATA[Unpublished]]></category>
		<category><![CDATA[causality]]></category>
		<category><![CDATA[cosmic microwave background]]></category>
		<category><![CDATA[expanding universe]]></category>
		<category><![CDATA[gamma ray bursts]]></category>
		<category><![CDATA[grb]]></category>
		<category><![CDATA[light travel time]]></category>
		<category><![CDATA[microwave background radiation]]></category>
		<category><![CDATA[neuroscience]]></category>
		<category><![CDATA[perception]]></category>
		<category><![CDATA[perceptual constraints]]></category>
		<category><![CDATA[phenomenalism]]></category>
		<category><![CDATA[radio sources]]></category>
		<category><![CDATA[relativity]]></category>
		<category><![CDATA[space and time]]></category>
		<category><![CDATA[speed of light]]></category>
		<category><![CDATA[universe]]></category>

		<guid isPermaLink="false">http://www.thulasidas.com/?p=594</guid>
		<description><![CDATA[This unpublished article is a sequel to my earlier paper (also posted as Are Radio Sources and Gamma Ray Bursts Luminal Booms?).  This blog version contains the abstract, introduction and conclusions. The full version of the article is available as a PDF file. <a href="http://www.thulasidas.com/2008-11/light-travel-time-effects-and-cosmological-features.htm">Continue reading <span class="meta-nav">&#8594;</span></a>]]></description>
			<content:encoded><![CDATA[<p>This unpublished article is a sequel to my earlier paper (also posted here as &#8220;<a href="http://www.thulasidas.com/2008-11/are-radio-sources-and-gamma-ray-bursts-luminal-booms.htm">Are Radio Sources and Gamma Ray Bursts Luminal Booms?</a>&#8220;).  This blog version contains the abstract, introduction and conclusions. The full version of the article is available as a PDF file.</p>
<p><script type="text/javascript"><!--
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<p><em><strong>Abstract</strong></em></p>
<p><em>Light travel time effects (LTT) are an optical manifestation of the finite speed of light. They can also be considered perceptual constraints to the cognitive picture of space and time. Based on this interpretation of LTT effects, we recently presented a new hypothetical model for the temporal and spatial variation of the spectrum of Gamma Ray Bursts (GRB) and radio sources. In this article, we take the analysis further and show that LTT effects can provide a good framework to describe such cosmological features as the redshift observation of an expanding universe, and the cosmic microwave background radiation.  The unification of these seemingly distinct phenomena at vastly different length and time scales, along with its conceptual simplicity, can be regarded as indicators of the curious usefulness of this framework, if not its validity.</em></p>
<h4>Introduction</h4>
<p>The finite speed of light plays an important part in how we perceive distance and speed. This fact should hardly come as a surprise because we do know that things are not as we see them. The sun that we see, for instance, is already eight minutes old by the time we see it. This delay is trivial; if we want to know what is going on at the sun now, all we have to do is to wait for eight minutes. We, nonetheless, have to &#8220;correct&#8221; for this distortion in our perception due to the finite speed of light before we can trust what we see.</p>
<p>What is surprising (and seldom highlighted) is that when it comes to sensing motion, we cannot back-calculate the same way we take out the delay in seeing the sun. If we see a celestial body moving at an improbably high speed, we cannot figure out how fast and in what direction it is &#8220;really&#8221; moving without making further assumptions. One way of handling this difficulty is to ascribe the distortions in our perception of motion to the fundamental properties of the arena of physics &#8212; space and time. Another course of action is to accept the disconnection between our perception and the underlying &#8220;reality&#8221; and deal with it in some way.</p>
<p>Exploring the second option, we assume an underlying reality that gives rise to our perceived picture. We further model this underlying reality as obeying classical mechanics, and work out our perceived picture through the apparatus of perception. In other words, we do not attribute the manifestations of the finite speed of light to the properties of the underlying reality. Instead, we work out our perceived picture that this model predicts and verify whether the properties we do observe can originate from this perceptual constraint.</p>
<p>Space, the objects in it, and their motion are, by and large, the product of optical perception. One tends to take it for granted that perception arises from reality as one perceives it. In this article, we take the position that what we perceive is an incomplete or distorted picture of an underlying reality. Further, we are trying out classical mechanics for the the underlying reality (for which we use terms like absolute, noumenal or physical reality) that does cause our perception to see if it fits with our perceived picture (which we may refer to as sensed or phenomenal reality).</p>
<p>Note that we are not implying that the manifestations of perception are mere delusions. They are not; they are indeed part of our sensed reality because reality is an end result of perception. This insight may be behind Goethe&#8217;s famous statement, &#8220;Optical illusion is optical truth.&#8221;</p>
<p>We applied this line of thinking to a physics problem recently. We looked at the spectral evolution of a GRB and found it to be remarkably similar to that in a sonic boom. Using this fact, we presented a model for GRB as our perception of a &#8220;luminal&#8221; boom, with the understanding that it is our perceived picture of reality that obeys Lorentz invariance and our model for the underlying reality (causing the perceived picture) may violate relativistic physics. The striking agreement between the model and the observed features, however, extended beyond GRBs to symmetric radio sources, which can also be regarded as perceptual effects of hypothetical luminal booms.</p>
<p>In this article, we look at other implications of the model. We start with the similarities between the light travel time (LTT) effects and the coordinate transformation in Special Relativity (SR). These similarities are hardly surprising because SR is derived partly based on LTT effects. We then propose an interpretation of SR as a formalization of LTT effects and study a few observed cosmological phenomena in the light of this interpretation.</p>
<h4>Similarities between Light Travel Time Effects and SR</h4>
<p>Special relativity seeks a linear coordinate transformation between coordinate systems in motion with respect to each other.  We can trace the origin of linearity to a hidden assumption on the nature of space and time built into SR, as stated by Einstein: &#8220;In the first place it is clear that the equations must be linear on account of the properties of homogeneity which we attribute to space and time.&#8221;  Because of this assumption of linearity, the original derivation of the transformation equations ignores the asymmetry between approaching and receding objects.  Both approaching and receding objects can be described by two coordinate systems that are always receding from each other.  For instance, if a system <img src="http://l.wordpress.com/latex.php?latex=K&#038;bg=FFFFFF&#038;fg=000000&#038;s=0" title="K" style="vertical-align:-20%;" class="tex" alt="K" /> is moving with respect to another system <img src="http://l.wordpress.com/latex.php?latex=k&#038;bg=FFFFFF&#038;fg=000000&#038;s=0" title="k" style="vertical-align:-20%;" class="tex" alt="k" /> along the positive X axis of <img src="http://l.wordpress.com/latex.php?latex=k&#038;bg=FFFFFF&#038;fg=000000&#038;s=0" title="k" style="vertical-align:-20%;" class="tex" alt="k" />, then an object at rest in <img src="http://l.wordpress.com/latex.php?latex=K&#038;bg=FFFFFF&#038;fg=000000&#038;s=0" title="K" style="vertical-align:-20%;" class="tex" alt="K" /> at a positive <img src="http://l.wordpress.com/latex.php?latex=x&#038;bg=FFFFFF&#038;fg=000000&#038;s=0" title="x" style="vertical-align:-20%;" class="tex" alt="x" /> is receding while another object at a negative <img src="http://l.wordpress.com/latex.php?latex=x&#038;bg=FFFFFF&#038;fg=000000&#038;s=0" title="x" style="vertical-align:-20%;" class="tex" alt="x" /> is approaching an observer at the origin of <img src="http://l.wordpress.com/latex.php?latex=k&#038;bg=FFFFFF&#038;fg=000000&#038;s=0" title="k" style="vertical-align:-20%;" class="tex" alt="k" />.</p>
<p>The coordinate transformation in Einstein&#8217;s original paper is derived, in part, a manifestation of the light travel time (LTT) effects and the consequence of imposing the constancy of light speed in all inertial frames.  This is most obvious in the first thought experiment, where observers moving with a rod find their clocks not synchronized due to the difference in light travel times along the length of the rod. However, in the current interpretation of SR, the coordinate transformation is considered a basic property of space and time.</p>
<p>One difficulty that arises from this interpretation of SR is that the definition of the relative velocity between the two inertial frames becomes ambiguous.  If it is the velocity of the moving frame as measured by the observer, then the observed superluminal motion in radio jets starting from the core region becomes a violation of SR. If it is a velocity that we have to deduce by considering LT effects, then we have to employ the extra ad-hoc assumption that superluminality is forbidden.  These difficulties suggest that it may be better to disentangle the light travel time effects from the rest of SR.</p>
<p>In this section, we will consider space and time as a part of the cognitive model created by the brain, and argue that special relativity applies to the cognitive model.  The absolute reality (of which the SR-like space-time is our perception) does not have to obey the restrictions of SR.  In particular, objects are not restricted to subluminal speeds, but they may appear to us as though they are restricted to subluminal speeds in our perception of space and time. If we disentangle LTT effects from the rest of SR, we can understand a wide array of phenomena, as we shall see in this article.</p>
<p>Unlike SR, considerations based on LTT effects result in intrinsically different set of transformation laws for objects approaching an observer and those receding from him. More generally, the transformation depends on the angle between the velocity of the object and the observer&#8217;s line of sight. Since the transformation equations based on LTT effects treat approaching and receding objects asymmetrically, they provide a natural solution to the twin paradox, for instance.</p>
<p><script type="text/javascript"><!--
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<h4>Conclusions</h4>
<p>Because space and time are a part of a reality created out of light inputs to our eyes, some of their properties are manifestations of LTT effects, especially on our perception of motion.  The absolute, physical reality presumably generating the light inputs does not have to obey the properties we ascribe to our perceived space and time.</p>
<p>We showed that LTT effects are qualitatively identical to those of SR, noting that SR only considers frames of reference receding from each other.  This similarity is not surprising because the coordinate transformation in SR is derived based partly on LTT effects, and partly on the assumption that light travels at the same speed with respect to all inertial frames.  In treating it as a manifestation of LTT, we did not address the primary motivation of SR, which is a covariant formulation of Maxwell&#8217;s equations. It may be possible to disentangle the covariance of electrodynamics from the coordinate transformation, although it is not attempted in this article.</p>
<p>Unlike SR, LTT effects are asymmetric.  This asymmetry provides a resolution to the twin paradox and an interpretation of the assumed causality violations associated with superluminality.  Furthermore, the perception of superluminality is modulated by LTT effects, and explains <img src="http://l.wordpress.com/latex.php?latex=%5Cgamma&#038;bg=FFFFFF&#038;fg=000000&#038;s=0" title="\gamma" style="vertical-align:-20%;" class="tex" alt="\gamma" /> ray bursts and symmetric jets. As we showed in the article, perception of superluminal motion also holds an explanation for cosmological phenomena like the expansion of the universe and cosmic microwave background radiation.  LTT effects should be considered as a fundamental constraint in our perception, and consequently in physics, rather than as a convenient explanation for isolated phenomena.</p>
<p>Given that our perception is filtered through LTT effects, we have to deconvolute them from our perceived reality in order to understand the nature of the absolute, physical reality.  This deconvolution, however, results in multiple solutions.  Thus, the absolute, physical reality is beyond our grasp, and any <em>assumed</em> properties of the absolute reality can only be validated through how well the resultant <em>perceived</em> reality agrees with our observations.  In this article, we assumed that the underlying reality obeys our intuitively obvious classical mechanics and asked the question how such a reality would be perceived when filtered through light travel time effects. We demonstrated that this particular treatment could explain certain astrophysical and cosmological phenomena that we observe.</p>
<p>The coordinate transformation in SR can be viewed as a redefinition of space and time (or, more generally, reality) in order to accommodate the distortions in our perception of motion due to light travel time effects.  One may be tempted to argue that SR applies to the &#8220;real&#8221; space and time, not our perception.  This line of argument begs the question, what is real?  Reality is only a cognitive model created in our brain starting from our sensory inputs, visual inputs being the most significant.  Space itself is a part of this cognitive model. The properties of space are a mapping of the constraints of our perception.</p>
<p>The choice of accepting our perception as a true image of reality and redefining space and time as described in special relativity indeed amounts to a philosophical choice.  The alternative presented in the article is inspired by the view in modern neuroscience that reality is a cognitive model in the brain based on our sensory inputs.  Adopting this alternative reduces us to guessing the nature of the absolute reality and comparing its predicted projection to our real perception. It may simplify and elucidate some theories in physics and explain some puzzling phenomena in our universe.  However, this option is yet another philosophical stance against the unknowable absolute reality.</p>
<p><script type="text/javascript"><!--
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		<title>Are Radio Sources and Gamma Ray Bursts Luminal Booms?</title>
		<link>http://www.thulasidas.com/2008-11/are-radio-sources-and-gamma-ray-bursts-luminal-booms.htm</link>
		<comments>http://www.thulasidas.com/2008-11/are-radio-sources-and-gamma-ray-bursts-luminal-booms.htm#comments</comments>
		<pubDate>Thu, 06 Nov 2008 23:04:27 +0000</pubDate>
		<dc:creator>Manoj</dc:creator>
				<category><![CDATA[Articles and Essays]]></category>
		<category><![CDATA[physics]]></category>
		<category><![CDATA[Science]]></category>
		<category><![CDATA[AGN]]></category>
		<category><![CDATA[Doppler shift]]></category>
		<category><![CDATA[galaxy]]></category>
		<category><![CDATA[grb afterglow]]></category>
		<category><![CDATA[Lorentz invariance]]></category>
		<category><![CDATA[perception]]></category>
		<category><![CDATA[radio sources]]></category>
		<category><![CDATA[relativity]]></category>
		<category><![CDATA[sonic boom]]></category>

		<guid isPermaLink="false">http://www.thulasidas.com/?p=577</guid>
		<description><![CDATA[This post is the blog version of my article published in the International Journal of Modern Physics D (IJMP-D) in 2007, soon to become the Top Accessed Article of the journal by Jan 2008. Although it might seem like a hard core physics article, it is in fact an application of the philosophical insight permeating this blog and my book.  <a href="http://www.thulasidas.com/2008-11/are-radio-sources-and-gamma-ray-bursts-luminal-booms.htm">Continue reading <span class="meta-nav">&#8594;</span></a>]]></description>
			<content:encoded><![CDATA[<p>This article was published in the International Journal of Modern Physics D (IJMP&#8211;D) in 2007.  It soon became the <a href="javascript:popUpFat('http://www.worldscinet.com/ijmpd/mkt/top.shtml')">Top Accessed Article</a> of the journal by <a href="javascript:popUpFat('img/ijmpd-top.gif')">Jan 2008</a>. </p>
<p>Although it might seem like a hard core physics article, it is in fact an application of the philosophical insight permeating this blog and my book. </p>
<p>This blog version contains the abstract, introduction and conclusions. The full version of the article is available as a PDF file.</p>
<p>Journal Reference: <a href="javascript:popUpFat('http://ejournals.wspc.com.sg/ijmpd/16/1606/S0218271807010559.html')">IJMP-D Vol. 16, No. 6 (2007) pp. 983&ndash;1000</a>.</p>
<p><script type="text/javascript"><!--
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<p><em><strong>Abstract</strong></em></p>
<p><em>The softening of the GRB afterglow bears remarkable similarities to the frequency evolution in a sonic boom. At the front end of the sonic boom cone, the frequency is infinite, much like a Gamma Ray Burst (GRB).  Inside the cone, the frequency rapidly decreases to infrasonic ranges and the sound source appears at two places at the same time, mimicking the double-lobed radio sources.  Although a &#8220;luminal&#8221; boom violates the Lorentz invariance and is therefore forbidden, it is tempting to work out the details and compare them with existing data.  This temptation is further enhanced by the observed superluminality in the celestial objects associated with radio sources and some GRBs.  In this article, we calculate the temporal and spatial variation of observed frequencies from a hypothetical luminal boom and show remarkable similarity between our calculations and current observations.</em></p>
<h4>Introduction</h4>
<p>A sonic boom is created when an object emitting sound passes through the medium faster than the speed of sound in that medium. As the object traverses the medium, the sound it emits creates a conical wavefront, as shown in Figure 1.  The sound frequency at this wavefront is infinite because of the Doppler shift.  The frequency behind the conical wavefront drops dramatically and soon reaches the infrasonic range.  This frequency evolution is remarkably similar to afterglow evolution of a gamma ray burst (GRB).</p>
<table border="0" width="500" align="center">
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<td><img src="/img/ijmpd-figure1.png" alt="Figure 1" hspace="4" vspace="20" align="left" /></td>
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<td width="500"><small>Figure <a name="Supersonic">1</a>:. The frequency evolution of sound waves as a result of the Doppler effect in supersonic motion.  The supersonic object S is moving along the arrow.  The sound waves are &#8220;inverted&#8221; due to the motion, so that the waves emitted at two different points in the trajectory merge and reach the observer (at O) at the same time.  When the wavefront hits the observer, the frequency is infinity. After that, the frequency rapidly decreases.</small></td>
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<p>Gamma Ray Bursts are very brief, but intense flashes of <img src="http://l.wordpress.com/latex.php?latex=%5Cgamma&#038;bg=FFFFFF&#038;fg=000000&#038;s=0" title="\gamma" style="vertical-align:-20%;" class="tex" alt="\gamma" /> rays in the sky, lasting from a few milliseconds to several minutes, and are currently believed to emanate from cataclysmic stellar collapses.  The short flashes (the prompt emissions) are followed by an afterglow of progressively softer energies. Thus, the initial <img src="http://l.wordpress.com/latex.php?latex=%5Cgamma&#038;bg=FFFFFF&#038;fg=000000&#038;s=0" title="\gamma" style="vertical-align:-20%;" class="tex" alt="\gamma" /> rays are promptly replaced by X-rays, light and even radio frequency waves. This softening of the spectrum has been known for quite some time, and was first described using a hypernova (fireball) model.  In this model, a relativistically expanding fireball produces the <img src="http://l.wordpress.com/latex.php?latex=%5Cgamma&#038;bg=FFFFFF&#038;fg=000000&#038;s=0" title="\gamma" style="vertical-align:-20%;" class="tex" alt="\gamma" /> emission, and the spectrum softens as the fireball cools down.  The model calculates the energy released in the <img src="http://l.wordpress.com/latex.php?latex=%5Cgamma&#038;bg=FFFFFF&#038;fg=000000&#038;s=0" title="\gamma" style="vertical-align:-20%;" class="tex" alt="\gamma" /> region as <img src="http://l.wordpress.com/latex.php?latex=10%5E%7B53%7D&#038;bg=FFFFFF&#038;fg=000000&#038;s=0" title="10^{53}" style="vertical-align:-20%;" class="tex" alt="10^{53}" />&#8211;<img src="http://l.wordpress.com/latex.php?latex=10%5E%7B54%7D&#038;bg=FFFFFF&#038;fg=000000&#038;s=0" title="10^{54}" style="vertical-align:-20%;" class="tex" alt="10^{54}" /> ergs in a few seconds.  This energy output is similar to about 1000 times the total energy released by the sun over its entire lifetime.</p>
<p>More recently, an inverse decay of the peak energy with varying time constant has been used to empirically fit the observed time evolution of the peak energy using a collapsar model.  According to this model, GRBs are produced when the energy of highly relativistic flows in stellar collapses are dissipated, with the resulting radiation jets angled properly with respect to our line of sight.  The collapsar model estimates a lower energy output because the energy release is not isotropic, but concentrated along the jets. However, the rate of the collapsar events has to be corrected for the fraction of the solid angle within which the radiation jets can appear as GRBs.  GRBs are observed roughly at the rate of once a day.  Thus, the expected rate of the cataclysmic events powering the GRBs is of the order of <img src="http://l.wordpress.com/latex.php?latex=10%5E4&#038;bg=FFFFFF&#038;fg=000000&#038;s=0" title="10^4" style="vertical-align:-20%;" class="tex" alt="10^4" />&#8211;<img src="http://l.wordpress.com/latex.php?latex=10%5E6&#038;bg=FFFFFF&#038;fg=000000&#038;s=0" title="10^6" style="vertical-align:-20%;" class="tex" alt="10^6" /> per day. Because of this inverse relationship between the rate and the estimated energy output, the total energy released per observed GRB remains the same.</p>
<p>If we think of a GRB as an effect similar to the sonic boom in supersonic motion, the assumed cataclysmic energy requirement becomes superfluous.  Another feature of our perception of supersonic object is that we hear the sound source at two different location as the same time, as illustrated in Figure 2. This curious effect takes place because the sound waves emitted at two different points in the trajectory of the supersonic object reach the observer at the same instant in time.  The end result of this effect is the perception of a symmetrically receding pair of sound sources, which, in the luminal world, is a good description of symmetric radio sources (Double Radio source Associated with Galactic Nucleus or DRAGN).</p>
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<td><img src="/img/ijmpd-figure2.png" alt="Figure 2" hspace="4" vspace="20" align="left" /></td>
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<td width="500"><small>Figure 2:. The object is flying from <img src="http://l.wordpress.com/latex.php?latex=A%27&#038;bg=FFFFFF&#038;fg=000000&#038;s=0" title="A'" style="vertical-align:-20%;" class="tex" alt="A'" /> to <img src="http://l.wordpress.com/latex.php?latex=A&#038;bg=FFFFFF&#038;fg=000000&#038;s=0" title="A" style="vertical-align:-20%;" class="tex" alt="A" /> through <img src="http://l.wordpress.com/latex.php?latex=B%27&#038;bg=FFFFFF&#038;fg=000000&#038;s=0" title="B'" style="vertical-align:-20%;" class="tex" alt="B'" /> and <img src="http://l.wordpress.com/latex.php?latex=B&#038;bg=FFFFFF&#038;fg=000000&#038;s=0" title="B" style="vertical-align:-20%;" class="tex" alt="B" /> at a constant supersonic speed. Imagine that the object emits sound during its travel. The sound emitted at the point <img src="http://l.wordpress.com/latex.php?latex=B%27&#038;bg=FFFFFF&#038;fg=000000&#038;s=0" title="B'" style="vertical-align:-20%;" class="tex" alt="B'" /> (which is near the point of closest approach <img src="http://l.wordpress.com/latex.php?latex=B&#038;bg=FFFFFF&#038;fg=000000&#038;s=0" title="B" style="vertical-align:-20%;" class="tex" alt="B" />) reaches the observer at <img src="http://l.wordpress.com/latex.php?latex=O&#038;bg=FFFFFF&#038;fg=000000&#038;s=0" title="O" style="vertical-align:-20%;" class="tex" alt="O" /> before the sound emitted earlier at <img src="http://l.wordpress.com/latex.php?latex=A%27&#038;bg=FFFFFF&#038;fg=000000&#038;s=0" title="A'" style="vertical-align:-20%;" class="tex" alt="A'" />.  The instant when the sound at an earlier point <img src="http://l.wordpress.com/latex.php?latex=A%27&#038;bg=FFFFFF&#038;fg=000000&#038;s=0" title="A'" style="vertical-align:-20%;" class="tex" alt="A'" /> reaches the observer, the sound emitted at a much later point <img src="http://l.wordpress.com/latex.php?latex=A&#038;bg=FFFFFF&#038;fg=000000&#038;s=0" title="A" style="vertical-align:-20%;" class="tex" alt="A" /> also reaches <img src="http://l.wordpress.com/latex.php?latex=O&#038;bg=FFFFFF&#038;fg=000000&#038;s=0" title="O" style="vertical-align:-20%;" class="tex" alt="O" />.  So, the sound emitted at <img src="http://l.wordpress.com/latex.php?latex=A&#038;bg=FFFFFF&#038;fg=000000&#038;s=0" title="A" style="vertical-align:-20%;" class="tex" alt="A" /> and <img src="http://l.wordpress.com/latex.php?latex=A%27&#038;bg=FFFFFF&#038;fg=000000&#038;s=0" title="A'" style="vertical-align:-20%;" class="tex" alt="A'" /> reaches the observer at the same time, giving the impression that the object is at these two points at the same time.  In other words, the observer hears two objects moving away from <img src="http://l.wordpress.com/latex.php?latex=B%27&#038;bg=FFFFFF&#038;fg=000000&#038;s=0" title="B'" style="vertical-align:-20%;" class="tex" alt="B'" /> rather than one real object.</small></td>
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<p>Radio Sources are typically symmetric and seem associated with galactic cores, currently considered manifestations of space-time singularities or neutron stars.  Different classes of such objects associated with Active Galactic Nuclei (AGN) were found in the last fifty years.  Figure 3 shows the radio galaxy Cygnus A, an example of such a radio source and one of the brightest radio objects.  Many of its features are common to most extragalactic radio sources: the symmetric double lobes, an indication of a core, an appearance of jets feeding the lobes and the hotspots. Some researchers have reported more detailed kinematical features, such as the proper motion of the hotspots in the lobes.</p>
<p>Symmetric radio sources (galactic or extragalactic) and GRBs may appear to be completely distinct phenomena.  However, their cores show a similar time evolution in the peak energy, but with vastly different time constants.  The spectra of GRBs rapidly evolve from <img src="http://l.wordpress.com/latex.php?latex=%5Cgamma&#038;bg=FFFFFF&#038;fg=000000&#038;s=0" title="\gamma" style="vertical-align:-20%;" class="tex" alt="\gamma" /> region to an optical or even RF afterglow, similar to the spectral evolution of the hotspots of a radio source as they move from the core to the lobes.  Other similarities have begun to attract attention in the recent years.</p>
<p>This article explores the similarities between a hypothetical &#8220;luminal&#8221; boom and these two astrophysical phenomena, although such a luminal boom is forbidden by the Lorentz invariance. Treating GRB as a manifestation of a hypothetical luminal boom results in a model that unifies these two phenomena and makes detailed predictions of their kinematics.</p>
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<td><img src="/img/ijmpd-figure3.png" alt="Figure 3" hspace="4" vspace="20" align="left" /></td>
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<td width="500"><small>Figure 3:.The radio jet and lobes in the hyperluminous radio galaxy Cygnus A. The hotspots in the two lobes, the core region and the jets are clearly visible.  (Reproduced from an image courtesy of NRAO/AUI.)</small></td>
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<h4>Conclusions</h4>
<p>In this article, we looked at the spatio-temporal evolution of a supersonic object (both in its position and the sound frequency we hear).  We showed that it closely resembles GRBs and DRAGNs if we were to extend the calculations to light, although a luminal boom would necessitate superluminal motion and is therefore forbidden.</p>
<p>This difficulty notwithstanding, we presented a unified model for Gamma Ray Bursts and jet like radio sources based on bulk superluminal motion.  We showed that a single superluminal object flying across our field of vision would appear to us as the symmetric separation of two objects from a fixed core. Using this fact as the model for symmetric jets and GRBs, we explained their kinematic features quantitatively. In particular, we showed that the angle of separation of the hotspots was parabolic in time, and the redshifts of the two hotspots were almost identical to each other. Even the fact that the spectra of the hotspots are in the radio frequency region is explained by assuming hyperluminal motion and the consequent redshift of the black body radiation of a typical star.  The time evolution of the black body radiation of a superluminal object is completely consistent with the softening of the spectra observed in GRBs and radio sources. In addition, our model explains why there is significant blue shift at the core regions of radio sources, why radio sources seem to be associated with optical galaxies and why GRBs appear at random points with no advance indication of their impending appearance.</p>
<p>Although it does not address the energetics issues (the origin of superluminality), our model presents an intriguing option based on how we would perceive hypothetical superluminal motion.  We presented a set of predictions and compared them to existing data from DRAGNs and GRBs. The features such as the blueness of the core, symmetry of the lobes, the transient <img src="http://l.wordpress.com/latex.php?latex=%5Cgamma&#038;bg=FFFFFF&#038;fg=000000&#038;s=0" title="\gamma" style="vertical-align:-20%;" class="tex" alt="\gamma" /> and X-Ray bursts, the measured evolution of the spectra along the jet all find natural and simple explanations in this model as perceptual effects.  Encouraged by this initial success, we may accept our model based on luminal boom as a working model for these astrophysical phenomena.</p>
<p>It has to be emphasized that perceptual effects can masquerade as apparent violations of traditional physics.  An example of such an effect is the apparent superluminal motion, which was explained and anticipated within the context of the special theory of relativity even before it was actually observed.  Although the observation of superluminal motion was the starting point behind the work presented in this article, it is by no means an indication of the validity of our model.  The similarity between a sonic boom and a hypothetical luminal boom in spatio-temporal and spectral evolution is presented here as a curious, albeit probably unsound, foundation for our model.</p>
<p>One can, however, argue that the special theory of relativity (SR) does not deal with superluminality and, therefore, superluminal motion and luminal booms are not inconsistent with SR.  As evidenced by the opening statements of Einstein’s original paper, the primary motivation for SR is a covariant formulation of Maxwell’s equations, which requires a coordinate transformation derived based partly on light travel time (LTT) effects, and partly on the assumption that light travels at the same speed with respect to all inertial frames.  Despite this dependence on LTT, the LTT effects are currently assumed to apply on a space-time that obeys SR.  SR is a redefinition of space and time (or, more generally, reality) in order to accommodate its two basic postulates. It may be that there is a deeper structure to space-time, of which SR is only our perception, filtered through the LTT effects. By treating them as an optical illusion to be applied on a space-time that obeys SR, we may be double counting them. We may avoid the double counting by disentangling the covariance of Maxwell’s equations from the coordinate transformations part of SR. Treating the LTT effects separately (without attributing their consequences to the basic nature of space and time), we can accommodate superluminality and obtain elegant explanations of the astrophysical phenomena described in this article. Our unified explanation for GRBs and symmetric radio sources, therefore, has implications as far reaching as our basic understanding of the nature of space and time.</p>
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		<title>The Big Bang Theory</title>
		<link>http://www.thulasidas.com/2008-10/the-big-bang-theory.htm</link>
		<comments>http://www.thulasidas.com/2008-10/the-big-bang-theory.htm#comments</comments>
		<pubDate>Mon, 20 Oct 2008 23:28:20 +0000</pubDate>
		<dc:creator>Manoj</dc:creator>
				<category><![CDATA[physics]]></category>
		<category><![CDATA[big bang theory]]></category>
		<category><![CDATA[black hole]]></category>
		<category><![CDATA[galaxy]]></category>
		<category><![CDATA[little universe]]></category>
		<category><![CDATA[relativity]]></category>
		<category><![CDATA[singularity concept]]></category>
		<category><![CDATA[Steven Weinberg]]></category>

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		<description><![CDATA[People present the Big Bang theory in physics pretty much like Evolution in biology. But I feel that it is disingenuous to do that. To me, it looks as though the Big Bang theory is so full of patchwork, such a mathematical collage to cook up something that is consistent with GR that it is hard to imagine that it corresponds to anything real. Here is a short list of my trouble with the theory. <a href="http://www.thulasidas.com/2008-10/the-big-bang-theory.htm">Continue reading <span class="meta-nav">&#8594;</span></a>]]></description>
			<content:encoded><![CDATA[<p>I am a physicist, but I don&#8217;t quite understand the Big Bang theory. Let me tell you why.</p>
<p>The Big Bang theory says that the whole universe started from a &#8220;singularity&#8221; &#8212; a single point. The first question then is, a single point where? It is not a single point &#8220;in space&#8221; because the whole space was a single point. The Discovery channel would put it fancifully that &#8220;the whole universe could fit in the palm of your hand,&#8221; which of course it could not. Your palm would also be a little palm inside the little universe in that single point.</p>
<p>The second question is, if the whole universe was inside one point, what about all the points around it? Physicists would advise you not to ask such stupid questions. Don&#8217;t feel bad, they have <a href="http://www.thulasidas.com/2007-03/universe-size-and-age.htm">asked me to shut up as well</a>. Some of them may kindly explain that the other points may be parallel universes. Others may say that there are no &#8220;other&#8221; points. They may point out (as Steven Weinberg does in The Dreams of a Final Theory) that there is nothing more to the north of the North Pole. I consider this analogy more of a semantic argument than a scientific one, but let&#8217;s buy this argument for now.</p>
<p>The next hurdle is that the singularity is in space-time &#8212; not merely in space. So before the Big Bang, there was no time. Sorry, there was no &#8220;before!&#8221; This is a concept that my five year old son has problems with. Again, the Big Bang cosmologist will point out that things do not necessarily have to continue backwards &#8212; you may think that whatever temperature something is at, you can always make it a little colder. But you cannot make it colder than absolute zero. True, true; but is temperature the same as time?  Temperature is a measure of hotness, which is an aggregate of molecular speeds. And speed is distance traveled in unit time. Time again. Hmmm&#8230;.</p>
<p>I am sure it is my lack of imagination or incompleteness of training that is preventing me from understanding and accepting this Big Bang concept. But even after buying the space-time singularity concept, other difficulties persist.</p>
<p>Firstly, if the whole universe is at one point at one time, one would naively expect it to make a super-massive black hole from which not even light can escape. Clearly then, the whole universe couldn&#8217;t have banged out of that point. But I&#8217;m sure there is a perfectly logical explanation why it can, just that I don’t know it yet. May be some of my readers will point it out to me?</p>
<p>Second, what&#8217;s with dark matter and dark energy? The Big Bang cosmology has to stretch itself a bit with the notion of dark energy to account for the large scale dynamics of the observed universe. Our universe is expanding (or so it appears) at an accelerating rate, which can only be accounted for by assuming that there is an invisible energy pushing the galaxies apart. Within the galaxies themselves, stars are moving around as though there is more mass than we can see. This is the so called dark matter. Although &#8220;dark&#8221; signifies invisible, to me, it sounds as though we are in the dark about what these beasts are!</p>
<p>The third trouble I have is the fact that the Big Bang cosmology violates special relativity (SR). This little concern of mine has been answered in many different ways:</p>
<ul>
<li>One answer is that <a href="http://www.thulasidas.com/2007-03/universe-size-and-age.htm">general relativity &#8220;trumps&#8221; SR</a> &#8212; if there are conflicting predictions or directives from these two theories, I was advised to always trust GR.</li>
<li>Besides, SR applies only to local motion, like spaceships whizzing past each other. Non-local events do not have to obey SR. This makes me wonder how events know whether they are local or not. Well, that was bit tongue in cheek. I can kind of buy this argument (based on <a href="http://www.thulasidas.com/2006-11/of-rotation-lt-and-acceleration.htm">curvature of space-time</a> perhaps becoming significant at large distances), although the non-scientific nature of local-ness makes me uneasy. (During the inflationary phase in the Big Bang theory, were things local or non-local?)</li>
<li>Third answer: In the case of the Big Bang, the space itself is expanding, hence no violation of SR. SR applies to motion through space. (Wonder if I could&#8217;ve used that line when I got pulled over on I-81. &#8220;Officer, I wasn&#8217;t speeding. Just that space in between was expanding a little too fast!&#8221;)</li>
</ul>
<p>Speaking of space expanding, it is supposed to be expanding only in between galaxies, not within them, apparently. I&#8217;m sure there is a perfectly logical explanation why, probably related to the proximity of masses or whatnot, but I&#8217;m not well-versed enough to understand it. In physics, disagreement and skepticism are always due to ignorance. But it is true that I have no idea what they mean when they say the space itself is expanding. If I stood in a region where the space is expanding, would I become bigger and would galaxies look smaller to me?</p>
<p>Note that it is necessary for space to expand only between galaxies. If it expanded everywhere, from subatomic to galactic scales, it would look as though nothing changed. Hardly satisfying because the distant galaxies do look as though they are flying off at great speeds.</p>
<p>I guess the real question is, what exactly is the difference between space expanding between two galaxies and the two galaxies merely moving away from each other?</p>
<p>One concept that I find bizarre is that singularity doesn&#8217;t necessarily mean single point in space. It was <a href="http://www.thulasidas.com/2007-03/universe-size-and-age.htm">pointed out to me</a> that the Big Bang could have been a spread out affair &#8212; thinking otherwise was merely my misconception, because I got confused by the similarity between the words &#8220;singularity&#8221; and single.</p>
<p>People present the Big Bang theory in physics pretty much like Evolution in biology, implying the same level of infallibility. But I feel that it is disingenuous to do that. To me, it looks as though the theory is so full of patchwork, such a mathematical collage to cook up something that is consistent with GR that it is hard to imagine that it corresponds to anything real (ignoring, for the moment, my favorite question &#8212; <a href="http://www.thulasidas.com/2006-06/what-is-real.htm">what is real</a>?) But popular writers have embraced it. For instance, Ray Kurzweil and Richard Dawkins put it as a matter of fact in their books, lending it a credence that it perhaps doesn&#8217;t merit.</p>
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		<title>End of Evolution</title>
		<link>http://www.thulasidas.com/2008-09/end-of-evolution.htm</link>
		<comments>http://www.thulasidas.com/2008-09/end-of-evolution.htm#comments</comments>
		<pubDate>Sat, 06 Sep 2008 00:14:29 +0000</pubDate>
		<dc:creator>Manoj</dc:creator>
				<category><![CDATA[Science]]></category>
		<category><![CDATA[electromagnetic interaction]]></category>
		<category><![CDATA[evolution]]></category>
		<category><![CDATA[genes]]></category>
		<category><![CDATA[physics]]></category>

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		<description><![CDATA[Does evolution still work among human beings? Or, have we messed up the potential genetic advantages of random mutations to such an extent that we have stopped evolution on its track? <a href="http://www.thulasidas.com/2008-09/end-of-evolution.htm">Continue reading <span class="meta-nav">&#8594;</span></a>]]></description>
			<content:encoded><![CDATA[<p>To a physicist, life is a neat example of electromagnetic interaction.  To a biologist, however, life is a DNA replication algorithm. Let&#8217;s mull over the biology view for a few moments.</p>
<p>The genes in our body have only one motive&#8211;to get replicated.  Our body is created in accordance with a blue print encoded in the genes to &#8220;run&#8221; this algorithm.  How this algorithm gets mapped to our higher level goals and emotions is what life is all about to most people who are not physicists or biologists.</p>
<p>A simple mapping of this algorithm leads to the maxim in evolution &#8220;the survival of the fittest.&#8221;  Any mutation that has the tiniest advantage in terms of survivability gets amplified over time.  Similarly, all disadvantaged genes get wiped out.</p>
<p>But evolution in humans (and through our influence, the whole echo-system) has taken a new turn.  Survival of the fittest used to mean the survival of the strongest or the smartest.  For instance, if I had a genetic condition that made me prone to some life-threatening disease (in other words, if I was not very strong), my chances of passing on my genes would be a little smaller.</p>
<p>However, because of the advances in medicine, the survival chances for such disadvantaged genes are normalized to roughly the same level as those of the rest of the species.  Then again, because of the dependence of the quality of health care on money, the survival chances get distorted in favor of the rich. So, is the mapping of the DNA algorithm now &#8220;the survival of the richest?&#8221;</p>
<p>Wealth is considered a product of intelligence.  But intelligence (as defined by money-making ability) is not necessarily genetic.  It may be, but we do not know that yet.  So over several generations, it is not even the richest that survive, because time averages out the survival chances.</p>
<p>So what exactly is going to survive?</p>
<p>Ref: This post is an excerpt from my book, <a href="/about/about-my-book">The Unreal Universe.</a></p>
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