Relativity

who can help me explain this ? why is the darker color ? Clothing Loose-fitting long-sleeved shirts and long pants made from tightly woven fabric offer the best protection from the sun's UV rays. A wet T-shirt offers much less UV protection than a dry one. Darker colors may offer more protection than lighter colors. http://www.cdc.gov/cancer/skin/basic_info/prevention.htm

So in this instance I'll talk about photons. As light passes through a gravitational field its path is bent/deflected (however you want to phrase it). I can accept that. What bugs me is the how the particle will view its motion through space. From its perspective, is it travelling in a straight line? Or not? If it is, does the same apply to non-zero mass particles? (Protons, electrons etc.) All help is appreciated!

Does anyone know if a rotating plasma can also undergo time dilation? Been thinking off and on about how it might allow a plasma ball to last longer than one would otherwise expect. Just not sure what the math would look like for a rotating system.

Do we see the time passing at far a way galaxies (say 12 lightyears), and thus have a very fast growing distance, more slowly?

Does only lensing cause refraction of light in vacuum?Does gravitational or electromagnetic slowing of time cause additional refraction of light?

Brief mathematical proof, which shows in a clear way that the interpretation of the theory of relativity in terms of time dilation is wrong, is available on the link: http://dl.dropbox.com/u/26262175/TimeDilationIsFalseProof.pdf

Horizontal Speed is equal to speed of source agree or not

You know how in Special Relativity then there are things that happen to objects as they approach the speed of light? What would the effects be like when something has angular motion? For example, when something has a velocity close to the speed of light, c, then it's length contracts in the direction of motion. The length l'=l/γ (where γ=(1-v^2/c^2)^(-1/2)). I think it would just be how much it decreases in radius, but is that correct? And also with length contraction, you use the velocity of it relative to something else. The relative velocity that 1 object is relative to another v'=(v1+v2)/(1+(v1v2/c^2)), But what are relative velocities like with angular motion?

Reference http://en.wikipedia.org/wiki/Lagrangian Toward the end of the article is are sections titled, "Electromagnetism in general relativity" and Electromagnetism using differential forms". I happen to use forms. Though the argument is just as valid in the standard notation up to a difference in parity. Both are generally covariant. Through the usual method, we can derive maxwell's equation, and define electric charge assuming charge/current density is invariant with respect to the vector potential. This is somewhat disappointing. Rather than obtaining the dynamical laws of electromagnetism, all we seem to get are maxwell's equations. However, the …

So I got completely confused in this other thread... Suppose an observer moves along the x axis in some known way at speeds where length contraction is significant. Is it possible to synchronize the movement of another object on the x axis, at some distance from the observer, such that the object always appears the same distance away according to the observer? For example, suppose the observer and object are relatively at rest separated by 1 light second, and then at a predetermined time the observer moves in the direction of the object at v=0.866c for one second (with negligible acceleration time) and then stops. Is it possible to move the object in such a wa…

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To keep it as simple as possible, we will use only the right half of E’s train example. O1 -----------------------------------------------<~~~~~light O2--> A light ray starts equidistant from inertial observers O1 and O2, as shown. And yet O2 sees the ray before O1. (And this is absolutely before because these are light-like events.) Why this difference? I’m guessing that is has nothing to do with either the event or light’s speed, but that it has everything to do with the fact that the observers moved differently in relation to the approaching light ray. But this does not show that simultaneity is relative; it merely shows that observers movin…

A typical objection to the equivalence principle is that you can tell that you are falling in gravity because you can see that an item falling alongside you compresses horizontally and stretches vertically. However, this results from tidal effects of non-uniform gravity, whereas Einstein stated the equivalence principle very clearly to apply in the case of homogeneous (that is, uniform) gravitational fields. See post here, http://www.scienceforums.net/topic/79255-distinguishing-between-acceleration-and-gravity/?p=772228, and Einstein quotation from 1907: We consider two systems S1 and S2… Let S1 be accelerated in the direction of its X axis, and let g be the (tempo…

Simple computer program that enables a quick and easy verification of the theory of relativity is available on the link: http://dl.dropbox.com/u/26262175/VerificationTheoryRelativity.xlsx The program calculates the delay of the clocks in motion for any speed of timing pulses in these clocks. Very interesting results of the calculations are obtained for example for the pulse rate: 10 m/s, 250 000 000 m/s, 290 000 000 m/s and higher.

First, define terms: Time dilation is said to take place due to relative motion. Not the actual forces of acceleration. Thus, two space craft floating by each other in space will each see the other's clock as moving slower, and assume their own clock is moving at the correct rate. Any objections so far?

Here is the abstract to a paper I wrote: Non-Euclidean Electromagnetic Kerr Model for Hydrogen Abstract A Balmer series of observed hydrogen data was compared to two geometric levels of atomic theory and modeling. The first theory compared was the Euclidean based (Minkowski metric) special relativistic Dirac theory, with QED corrections added. The second theory applied was a non Euclidean electromagnetic (EM) Kerr field theory with Euclidean QED corrections added. Each model was used to predict the Balmer series transition wavelengths, and then compared to the observed wavelength data. The statistics (sample averages, standard deviations) for the model performances were…

Hi, I've been reading recently on the, let's call it famous, Andromeda paradox stated by Riejdtnik/Putnam. So I understand what happens, or why the motion affects plane of simultaneity, but I don't understand why is there such a big time lapse between what's happening on the Andromeda galaxy right now according to the observers. It is clearly stated that because it is distant, the lapse between events is huge (about a day if they are walking slowly). So when we compare it to the train experiment, when the difference is only a few seconds, it seem confusing. What role does the distance of event to the observer play here, and how does it affect the judgement of the temporal…

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This applies only when the curvature of space-time is Euclidian. In real universe however there is no flat geometry anywhere in the universe, therefore this symmetry is always broken. And twins can always synchronize their clocks in real time and they can observe whose clock is slowing down due to uniform motion. More clear example is that GPS satellite can always synchronize its atom clock with Big Ben and therefore we can say that the clock of GPS satellite is slowing in real time. GPS satellite is in uniform motion, but it travels in curved space-time.

I'll try this again! What's important in the twin paradox, which results in the asymmetry between the twins, is that one of the twins remains in an inertial frame while the other uses primarily two different inertial frames. It is tempting then to think that a mechanical switch between the frames somehow "causes" the relativistic effects---and further that the only way to switch frames is to accelerate---but this is not true. This can be shown by running the experiment with 3 moving clocks, none of which needs to accelerate during the experiment. Start with 2 passing clocks, A and B, which are each set to zero at passing. Let B travel some distance at v…

Photon energy-momentum is just relative thing.Doesn't it make any paradox?

Hi, I can't figure out why two protons that are stuck in a nucleus are lighter than these two when they aren't stuck in a nucleus. m(p+) + m(p+) > 2p+ Are they loosing something? Is something in them that is expulsed? Why can a proton be lighter than a proton?

Hi guys, I'm relatively new to this topic and website, though a thought just occurred to me. Could anyone offer any views on the idea below? The there are so many forces between matter, and matter (mass) and energy are interchangeable/different manifestations of the same thing. So is there a force of interaction between energy?

For whatever reason, this post is causing me to be accused of being someone I am not etc. However, in different forums a correct answer was not given to this problem. Also, I am not sure if this forum allows questions like this to be asked. If not, just remove it and this is fine. Anyway here it is. This is a modification to the train-embankment experiment. I am hoping someone can solve this problem. Assume when M and M' are co-located, lightning strikes their common location. There is also an observer B' in the negative direction of M’. After some time elapses in each frame, B' and M become co-located. Considering only the negative and positive x directions, t…

What is time? Some people think of time as a human concept, but to me it seems as if time, to some extent, is woven into the fabric of space. If it weren't, how would space warp time? Someone on the boards(don't remember who) said that time is the direction in which entropy increases. I can't imagine a world without time. If someone/something were to live outside time, what would it be like? Would there still be cause and effect? When I look at it from that perspective, it seems as is time exists only in our heads. :shrug: