Clocks

Nihanth Subramanya
Sep 14 · 7 min read
> a clock is really any device that periodically cycles through an immutable set of unique states.

> the cycle of day and night, which we now know to be a result of the earth's rotation about an axis passing through it, is hence a clock.

> we measure time using such clocks.

> it appears that we have an internal way within our minds by which we can tell if a sequence of events is periodic. For example, if I snap my fingers repeatedly such that the interval of time between each snap is approximately constant, one can intuitively observe this and conclude that my snapping is periodic.

> when making such a conclusion, the observer is comparing the snaps to an internal sequence of imagined snaps in their mind. It appears that our brain itself has some sort of internal clock to which it compares other temporally sensitive events.

> how can we be sure that this internal "biological clock" is actually perfectly periodic? There doesn't seem to be a way, to me, to prove this. It appears our perception of time is deeply ingrained within our minds. As a thought experiment, if the internal clock's frequency continuously increased according to some function, would we perceive a temporally warped reality? And even if it does, it appears that we are well adjusted to it, i.e. Our brains normalize reality to a constant time period.

> I wonder about the so called synchronization of the biological clock with other naturally occurring recurring events, such as the day/night cycle.

> it is idiomatic in English to talk about time flying or going slowly. (I omit other languages due to ignorance, but would be surprised if English was exclusive in this). My interpretation of this is that the periods of our biological clocks do vary, according to the perceived volume of events transpiring in our lives. But we as a society measure time based on the day/night cycle, so "time is flying" means that we perceive the day/night cycle to be shorter, which means that there are fewer cycles of the biological clock in the span of a solar day. I.e., the period of some level of the biological clock has increased relative to the period of the day/night cycle.

> I wasn't comfortable saying "the period of the biological clock" without "some level of" because it appears that we continuously re-synchronize by frequently checking the time. So if you asked someone to snap their fingers at one snap per second they'd probably be approximately accurate regardless of how eventful their life has been in the recent past.

> here, I want to draw attention to the theory of relativity. According to this theory, electromagnetic energy traverses equal intervals of space in equal intervals of time no matter the inertial state of the frame of reference. I.e. The speed of light is universally constant. I'll come back to this.

> It's widely agreed upon that anatomically, our brain is the center of perception, and perception appears to be linked inseparably to electrical activity within it. This to me suggests that light is closely linked to human perception of reality, since light is an electromagnetic wave.

> could the relativistic behavior of light be somehow linked to our intrinsic reliance on it to perceive reality? If the speed of light actually absolutely varied (contradictory to what the theory of suggests) it appears to me that we would be unable to observe the variance.

> this leaves me suddenly open to the possibility that relativity is merely a coincidence of our humanity, but I console myself by reminding myself that objective experiments designed to ascertain the relativistic behavior of light have been performed and to any practical margin of error have asserted the hypothesis.

> Now, I'd like to pick at the concept of relativity of light. I want to restate that according to the theory of relativity, light travels equal intervals of space in equal intervals of time. But if time isn't perceived absolutely, how can this be!? The solution is to re-examine our fundamental understanding of the concept of space. Is space uniform? Can space warp the same way that I suggested time might be warped, but is normalized in our brains? Could we be normalizing space as well? Continuing to accept the theory of relativity, it appears that an electromagnetic wave is sufficient to define time and space. Space is normalized to the wavelength, and time is normalized to the frequency.

> now, reconsider the basic thought experiment of an accelerating observer chasing a wave of light. I'd like to point out that classically, a frame of reference essentially describes the motion of an observer wrt the subject being observed. An inertial, or static frame of reference essentially refers to an observer moving at a constant velocity wrt the subject, i.e. The distance between observer and subject in space changes at a constant rate in a constant direction. An accelerating or non-inertial FOR refers to an observer whose distance from the subject changes at either a rate that is not constant, in a direction that is not constant or both. Here's the catch, according to relativity: it's impossible to be in a non-inertial frame of reference when the subject is light, because the velocity of light is constant wrt all frames of reference - which are otherwise inertial or non-inertial. As a thought experiment, imagine a fixed observer observing and an observer in uniform circular motion, both observing a wave/particle of light. According to relativity, the velocity of light must appear simultaneously constant both to the fixed observer and to the rotating observer, even though the observers are changing their direction of relative motion. How can this be?! The answer is in the warping of space. It appears that in this system the path of light curves to accommodate the changing relative direction of motion of the observers, such that both the observers perceive the light to be moving at constant velocity. This is impossible in a three dimensional coordinate system. But remember, space is also defined by light! That means space itself is "curved" or "warped" in this system. This is my interpretation of the so called poly-dimensionality of spacetime. In reality as we perceive it, light would appear to be traveling at a constant velocity even to the physicist observing this system (I.e., us) so we would be unable to detect the curvature of light through space (I.e the warping of space) simply by observing the light.

This means that every observer causes light to curve a bit in order to accommodate it. This means that every observer causes spacetime to warp.

Do you see where this is going? In the universe we observe, there exist an unimaginably large number of bodies scatters through space. There is no absolute observer, they're all moving wrt each other, and space curves to accommodate all of them, where "curves to accommodate" means, "changes such that light moving through it appears to move at constant velocity to every single body".

Now, every object in the universe is actually made up of tiny particles (we call this atomic structure). You probably know that we have been able to identify certain fundamental particles. These particles appear to each warp space on their own, i.e they are constantly changing their configuration non-inertially wrt each other. We call this property of intrinsic capacity to warp spacetime "mass", and since they are non-inertial to each other we hypothesize a fundamental characteristic "spin" that is linked to the "direction" in which they warp spacetime relative to each other. This is analogous to the clockwise or counter-clockwise rotation of the uniformly circularly moving observer in the original system we were observing. However, clockwise/counterclockwise is characteristic to two dimensional motion, and "spin" is something more general - simply a way to describe the fact that these particles appear to warp space differently.

All matter is made up of fundamental particles, and so all matter curves space according to the sum total of the masses of the constituent particles.

Now the question arises - what on earth is gravity? How does it work? Somehow, everything appears to be linked - relativity, warping of spacetime, gravity. But how? All other forces of nature appear to be linked to the existence of corresponding fundamental particles. Is there a "gravity particle", a graviton?

If so, it too should have mass and spin and therefore warp spacetime, should it not? How would it all fit?

If not, then why are objects that have mass attracted to each other? Why does the amount of space between them tend to decrease as time (which, as we have discussed, is a not-so-straightforward concept in itself) progresses?

Light doesn't seem to move at constant velocity wrt itself, therefore particles of light have no effect on the curvature of spacetime. I.e. photons have no "rest mass"

To be continued.
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