SeekingToUnderstand

In the nomenclature of physics, is there a formal name for "light pressure" or "photon density"? losfomot, I don't know what you are referring to? Also is there a word for a vacuum that is not just that absence of atoms, but also the absence of photons? And does the technology exist to create such a vacuum? swansont, What are the names of the phenomena that use this effect?

Given that photons have a momentum, is there an analogy to atmospheric pressure that can be made - but in this case for light instead of for atmospheric atoms? If so, how strong or weak compared to atmospheric pressure would this "light pressure" be?

On a website regarding the physics of solar sailing, I read that "At Earth's distance from the sun, the solar flux, Ss, in space is about 1.4 kilowatts per square meter. This is enough power to run a hair dryer continuously, but not enough to power a car." I would like to know on the surface of the earth what an average range for the number of photons per cubic meter is? I know this is not the typical units of measurement for quantifying light in space. Any help is appreciated.

Suppose two spaceships originate at the same point on the x-axis and go in opposite directions, each moving at 0.8c. I would think that relative to one another either one would be moving at 1.6c. I know SR/GR states this is impossible. Why?

I sincerely appreciate all the help that everyone has provided in helping me to understand this subject matter. I believe I am finally beginning to get more of a grasp on it and it is the most bizarre theory. If it possible for a theory to be both correct and insane at the same time, then surely SR and GR meets the criteria. (assuming they are correct)

Cap'n Refsmmat, I certainly don't believe I am referring to the doppler effect.

Consider the twins paradox which states that one twin returns to earth actually being much younger than the other twin. When time actually slowed for the younger twin, what actually was occurring to the movement of the particles that compose him? Were the atoms jiggling slower compared to the twin on earth? I have no idea, but this is what I am trying to understand.

I really can't speak to the topic of atomic clocks, because they have the disadvantage that their mechanism is not apparent as it is with the ideal light clock. But with the light clock, by the very nature of the mechanism, the ticks will be less frequent from the arbitrary observer's point of view and the slower time is merely a definition of the clock itself.

In the case of an arbitrary observer looking at an ideal clock on a spaceship (composed of two mirrors, incrementing every time the same photon bounces back and forth), it is no mystery why the clock ticks slower. The light has to go a longer distance because it has a horizontal movement added to its vertical movement. As far as the arbitrary observer is concerned, a longer distance (lightpath) with a constant speed of light means the clock ticks slower.

There are many clocks that tick slowly. How do you decide when this means that time is moving slowly and how do you decide when this means that the clock is broken? In the context of the previous conversation regarding an arbitrary (randomly chosen) observer. If the observer has his own clock and sees that the clock on the spaceship is slow, shouldn't the observer come to the determination that the spaceship's clock is broken? And if the observer suspects that this is not a "typical" case of a broken clock, shouldn't the observer be able to look to the underlying mechanics of the clock to determine what is going on? Isn't it vital to be able to determine if a clock is only representative of itself or if it is representative of the system in which it is in. This is the deeper meaning of time that I am trying to understand and am asking for help in understanding.

Yes, as you stated, the arbitrary observer should have their set of the universe's position data generated according to their own clock - I didn't intend to suggest otherwise. So what exactly then is meant by SR and GR when it states that when an object moves fast relative to the arbitrarily observer, the arbitrary observer (who has his own valid clock) sees that the fast moving objects time has slowed down? To the arbitrary observer, his own time is the time, and the position of the fast moving object exists for each moment at his time. Does this mean the arbitrary observer views the fast moving object's atoms as jiggling slowly - would this mean the arbitrary observer would view the fast moving object as having a low thermal energy? Part of my difficulty in discussing the subject matter with clarity is that Einstein in my opinion really never gave a definition of time - to me, he basically sidestepped the issue by discussing clocks. Therefore, I am trying to understand the meaning of SR/GR when it states that the arbitrary observer sees a fast moving object as having slower time. To the arbitrary observer we have been discussing, his time using his clock is the time and the notion that he views an object of having a slower time is something I need clarification on.

md65536, I need to think about the cyclical reasoning, but regarding the Turing machine recording the state of the entire universe at a single time - yes this is definitely a fundamental part of the machine I am describing. Choose any observer's point of view (irregardless of whether one observer's view is any more correct than any other observer's point of view). For a randomly chosen observer, shouldn't there be a complete set of data describing the positional state of the universe because at that moment for that observer isn't his position compared to every other particle in the universe fixed, thus providing a complete positional data set for said observer. Philosophically restated, from the point of view of any observer (pick whatever one you want) doesn't the entire universe exist at once? If so, let this observer's position data about the universe be provided to the Turing machine for the current state. And if there is not a complete set of data for any particular observer, exactly what does this imply about the universe - doesn't the very idea of the existence of a universe for any given observer imply a complete data set for that observer?

swansont and anyone else who might be of assistance, I have been considering this point you make about the mathematical definitions that Cantor developed for comparing different types of infinity, specifically as it relates to line segments. In a deep sense, Cantor is correct that any two line segments have equivalent amounts of infinity, for if you zoom in or zoom out on a line segment, one can see that any line segment of any proposed length has the same internal relationships of all of its parts to itself (in this sense, when thinking about infinity in this relational way, the specific values for the endpoints are quite irrelevant and quite meaningless). However, if one does not have the option to zoom in or zoom out on the line segment, say because there is another line segment to be considered because both are measured in the same units. In this case, a line segment of length one clearly cannot contain an exactly equal amount of points as a line segment of length 10 (Since one could place the small line segment on top of the long line segment which necessitates a one-to-one mapping and the long line segment would still have a length of 9 which is not covered by the small segment). In the physical universe (which is not just a single line segment), but deals with line segments of a set unit and the relationship between line segments and everything else in the universe, I would argue that Cantor's notion of comparing infinity is not adequate. In physics, I believe the values of the end points of a line segment are crucial in comparing the number of data points contained therein explicitly because physics has the inherent practical purpose of comparing things in the universe. Just as the values of the end points matter, I would argue that the density of data points contained therein matter as well. So, if time slows for one object relative to another, then there cannot be pragmatic (for comparison in the physical universe) one-to-one mapping unless the second part of my proof holds true. And if one asks why it matters if there is a one-to-one mapping of data points (what does it matter if the object going slower in time has a null value for some data points), I would argue that the very ability of physics to make comparisons at a very fundamental level is attacked if one accepts null data. This is a very real shortcoming of Special and General Relativity because a primary goal of physics is to make comparisons at any level and an acceptance of null data muddies the waters in which to make those comparisons. In this sense, Special and General Relativity is at the very least contains major shortcomings (and at the most is simple incorrect).

Baryon, Swanson, and anyone else who will help, Alright, this is quite fascinating for me and I really appreciate your help. I accept the idea that there may indeed be infinite points in space and that it may be essentially possible to jump from one point to another (part 1 of the proof is flawed), but doesn't part 2 hold water anyways. If time is going slower for object A than for object B (because object A is moving fast relative to B), both of which are part of universe U, doesn't this mean that there must be positional data sets available for object B at which object A would be forced to have either null values or sequentially the same values? And aren't the inherent contradictions of both of these possibilities, that object A either does not exist (contradiction is object A does exist) or object A is not moving (contradiction is that object A is moving fast relative to B which is why it's time is slower) still proof that Special and General Relativity are incorrect?

I am lost. What is a false dilemma? Also, I thought you were suggesting that that if you need to get to points in a sequential order along a line was the part of the initial assumption that was wrong. What part is wrong?