Einstein theory

Introduction of Einstein Theory 

An enduring mystery in modern physics has been the reason for the existence of the famous theory of relativity. The story goes that the great physicist, Werner Heisenberg, on his deathbed, stated that he wanted to ask God two things—why relativity and why turbulence? While the problem of turbulence belongs to another field of physics (and beyond our scope here), this paper aims to address Heisenberg’s first question—why relativity?

That relativity should be one of the puzzling phenomena foremost in Heisenberg’s mind is hardly surprising. The brain-child of Einstein, relativity invokes extremely bizarre concepts—time slowing down, space contracting, curvatures in space-time, and so on. While the mathematical formulation of relativity has, over the last century, been found to be consistent and sound, the question nonetheless remains: Why do these contortions of time and space occur?

Often physicists get around the lack of intuitive understanding by claiming that “we understand if we can compute,” thus brushing aside the fact that we may not actually know why the mathematics employed in a particular situation work. In other words, we often employ a mathematical camouflage for our ignorance.

This paper addresses this problem by providing an intuitive understanding of special relativity and explains why these distortions of time and space occur—an explanation that Einstein himself had not realized. This explanation also reveals something of critical importance in the very nature of science itself.

The Michelson-Morley Experiment

Our story begins in 1887, the year of the famous Michelson-Morley experiment. This experiment was a defining moment in the history of physics because it was the first crack in the wall of this grand monument called classical physics.

Prior to that fateful event, the classical physics of Newton and Maxwell appeared to be reaching a state of total fulfilment. Everything had fallen into place and this grand edifice of classical physics appeared almost complete, with only some subtle final touches needed to round off an apparently perfect structure.

Ironically, it was Albert Michelson who casually remarked, at that time, that all that remained undone in physics was to fill in the sixth decimal place (meaning to say that physicists only had to fine-tune the established classical laws). Yet, in 1887, together with Edward Morley, Michelson himself lit the fuse for a scientific explosion that shattered a very fundamental premise of classical physics. Their experiment ushered in the era of what came to be called modern physics, a new scientific understanding whose theoretical framework rests entirely upon the wonderfully strange world of relativity and quantum theory.

The Michelson-Morley experiment helped destroy the classical idea of an absolute space and time, and it did this by first undermining the concept of the ether. The ether was the hypothetical medium considered necessary for light to travel in. It was thought, at that time, that every wave required a medium, and light was an electromagnetic wave. So, just as ocean waves required water, and sound waves required air, it was felt that light waves required the ether as the medium to travel in.

What the ether actually was, however, proved to be a puzzle since it appeared to be totally undetectable. It had zero density, perfect transparency, and no measurable properties whatsoever. Little wonder then that it had been impossible to determine exactly how the ether travelled in relation to the Earth.

Nonetheless, what Michelson and Morley set out to do, in 1887, was to measure the effect of the Earth moving in relation to this hypothetical ether. The scientific reasoning at that time was as follows:

Since the Earth rotates around the Sun, and if—as was widely thought—the ether was stationary relative to the Sun, the Earth would then be flying through the ether at its orbital speed of about 30 km per second. We, on the Earth, would thus find this “ether wind” moving past us at this same speed (the same way we would feel the air whizzing past us in an open car).

Also, it was noted that, in orbiting the Sun, the Earth travels in opposite directions every six months. So, even if the ether was not stationary relative to the Sun, it cannot remain stationary to the Earth throughout the year. We should generally be feeling the ether wind traveling past us.

The Michelson-Morley experiment was designed to measure the effect of this ether wind, and the key instrument employed was the Michelson interferometer. This ingenious device splits a light ray into two parts and sends them traveling to-and-fro along different directions perpendicular to each other. The two light rays meet again at the end of their different paths and interact with each other to form an interference pattern. The difference in the time required by the two light rays to complete their respective journeys affects this interference pattern.

If one light ray travels along the line of motion of the ether wind and the other perpendicular to the motion of this same ether wind, the two light rays should require different times to complete the journey. In effect, it is like comparing the different times taken for an athlete to run to and fro along a track when there are different wind directions. In one scenario, the wind is first blowing directly against him and then directly behind him (when he turns around). In the other scenario, the wind is first blowing at him from his left and then from his right (when he turns around). Because the wind’s direction affects the runner’s speed, it can be shown that the runner would require more time to complete the journey under the conditions of the first scenario.

In the interferometer, the different times required by the two light rays (for their respective journeys) affect the interference pattern they form when they meet at the end. Now, if we rotate the interferometer so that the direction of the ether wind relative to the paths of the two light rays are changed, we would expect this time difference to be altered. This, in turn, should then cause a change in the interference pattern.

To the surprise of the scientific community, however, Michelson discovered no change in the interference pattern no matter how he rotated the interferometer. The ether wind appeared not to be there at all!

Because this result was so surprising, similar experiments were repeated many times (by Michelson and others) under different conditions. Michelson and Morley even conducted the experiment on a mountaintop in case that somehow made a difference. In the end, however, it was found that the varying conditions made no difference whatsoever. All these other experiments consistently produced a null result, i.e. no change in the interference pattern. So where was the ether wind?

Explaining the Michelson-Morley Experiment

The null result of the Michelson-Morley experiment baffled the physics community. Why was the ether wind undetectable? A number of attempts were made to explain this unexpected finding.

One proposed explanation that received serious attention was the “ether drag” hypothesis, which suggested that the Earth dragged the ether along with it when it moved. This explanation, however, was found to be invalid because it contradicted the findings of other experiments. Notably, the “stellar aberration” observed by British astronomer James Bradley in 1728 demonstrated that there really was no ether drag.

What Bradley observed was that the position of the stars appears to rotate in a circular motion over the period of a year. This meant that the direction of the light rays from the stars were affected by the motion of the Earth around the Sun. Just as raindrops appear slanted towards us when we run forward, the light rays from stars appear slanted because of the motion of the Earth. If the Earth dragged along the ether, this stellar aberration would not occur.

So the question remained. If the Earth did not drag along the ether, why was the ether wind not detected by the Michelson-Morley experiment? H. A. Lorentz and G. F. FitzGerald, working independently of each other, came up with another possible explanation. They suggested that the length of objects contracted in the direction of the ether wind and remain unchanged in the other directions perpendicular to this wind, an effect now known as the Lorentz-FitzGerald contraction.

This would mean that the two perpendicular arms of the Michelson interferometer (along which the light rays travelled) would have different lengths depending on how the interferometer was orientated in relation to the ether wind. Their lengths would vary in just such a way that compensated for the effect of the ether wind on the light rays, the end result being that both light rays would take the same amount of time to traverse the different paths. Hence the null result of the Michelson-Morley experiment.

Technically, the Lorentz-FitzGerald contraction did provide a solution to the Michelson-Morley experiment. The problem with the theory, however, was that it missed the big picture. While it explained why the ether wind could not be detected, the theory nonetheless accepted the presence of an ether wind.

It was finally left to a young patent clerk, in 1905, to make the bold suggestion that the Michelson-Morley experiment was actually a vital clue to the very nature of time and space itself. The visionary difference here was the realization that there was no ether at all!

Einstein’s Postulates

In 1905, while working as a patent clerk, the 26-year-old Albert Einstein published three scientific papers in one issue of the Annalen der Physik. This issue of the physics journal has since become a unique collector’s item because any one of those three papers, alone, would have won Einstein the Nobel Prize in physics.

Ironically, of the three papers, Einstein was awarded the Nobel Prize in 1921 for his paper on the photoelectric effect, and not for the one on the theory of relativity, the theory synonymous with his name. Relativity—Einstein’s main work—was apparently still being disputed in 1921. This was hardly surprising given the bizarre nature of relativity. Effects like time dilation, length contraction, and distortions in space-time, were not exactly your everyday intuitive events. How then did Einstein reason his way to such apparently fantastical scientific conclusions?

In his 1905 paper “On the Electrodynamics of Moving Bodies”, Einstein introduces the two postulates that form the starting point for his theory of relativity. The first of these postulates, which Einstein calls the “Principle of Relativity” gives his whole theory its name.

The Principle of Relativity abolishes the idea of an absolute state of rest. All observers moving at constant velocity relative to each other thus have equal status; no observer can claim to be the “special one” at rest. For example, a man standing on a train station may claim that he is stationary while his friend on the train is moving. His friend, however, may claim, instead, that he is the one actually at rest while the man on the platform is moving. Both are equally correct. According to Einstein, all velocities are relative. Hence, an object’s designated velocity conveys little meaning unless we also know which frame of reference we are viewing this velocity from.

While this first postulate may be revolutionary, it is nonetheless reasonably intuitive, i.e. it feels logical in a “common sense” way. Einstein’s next postulate, however, is extremely counter-intuitive, and weird consequences arise from it. Unlike the first postulate, this one defies common sense. The second postulate states that the speed of light is constant relative to all frames of reference.

Why this is so weird? If we observe a flash of light while standing on Earth, we will find it travelling from us at 300,000 km per second. Another observer, travelling in the same direction as this light ray, should then measure its speed, relative to himself, to be slower. He is, after all, chasing after it. Einstein’s second postulate, however, states that this simply does not happen.

Let us look at an analogous situation. If we are in a police car chasing after a getaway car, we would expect the getaway car to move away from us at a slower speed (relative to us). If the police car manages to move at the same speed as the getaway car, the getaway car would not even be moving away from us at all. Its velocity relative to us would then be zero, since we are keeping up with it. This would be common sense.

Now imagine the scenario if the getaway car behaves like Einstein’s light ray. What happens then is this. The getaway car continues to pull away from the police car at the same speed, no matter how fast the police car chases after it. It’s the ideal getaway car. It runs away from us at exactly the same speed no matter how we race after it.

The really strange thing is this. A man standing on the pavement also sees this same getaway car pulling away from him at the same speed as we do in the police car. In other words, the speed of the getaway car relative to the man on the pavement, and relative to us in the police car chasing after it, is exactly the same! For example, if the getaway car is pulling away from the man on the pavement at 100 km per hour, it is also pulling away from us in the police car at 100 km per hour, even though we are tearing after it as fast as we can. How can this be? Surely this defies common sense.

This weird behaviour of the getaway car is, nonetheless, what Einstein is proposing for the light ray. The same light ray travels away from all observers at the same speed of 300,000 km per second, regardless of whether the observer is stationary or moving. The velocity of the observer makes no difference whatsoever. The speed of light is constant relative to all frames of reference. This then is Einstein’s second postulate. It sounds positively crazy!

Nonetheless, this second postulate of relativity has passed the test of time. It has survived a whole century of close scientific scrutiny, and has become a fundamental cornerstone of all modern physics. How do we explain this phenomenon?

Actually, Einstein never gave an explanation for his second postulate. That, in fact, is why it is called a postulate. A postulate is a principle simply assumed to be true, and then used as the basis for further derivations and conclusions. For some reason, Einstein’s second postulate works. But why does it work? And why is nature so strange? That was the question Heisenberg, on his deathbed, was purportedly still puzzling over. Why—Heisenberg was essentially asking—does relativity exist at all?

Distortions in Time and Space

How is it possible for the speed of light to remain constant to all frames of reference? Surely, observers moving at different velocities should see the same light ray travelling at different speeds relative to themselves. How is it that this does not happen?

There is one possible solution to this conundrum. Perhaps time and space actually distort when we travel, and they distort in just such a way that all observers still measure the speed of light as the same. Strange as it may sound, this was exactly the solution Einstein implemented in his theory of relativity, and incredibly, it worked!

We can almost sense the knowing smile appearing on the lips of all lovers of conspiracy theories. Here, surely, must be the ultimate conspiracy theory! Even time and space conspire to contort themselves in exactly the correct way needed to fool us into measuring the speed of light as constant.

These contortions in time and space are no mean feat either. They are extremely complicated, and require time to slow down, space to contract, and simultaneity to become an observer-dependent phenomenon.

This last distortion on simultaneity means that while one observer may consider two events to be occurring at the same time, another observer may not. Simultaneity is relative. This means, also, that while one observer may perceive Event A to occur before Event B, another observer may, instead, perceive Event B to occur before Event A. The temporal sequence of events may be different for different observers.

While all these distortions in space-time appear extremely complicated, there is nonetheless a method in their madness. All the distortions appear precisely engineered so that we always end up measuring the speed of light as constant. We can never measure the speed of light in vacuum as anything other than 300,000 km per second, no matter how fast, or in which direction, we move. Time and space consistently modify themselves so that we never measure the speed of light as anything else. It is really like an elaborate conspiracy.

Yet, why would nature behave this way? Could we be missing something? If we step back and reexamine the situation without preconceived bias, one thing does seem evident. If the speed of light is always constant, while time and space so readily transform, is it not more logical to consider the speed of light—rather than time and space—as the fundamental entity?

Perhaps, by considering time and space to be fundamental, we have been placing the cart before the horse all this while. The reverse, in fact, may be true. Perhaps time and space are actually entities derived from the more fundamental phenomenon, which is the speed of light. A closer examination will reveal that this is actually the case, a realization that will also highlight a crucial quality we need to recognize about the very nature of science itself.

The Physiological Basis of Relativity

Einstein and the physicists of his day never grasped why relativity occurs. Their poor understanding of human physiology probably accounted for that. Apart from their lack of training in that area, the very science of physiology itself was insufficiently advanced in the early twentieth century.

This reason for Einstein’s failure to explain why relativity occurs may come as a surprise. What has physiology to do with relativity? Startling as it may sound, human physiology has everything to do with relativity. The theory of relativity would not even exist if not for the way our human body functions!

How do we come to such a staggering conclusion? First, we need to raise the question that has, for centuries, been left unaddressed. Actually, the question has never even been asked, let alone addressed. This question, nonetheless, has been lurking in the shadow of this long and grand exhibition of human scientific achievements ever since its misty beginnings centuries ago.

The question is simply this: Are our scientific theories actual theories of phenomena that are independent of man, or are they merely theories of how man experiences the universe? In other words, is our science a study of the universe that is independent of us, i.e., one that would be equally valid even if we were not around? Or—as we are now asking—are our scientific theories actually only theories of how our mind and senses perceive and interpret the universe?

While scientific theories are based on data obtained from scientific experiments, the key point is this: We need to observe these experiments. Even the use of scientific measuring apparatus does not obviate this requirement; ultimately we have to retrieve the data from the scientific equipment, and this means observation by humans. This is the crucial point. Sooner or later, our human sensory apparatus and our consciousness come into play. It is unavoidable.

To the extent that they need to be observed, all scientific data are thus observer dependent. The real question, however, is this: Is the actual content of the data we observe also affected by this observer dependence? In other words, does this need to be observed show up in the very data itself? There is, naturally, an inherent problem with answering this question. We simply cannot compare observed data with unobserved data. No observation means no data; so we do not have any “unobserved data” to compare with. How then do we address this question?

All we can do, really, is to look for clues suggesting this observer dependence in the observed scientific data itself. So, are there these clues that indicate our observed data is intrinsically tied in to our physiological sensory apparatus and/or to our consciousness (i.e. the things that enable us to be observers)? The answer that leaps back at us is glaringly clear: it is, in fact, a resounding “Yes”!

The very foundation of all modern physics—both relativity and quantum theory—point to the fact that our scientific data are actually observer dependent. Without the observer, much of quantum physics and relativity would not even make sense. This strongly suggests that our scientific theories are actually theories of how we experience the universe, as opposed to being theories of a universe that is independent of us as observers.

Let us return our focus now back onto the theory of relativity. Relativity essentially deals with time and space, so the crucial question here is this: Are time and space inherent properties of the universe (independent of man) or are they only entities that reflect our human experience?

According to the theory of relativity, time and space vary according to the frame of reference of the observer. These entities, therefore, vary depending on the observer’s experience. If they are entities independent of man, why should our vantage point matter?

This strongly suggests that what we define as time and space are, in fact, not inherent properties of the universe. They are simply our time and space, i.e., what is experienced by us. Thus, time and space, as defined by our science, are actually only properties pertaining to how our senses interpret the universe.

There is a further critical clue from the theory of relativity. And that is Einstein’s second postulate: the speed of light is constant to all frames of reference. The idea that time and space invariably modify themselves just so that we always measure the speed of light as constant almost suggests a conspiracy by nature. Actually, there is no such conspiracy. The speed of light happens to be constant to all human observers simply because the speed of light (which is the speed of electromagnetic transmission) plays an intrinsic role in how our body and our perceptual apparatus function. The speed of electromagnetic transmission directly affects how we experience the universe because electromagnetism plays a crucial role in the functioning of our biological sensory apparatus.

The transmission of light is essentially the transmission of a disturbance in the electric and magnetic fields. This disturbance is not immediately felt by another charged particle at a distance. This is akin to how a sudden shaking at one end of a long rope is not felt immediately at the other end of the rope. First, the disturbance has to be conveyed along the rope to the other end. Likewise, a disturbance in the electric and magnetic fields needs to be transmitted first in order to be felt at a distance, and the rate of this transmission is exactly the speed of light, since light is an electromagnetic wave.

A similar transmission of electrical disturbance has to occur in the functioning of the human body. For example, an electrical signal in a nerve cell has to be transmitted along the axon of the nerve cell before it can be felt by another nerve cell at the other end. The rate of this transmission is dependent on the general rate of transmission of any electrical disturbance, which is the speed of light.

Herein lies the physiological basis of relativity. And herein lies the concrete evidence that our science is actually a science of how we experience the universe, and not a science of a universe independent of us as observers. Let us look more closely at this critical clue provided by Einstein’s second postulate.

Why the Speed of Light is Constant

The physiological basis of relativity stems from the fact that all our biological mechanisms function via electromagnetic interactions. Every single organ—as well as every single cell—in our body functions via electromagnetism.

Muscular force is actually electromagnetic force. We are able to move only because our muscular contractions are mediated by electromagnetism. We literally move and breathe via electromagnetic interactions. All our sensory apparatus also rely on electromagnetic interactions. Even our nerves transmit information via electromagnetism; hence our brain functions via electromagnetism. This is the crucial point. It all means that our sensory experience of the universe is mediated by electromagnetism.

Since the speed of light is the speed of electromagnetic transmission, the reason for its constancy now becomes evident. It is constant because of a limitation in our perceptual ability. We are simply unable to experience the speed of light varying because both our perceptual apparatus and our brain function via electromagnetic transmission. In other words, we cannot experience the speed of light to be anything other than constant because the very rate at which we ourselves function depends on the speed of light!

We are essentially trapped inside the system, like the characters inside a video movie. If someone slows down the video, all the characters inside the video—as well as everything else there—slows down equally. The characters’ movements, and even their rate of thinking, slow down exactly in line with everything else. How then would these characters inside the video notice any difference in the speed of the video itself? They would, in fact, not notice any change at all, simply because they cannot escape the system to view it from the outside.

As another example, suppose we want to measure the expansion of an iron rod being heated inside an oven. If we use an iron ruler inside the oven to make the measurement, we detect no expansion. This is because the iron ruler expands by the same proportion as the rod. This iron ruler is incapable of detecting a change because it is also inside the system and equally affected by it.

Likewise, we cannot measure any change in the speed of light because we are also “trapped inside the system.” If the speed of electromagnetic transmission slows down, we ourselves—our actions and our thoughts—slow down by the same amount, so we cannot detect any change. That is the reason for Einstein’s second postulate.

Let us now look at a more elaborate analogy that even more closely parallels the case regarding the speed of light. Suppose we wish to measure the speed of a river flow, and we follow this procedure: We place a buoy on the river as a marker and determine the distance the buoy travels. We then divide this distance by the elapsed time to obtain the speed.

Suppose, unconventionally, we now decide to measure time by the number of turns of a waterwheel placed on the same river, i.e., we define one unit of time by one turn of the waterwheel. If the rate at which the buoy travels and the rate at which the waterwheel turns are both proportional to the rate of the river flow, we will now always measure the speed of the river flow as constant. The reason for this is that the waterwheel turns correspondingly faster whenever the river flows faster, so we cannot detect the change if we keep to our unconventional way of defining time.

The curious point in this analogy is, of course, our unconventional way of measuring time with the waterwheel, a procedure that makes our measured time dependent on the river flow itself. What we need to check, then, is whether or not we are doing something similar in our actual determination of time. So what determines our human experience of time?

Since the rate of all our bodily functions, including our rate of thinking, depend on the rate of electromagnetic transmission, it can be seen that we have arbitrarily defined time as the rate of electromagnetic transmission in our perceived space. This means that we have been trying to determine the speed of light—a form of electromagnetic transmission—by using a measure of time that also depends on the speed of light! We are thus in a similar situation to that in the river flow analogy. Little wonder, then, that we always measure the speed of light as constant.

But do all our clocks actually measure time this way? Electrical clocks and mechanical clocks not utilizing gravity clearly employ the rate of electromagnetic phenomena to measure time. But are there not other types of time-measuring devices, ones that make use of other phenomena—for example, the rate of radioactive decay, the rate at which the Earth moves around the Sun, and so on? These other time-measuring methods do indeed exist, but that actually does not alter the underlying logic why the speed of light is constant.

To see this, let us return to our analogy: Suppose, now, we want to check whether we can use an anemometer—an instrument that rotates depending on wind flow—instead of the waterwheel, to measure time. If we find that the anemometer rates do not agree with that of the waterwheel, we will have to conclude that we actually cannot use the anemometer instead. This is because we have already defined our time as the rate of water flow. Only if, for some reason, the rate of wind flow happens to be proportional to the water flow in this part of the world, can we utilize the anemometer as a time-measuring instrument.

That is the key point. Our definition of time remains unchanged even if we employ other methods to measure it. These other methods of measuring time will simply have to conform to the definition of time that we already have. Hence, if we have already defined our time according to how we experience it, this time will be proportional to the rate of electromagnetic transmission.

It does not matter, then, what type of clock we use to measure the time we have already defined in this way. We may use other phenomena—like the rate of radioactive decay—to measure time only because we have already determined that they run at proportional rates to electromagnetic phenomena. Obviously, then, it will make no difference to our measurement of the speed of light. By our definition of time according to how we experience it, we have, in fact, also arbitrarily defined the speed of light to be constant.

In this sense, then, the speed of light is the more fundamental entity compared to our time and space. Effectively, we have defined our time and space based on the speed of light because our sensory apparatus functions via electromagnetic transmission. That explains why the speed of light is always constant, while time and space vary depending on the vantage point of the observer. By considering time and space to be fundamental entities—while regarding the speed of light as secondary—we had truly been placing the cart before the horse all this while!

Furthermore, since the speed of light is the more fundamental entity only because our sensory apparatus rely on electromagnetism, it would be hard to escape the conclusion that the very foundation of our science is actually our physiological experience, and not any phenomenon that is independent of us as conscious observers. The theory of relativity demonstrates that even time and space are only secondary entities derived from our conscious experience.

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