Κατηγορία Αρχεία: Αποσπάσματα

Αυτή η κατηγορία περιέχει συλλογισμοί μου για κυρίως διάσημο εισαγωγικά. Οι στοχασμοί συλλογίστηκε ειδικά για το Unreal Blog.

Bye Bye Einstein

Starting from his miraculous year of 1905, Einstein has dominated physics with his astonishing insights on space and time, and on mass and gravity. Αληθής, there have been other physicists who, with their own brilliance, have shaped and moved modern physics in directions that even Einstein couldn’t have foreseen; and I don’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’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.

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’s century is behind us now. Ξέρω, 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’s ideas go.

[animation]Let’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 (στο πάτωμα, that is). If the dot was moving faster than light, how would you see it? Καλά, you wouldn’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 — one before the first point, and one after. Έτσι, 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.).

[animation]Why did I start with this animation of how the illusion of a symmetric object can happen? Καλά, we see a lot of active symmetric structures in the universe. Για παράδειγμα, look at this picture of Cygnus A. There is a “core” from which seem to emanate “features” that float away to the “lobes.” Doesn’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 — because of Einstein. I know this — I tried to get my old physicist friends to consider this model. The response is always some variant of this, “Interesting, but it cannot work. It violates Lorentz invariance, έτσι δεν είναι?” LV being physics talk for Einstein’s insistence that nothing should go faster than light. Now that neutrinos can violate LV, why not me?

Φυσικά, 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, για παράδειγμα, emit radiation in the radio frequency range. Όντως, 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. Όντως, I managed to publish this model a while ago under the title, “Είναι Radio Πηγές και Gamma Ray Εκρήξεις Luminal Ομολογίες?“.

Μπορείτε να δείτε, 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. 🙂

Such long odds, Ωστόσο,, 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. (Όντως, light travel time effects will make it impossible to have a superluminal dot on a ceiling, as in my animation above — 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’t.) Αλλά, 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 “works” — as I made very clear in my previous post in this series.

Another philosophical problem with the theory is that it is not testable. Ξέρω, 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, για παράδειγμα), 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, “Ah, there is no problem here, the symmetry between the clocks is broken because of the acceleration.” People have argued back and forth about such thought experiments for an entire century, so I don’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.

Love of Wisdom

Philosophy means love wisdom. But it enjoys none of the glamor that its definition would imply. Για παράδειγμα, in one of the board games that I played with the kids recently, the chance card that would make you bankrupt actually read, “Turn into a philosopher and lose all your money!” This card was particularly troubling for me because I do plan to take up philosophy seriously, hopefully soon.

The lack of correlation between wisdom and worldly rewards is unsettling, especially to those who are foolish enough to consider themselves wise. Why is it that the love of wisdom wouldn’t translate to glory, riches and creature comforts? The reason, as far as I can tell, is a deep disconnect between philosophy and life — as a wise (but distinctly unphilosophical) friend of mine put it in one of those hazy late-night stupors of the graduate years, “Philosophy to real life is what masturbation is to sex.” Ναι, the masses see the love of wisdom as pointless intellectual masturbation. This view is perhaps echoed in what Russell said once:

Philosophy busies itself with things that seem obvious, to come up with something grandiose. This apparent obsession with trivialities is a false impression. Dispelling this impression is the purpose of this post. Let me start by pointing out one fact. Philosophy is at the root of everything that you do. You live a good, moral life? Or even a lousy, greedy one? Your behavior, choices and reasons are studied in Ethics. You are a quant, or do stuff technical or mathematical? Logic. Into physics and worship Einstein? You cannot then ignore the metaphysical aspects of χώρο και χρόνο. Lawyer? Ναι, Rhetorics. Knowledge worker? Epistemology defines what knowledge is. Artist? Fashion designer? Work in the movie industry? We got you covered in Aesthetics. Μπορείτε να δείτε, every avenue of human endeavor has a philosophic underpinning to it.

Pointing out this underpinning is, στην πραγματικότητα, not as big a deal as I make it out to be. It is merely a matter of definition. I define philosophy to be whatever it is that “underpins” all aspects of life, and then point out this underpinning as evidence of its importance. The real value of philosophy is in structuring our thoughts and guiding them, για παράδειγμα, in perceiving the speciousness and subtle circularity of my underpinning-therefore-important argument. Philosophy teaches us that nothing stands own its own, and that there are structures and schools of thought that illuminate questions that befuddle us. There are scaffolds to support us, and giants on whose shoulders we can stand to see far and clear. Για να είμαστε σίγουροι, some of these giants may be facing the wrong way, but it is again the boldness and independence that come with philosophy that will help us see the errors in their ways. Without it, learning becomes indoctrination, and in our quest to assimilate information into wisdom, we get stuck somewhere in between — perhaps at the level of knowledge.

All this discussion still doesn’t give us a clue as to the disquieting connection between philosophy and bankruptcy. For when a great man voices his existential anguish as, “Νομίζω ότι, Ως εκ τούτου, είμαι,” we can always say (as we often do), “Good for you mate, whatever works for you!” and go about our life.

Love of wisdom perhaps facilitates its acquisition, and the purpose of wisdom is only wisdom. It is very much like life, the purpose of which is merely to live a little longer. But without philosophy, how do we see the meaning of life? Or lack thereof?

Change the Facts

There is beauty in truth, and truth in beauty. Where does this link between truth and beauty come from? Φυσικά, beauty is subjective, and truth is objective — 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.

The beauty and perfection I’m thinking about are of a different kind — those of ideas and concepts. Μερικές φορές, 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:

But this conviction about the veracity of a theory based on its perfection is hardly enough. Einstein’s genius really is in his philosophical tenacity, his willingness to push the idea beyond what is considered logical.

Let’s take an example. Let’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, “Physical laws are independent of the state of motion of the experimental system.”

The physical laws Einstein chose to look at were Maxwell’s equations of electromagnetism, which had the speed of light appearing in them. For them to be independent of (or covariant with, να είναι πιο ακριβής) 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.

Τώρα, I don’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, καλά, so be it. That is the philosophical conviction and tenacity that I wanted to talk about — the kind that gave us Special Relativity about a one hundred years ago.

Want to get to General Relativity from here? Simple, just find another beautiful truth. Here is one… 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 (ή 32 ft/s/s), and it nullifies gravity. So gravity is the same as acceleration — voila, another beautiful principle.

World line of airplanesIn 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 — our cruising airplane, για παράδειγμα, 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, Ως εκ τούτου,, will have a curved world line, running from the slow world line to the fast one.

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 — just that you straighten the world-line calling it a geodesic and attribute the curvature to space-time instead.)

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. Μετά από όλα, he wanted to know God’s thoughts, not the details.

God’s Blunder

Scriptures tell us, in different ways depending on our denomination and affiliation, that God created the world and everything in it, including us. This is creationism in a nutshell.

Standing in the other corner, all gloved up to knock the daylight out of creationism, is science. It tells us that we came out of complete lifelessness through successive mutations goaded by the need to survive. This is Evolution, a view so widely accepted that the use of capital E is almost justified.

All our experience and knowledge point to the rightness the Evolution idea. It doesn’t totally preclude the validity of God, but it does make it more likely that we humans created God. (It must be just us humans for we don’t see a cat saying Lord’s grace before devouring a mouse!) Και, given the inconveniences caused by the God concept (wars, crusades, the dark ages, ethnic cleansing, religious riots, terrorism and so on), it certainly looks like a blunder.

No wonder Nietzsche said,

Από την άλλη πλευρά, if God did create man, then all the stupid things that we do — wars, crusades etc. plus this blog — do point to the fact that we are a blunder. We must be such a disappointment to our creator. Sorry Sir!

Φωτογραφία Η Βιβλιοθήκη του Κογκρέσου

Sex και Φυσική — Σύμφωνα με τον Feynman

Φυσική περνά από μια εποχή του εφησυχασμού μία φορά σε μια στιγμή. Εφησυχασμός προέρχεται από μια αίσθηση πληρότητας, ένα συναίσθημα που έχουμε ανακαλύψει τα πάντα είναι εκεί για να ξέρετε, η διαδρομή είναι σαφής και οι μέθοδοι καλά κατανοητό.

Ιστορικά, Οι εν λόγω περίοδοι του εφησυχασμού που ακολουθείται από τις ραγδαίες εξελίξεις που εντελώς τον τρόπο που η φυσική γίνεται, δείχνοντάς μας πόσο λάθος έχουμε. Το συγκινητικό μάθημα της ιστορίας είναι ίσως ό, τι σας ζητηθεί Φάινμαν να πω:

Μια τέτοια ηλικία του εφησυχασμού υπήρχε στο γύρισμα του 19ου αιώνα. Διάσημοι personas όπως Kelvin παρατήρησε ότι το μόνο που έμενε να κάνω ήταν να κάνουν πιο ακριβείς μετρήσεις. Michelson, ο οποίος έπαιξε σημαντικό ρόλο στην επανάσταση για να ακολουθήσει, με συμβούλευσαν να μην εισάγετε ένα “νεκρών” τομέα όπως η φυσική.

Ποιος θα το φανταζόταν ότι σε λιγότερο από μια δεκαετία στον 20ο αιώνα, θα ολοκληρωθεί αλλάξουμε τον τρόπο που σκεφτόμαστε του χώρου και του χρόνου? Ποιος στο σωστό μυαλό τους θα πω τώρα ότι θα αλλάξει και πάλι αντιλήψεις μας για το χώρο και το χρόνο? Κάνω. Στη συνέχεια, και πάλι, κανείς δεν με κατηγόρησε ποτέ ένα σωστό μυαλό!

Μια άλλη επανάσταση έλαβε χώρα κατά τη διάρκεια του περασμένου αιώνα — Κβαντομηχανική, που έκανε μακριά με την ιδέα μας της αιτιοκρατίας και ένα σοβαρό πλήγμα για το παράδειγμα του συστήματος-παρατηρητής της φυσικής. Παρόμοια επαναστάσεις θα συμβεί ξανά. Ας μην παραμείνουμε σε αντιλήψεις μας ως αμετάβλητο; δεν είναι. Ας μην σκεφτούμε παλιούς δασκάλους μας ως αλάθητο, για αυτές δεν είναι. Όπως Φάινμαν ίδιος θα ήθελε να επισημάνει, Φυσική μόνος του, κατέχει περισσότερα παραδείγματα του αλάνθαστο της παλιούς δασκάλους της. Και νιώθω ότι μια πλήρης επανάσταση στη σκέψη είναι ληξιπρόθεσμες τώρα.

Ίσως να αναρωτιέστε τι όλο αυτό έχει να κάνει με το σεξ. Καλά, Απλά σκέφτηκα ότι το σεξ θα πουλήσει καλύτερα. Είχα δίκιο, Δεν ήμουν? Εννοώ, είστε ακόμα εδώ!

Ο Feynman είπε, επίσης,,

Φωτογραφία "Caveman Chuck" Coker cc

Einstein on God and Dice

Although Einstein is best known for his theories of relativity, he was also the main driving force behind the advent of quantum mechanics (QM). His early work in photo-voltaic effect paved way for future developments in QM. And he won the Nobel prize, not for the theories of relativity, but for this early work.

It then should come as a surprise to us that Einstein didn’t quite believe in QM. He spent the latter part of his career trying to device thought experiments that would prove that QM is inconsistent with what he believed to be the laws of nature. Why is it that Einstein could not accept QM? We will never know for sure, and my guess is probably as good as anybody else’s.

Einstein’s trouble with QM is summarized in this famous quote.

It is indeed difficult to reconcile the notions (or at least some interpretations) of QM with a word view in which a God has control over everything. In QM, observations are probabilistic in nature. Δηλαδή, if we somehow manage to send two electrons (in the same state) down the same beam and observe them after a while, we may get two different observed properties.

We can interpret this imperfection in observation as our inability to set up identical initial states, or the lack of precision in our measurements. This interpretation gives rise to the so-called hidden variable theories — considered invalid for a variety of reasons. The interpretation currently popular is that uncertainty is an inherent property of nature — the so-called Copenhagen interpretation.

In the Copenhagen picture, particles have positions only when observed. At other times, they should be thought of as kind of spread out in space. In a double-slit interference experiment using electrons, για παράδειγμα, we should not ask whether a particular electron takes on slit or the other. As long as there is interference, it kind of takes both.

The troubling thing for Einstein in this interpretation would be that even God would not be able to make the electron take one slit or the other (without disturbing the interference pattern, that is). And if God cannot place one tiny electron where He wants, how is he going to control the whole universe?