# 轻旅行时间效应和宇宙学特点

This unpublished article is a sequel to my earlier paper (also posted here as “为无线电源和伽玛射线暴管腔围油栏?“). This blog version contains the abstract, introduction and conclusions. The full version of the article is available as a PDF file.

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Abstract

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.

#### Introduction

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, 例如, is already eight minutes old by the time we see it. This delay is trivial; 如果我们想知道现在是怎么回事太阳, 所有我们需要做的就是等待八分钟. We, nonetheless, have to “正确” for this distortion in our perception due to the finite speed of light before we can trust what we see.

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. 换句话说, we do not attribute the manifestations of the finite speed of light to the properties of the underlying reality. 相反，, we work out our perceived picture that this model predicts and verify whether the properties we do observe can originate from this perceptual constraint.

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’s famous statement, “错觉是光的真理。”

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 “luminal” 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, 然而，, extended beyond GRBs to symmetric radio sources, which can also be regarded as perceptual effects of hypothetical luminal booms.

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.

#### Similarities between Light Travel Time Effects and SR

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: “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.” 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. 例如, if a system $K$ is moving with respect to another system $k$ along the positive X axis of $k$, then an object at rest in $K$ at a positive $x$ is receding while another object at a negative $x$ is approaching an observer at the origin of $k$.

The coordinate transformation in Einstein’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. 然而, in the current interpretation of SR, the coordinate transformation is considered a basic property of space and time.

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.

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. 特别是, 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.

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’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, 例如.

#### Conclusions

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.

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’s equations. It may be possible to disentangle the covariance of electrodynamics from the coordinate transformation, although it is not attempted in this article.

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. 此外, the perception of superluminality is modulated by LTT effects, and explains $gamma$ 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.

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, 然而，, results in multiple solutions. 因此，, 绝对, physical reality is beyond our grasp, and any assumed properties of the absolute reality can only be validated through how well the resultant perceived 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.

The coordinate transformation in SR can be viewed as a redefinition of space and time (或, more generally, 现实) 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 “实” 空间和时间, 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.

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. 然而, this option is yet another philosophical stance against the unknowable absolute reality.

# 虚幻宇宙 — Seeing Light in Science and Spirituality

The same delay in seeing has a lesser known manifestation in the way we perceive moving objects. It distorts our perception such that something coming towards us would look as though it is coming in faster. Strange as it may sound, this effect has been observed in astrophysical studies. Some of the heavenly bodies do look as though they are moving several times the speed of light, while their “实” speed is probably a lot lower.

#### Light in Physics

Einstein chose the first route. In his groundbreaking paper over a hundred years ago, he introduced the special theory of relativity, in which he attributed the manifestations of the finite speed of light to the fundamental properties of space and time. One core idea in special relativity (SR) is that the notion of simultaneity needs to be redefined because it takes some time for light from an event at a distant place to reach us, and we become aware of the event. The concept of “现在” doesn’t make much sense, as we saw, when we speak of an event happening in the sun, 例如. 同时性是相对的.

Einstein defined simultaneity using the instants in time we detect the event. 检测, 他将其定义, involves a round-trip travel of light similar to Radar detection. We send out light, and look at the reflection. If the reflected light from two events reaches us at the same instant, they are simultaneous.
Another way of defining simultaneity is using sensing — we can call two events simultaneous if the light from them reaches us at the same instant. 换句话说, we can use the light generated by the objects under observation rather than sending light to them and looking at the reflection.

The other possibility has an advantage when it comes to describing objects in motion because it corresponds better with how we measure them. We don’t use Radar to see the stars in motion; 我们仅仅感测的光 (或其他辐射) 他们来了. But this choice of using a sensory paradigm, rather than Radar-like detection, to describe the universe results in a slightly uglier mathematical picture.

For symmetric objects, if we assume (因为我们经常做的) 该波开始的旅程大致在同一时刻, we end up with a picture of two “实” 对称的叶片或多或少的方式看到它们.

But there is different possibility that the waves originated from the same object (这是在运动) 在两个时间不同的时刻, 在同一时刻到达望远镜. This possibility explains some spectral and temporal properties of such symmetric radio sources, which is what I mathematically described in a recent physics article. 现在, which of these two pictures should we take as real? 两个对称的物体，因为我们看到他们或一个物体以这样的方式移动，就好像给我们的印象? Does it really matter which one is “实”? Does “实” 意味着在这方面的任何?

The philosophical stance in implied in special relativity answers this question unequivocally. There is an unambiguous physical reality from which we get the two symmetric radio sources, although it takes a bit of mathematical work to get to it. 数学排除了移动以这样的方式单一对象的可能性，以模拟的两个对象. 从本质, 我们看到的是什么就在那里.

The ramifications of the two different philosophical stances described above are tremendous. Since modern physics seems to embrace a non-phenomenalistic view of space and time, 它发现自己不符合哲学的一个分支，. 哲学和物理学之间的鸿沟已经发展到这种程度，诺贝尔得奖物理学家, 史蒂芬温伯格, 想知道 (在他的书 “终极理论之梦”) 为什么从哲学到物理学的贡献一直这么小得惊人. 这也提示哲学家做出类似声明, “无论是“本体的现实导致惊人的现实’ 还是“本体的现实是独立于我们的感知它’ 还是“我们感觉到现实的本体,’ 问题仍然是本体现实的概念，是一个完全冗余的概念，科学的分析。”

We have to come to terms with the fact that when it comes to seeing the universe, 有没有这样的事，作为一个错觉, 这也许正是歌德指出，当他说, “错觉是光的真理。”

In my view, the two options are not inherently distinct. The philosophical stance of SR can be thought of as coming from a deep understanding that space is merely a phenomenal construct. If the sense modality introduces distortions in the phenomenal picture, we may argue that one sensible way of handling it is to redefine the properties of the phenomenal reality.

#### Role of Light in Our Reality

This philosophical grand-standing may sound presumptuous and the veiled self-admonition of physicists understandably unwelcome; but I am holding a trump card. Based on this philosophical stance, I have come up with a radically new model for two astrophysical phenomena, and published it in an article titled, “为无线电源和伽玛射线暴管腔围油栏?” in the well-known International Journal of Modern Physics D in June 2007. This article, which soon became one of the top accessed articles of the journal by Jan 2008, is a direct application of the view that the finite speed of light distorts the way we perceive motion. Because of these distortions, the way we see things is a far cry from the way they are.

We may be tempted to think that we can escape such perceptual constraints by using technological extensions to our senses such as radio telescopes, electron microscopes or spectroscopic speed measurements. 毕竟, these instruments do not have “感悟” per se and should be immune to the human weaknesses we suffer from. But these soulless instruments also measure our universe using information carriers limited to the speed of light. We, 因此, cannot escape the basic constraints of our perception even when we use modern instruments. 换句话说, the Hubble telescope may see a billion light years farther than our naked eyes, but what it sees is still a billion years older than what our eyes see.

Our reality, whether technologically enhanced or built upon direct sensory inputs, is the end result of our perceptual process. To the extent that our long range perception is based on light (and is therefore limited to its speed), we get only a distorted picture of the universe.

#### Light in Philosophy and Spirituality

Once we appreciate the special place accorded to light in modern science, we have to ask ourselves how different our universe would have been in the absence of light. 当然, light is only a label we attach to a sensory experience. 因此，, to be more accurate, we have to ask a different question: if we did not have any senses that responded to what we call light, would that affect the form of the universe?

The immediate answer from any normal (就是说, non-philosophical) person is that it is obvious. If everybody is blind, everybody is blind. But the existence of the universe is independent of whether we can see it or not. Is it though? What does it mean to say the universe exists if we cannot sense it? Ah… the age-old conundrum of the falling tree in a deserted forest. Remember, the universe is a cognitive construct or a mental representation of the light input to our eyes. It is not “out there,” but in the neurons of our brain, as everything else is. In the absence of light in our eyes, there is no input to be represented, ergo no universe.

If we had sensed the universe using modalities that operated at other speeds (echolocation, 例如), it is those speeds that would have figured in the fundamental properties of space and time. This is the inescapable conclusion from phenomenalism.

The parallels between the noumenal-phenomenal distinction in phenomenalism and the Brahman-Maya distinction in Advaita are hard to ignore. This time-tested wisdom on the nature of reality from the repertoire of spirituality is now reinvented in modern neuroscience, 它把现实，由大脑产生一种认知表征. 大脑使用感觉输入, 内存, 意识, 甚至语言成分在炮制我们的​​现实感. 这种观点的现实, 然而，, 是物理的东西是没有来的条款. 但是在某种程度上，它的舞台 (空间和时间) 是现实的一部分, 物理学是不能幸免的哲学.

Recognizing and making use of the interconnections among the different domains of human endeavour may be the catalyst for the next breakthrough in our collective wisdom that we have been waiting for.

# Sony World Band Radio

I recently bought a Sony World Band Radio receiver. It is a beautiful machine with some twenty frequency bands and all kinds of locks and tricks to latch on to distant radio stations. I bought it for my father, who is fond of listening to his radio late into the night.

Two days after I bought the radio, my father suffered a severe heart failure. A congestive heart failure (CHF) is not to be confused with a heart attack. The symptoms of a CHF are deceptively similar to an asthma attack, which can be doubly treacherous if the patient already has respiratory troubles because the early care may get directed to the lungs while the troubled heart may be ignored. So I thought I would discuss the symptoms here in the hope that it will help those with aging family members who may otherwise misidentify a potential CHF. Much more information is available on the Internet; try Googling “congestive heart failure.”

For asthma patients, a danger sign of a heart failure is persistent breathing difficulty despite inhalation medication. Watch out for breathing trouble that increases when they lie down, and subsides when they sit up. They may have consequent sleeplessness. If they show the symptoms of water retention (swelling in lower limps or neck, unexpected sudden weight gain etc.), and if they have other risk factors (hypertension, irregular heart beat), please do not wait, rush to the hospital.

The prognosis for CHF is not good. It is a chronic condition, progressive and terminal. 换句话说, it is not something we catch like the flu and get better soon. Depending on the stage the patient is, we have to worry about the quality of life, palliative care or even end of life care. Once a heart has started failing, it is difficult to reverse the progression of the onslaught. There are no easy solutions, no silver bullets. What we can concentrate on, 真, is the quality of their life. And the grace and dignity with which they leave it. For most of them, it is their last act. Let’s make it a good one.

By my father’s bedside now, listening to the Sony, with all these sad thoughts in my head, I remember my first taste of real winter in the fall of 1987 in Syracuse. I was listening to the weatherman of the local radio station (was it WSYR?). While lamenting the temperatures going south, he observed, rather philosophically, “C’mon, we all know there’s only one way the temperatures can go.” 是的, we know that there is only one way things can go from here. But we still mourn the passing of a summer full of sunshine and blue skies.

The Sony radio plays on, impervious to these doleful musings, with young happy voices dishing out songs and jokes for the benefit of a new generation of yuppie commuters full of gusto and eagerness to conquer a world. Little do they know — it was all conquered many times over during the summers of yester years with the same gusto and passion. The old vanguards step aside willingly and make room for the children of new summers.

The new generation has different tastes. They hum to different iTunes on their iPods. This beautiful radio receiver, with most of it seventeen odd short wave bands now silent, is probably the last of its kind. The music and jokes of the next generation have changed. Their hair-do and styles have changed. But the new campaigners charge in with the same dreams of glory as the ones before them. Theirs is the same gusto. Same passion.

Perhaps nothing and nobody really passes on. We all leave behind a little bit of ourselves, tiny echoes of our conquests, memories in those dear to us, and miniscule additions to the mythos that will live on. Like teardrops in the rain.