Relativity

I am no scientist I just don't know where to ask this silly question that has been on my mind. I made an illustration, but cant find any way to upload to the forum. The link is below http://tinypic.com/r/29clzrd/9 Any feedback would be awesome. Luke

When the universe was in the hot, dense state, was everything causally connected and the time, if it existed at that point, was the same everywhere until inhomogeneity occured i.e. space formed and photons/information could travel? Edit: Might be in the the wrong forum; I just realised Relativity goes awry at time-zero.

Another take on twin paradox: One twin is living in a tower on Earth and the other is flying around the Earth with constant, high, speed, at the same level with the "tower twin". Both are using very accurate clocks with 2 displays, one normal and one very big. Now, the plane with the flying twin gets very close to the tower every time it completes a full circle around the Earth and both twins are taking pictures with both plane & tower cocks in the same frame/picture (remember the normal + big displays). The question is: would the pictures taken show time dilation only for the other twin/clock or the pictures would agree in showing time dilation only for the twin/c…

Okay, there is a similar question but not precisely mine. Imagine a stationary observer a and two objects x & y going away in opposite directions at .25 c. A sees time slowed on x and y. X sees time slowed on a and y. Y sees time slowed on a and x. ??? How can they all see time slowed on the other?

Idk if this has anything to do with relativity Maby it does but I thought I should ask if it takes a year for example for light to travel from one place to ours then we are seeing 1 hour into the past of that planet therefore would it add more proof to the idea that the future is predetermined?

Would it be true that the present only exist's locally to an observer because of the nature of light and its finite speed only allowing delayed images of observation?

We know (measured) that a clock at sea level "ticks"slower than a clock on a mountain. As we get higher, the clock runs even faster. Now, if we go much higher, towards the Sun, the clock should begin, at some point, to run slower, influenced by Sun's gravitation. Where is that "point", at what distance from Earth? It was calculated and/or tested experimentally?

I'm having a tough time getting a laypersons understanding for the differences between: covariants, contravariants, invariants, and variants as they relate to Lorentz transforms in the field of Special Relativity. An intuitive definition for those terms would be wonderful, but I'd be extremely grateful even for some examples of each. They don't need to be limited to the field of SR, but if outside of that field such as a references to GR instead, please be sure to list it as such. Thanks.

It seems pretty well agreed upon that shadows can 'travel' faster than speed of light, because a shadow is not a thing, and carries no information- it is simply the absence of light. One could pass a shadow puppet across the surface of the moon at faster than light speed by moving the puppet across the beam of a spotlight on Earth quickly enough. Like the rim of a bicycle wheel traveling faster than the hub, the angle subtended by the shadow is preserved. My question is, does this require a quantum mechanical explanation? It seems to me that it does: the hand puppet isn't objectively blocking the waveform of the photons moving towards the moon, only affecting the prob…

I am thinking that the boundry set to objects moving thru space time can not exceed the speed of light because they exude a gravitation field which holds them into relative space time and can not move any faster because the space they are moving into is created at that moment and at the speed of light. If i am correct in my asumptions i might have an intresting idea about what gravity may be Please comment

Hello, i like space related topics and i've been looking for an answer to a question i thought of. Can time feel faster for some creatures or in some places in the universe? Is the rumor about a year for a human is seven years for a dog true? Thanks.

I've been doing some research into Einstein's equation E2=(mc2)2 +(pc)2 but apart from in nucleur reactions, where you can use the simpler E=mc2 as momentum=0, I have been unable to find any applications. Thank you in advance

Redshift and Blueshift tell us something about the motion of far distant galaxies, but it's only a rough approximation. It only says something about the motion directly towards or away from us. Nothing more. Could this method be used to give an accurate measurement of velocity, even from millions of light years away? If an event is timed by a clock that is stationary in it's frame of reference, (call the result T), any other clock that is NOT stationary in that frame will measure a time greater than T for that event, as it' will observe the event happening slower. So, if we find a pulsar in the far different galaxy, and accurately measure the interval for a th…

Imagine a stick of wood that was 1 light year long. There are two people holding it, one on either side of the stick. Before I proceed to my questions about this scenario, I would like to clarify something: In another thread, I was told that one person moving the stick wouldn't be instantaneous on the other end, but move at the speed of sound because of its elasticity. At first, I didn't understand this remark at all but I think I do now. I think what they mean to say that the stick would be very, very thin relative to its length so that it wouldn't be sturdy when held from both ends. I was thinking of a much wider stick. Imagine the length to width ratio of the s…

If a rocket is traveling with almost the speed of light, the static observer "can" see that the time in that rocket is dilated, i.e. things are happening in a slower rate. Very very close to c, time dilation gets bigger and, from the static observer, nothing appear to happen in the rocket. It's like everything freezes. Well, photons are travelling with the speed c but they appear to exhibit/produce rapid oscillations/variations: a change in the electric field creates a changing magnetic field that in turn creates another electric field and so on. How is this possible? At that speed it should be no change at all, according to special relativity.

This has been verified experimentally and it seems that any effect exhibiting this invariance and a finite speed could be used to derive the Lorentz Transformations. Is there any way of showing that this invariance and finite speed must be the case or does one just accept observations as they are and proceed from there? https://books.google.ie/books?id=WTfnBwAAQBAJ&pg=PA44&dq=Rindler++speed+limit+cosmology&hl=en&sa=X&redir_esc=y#v=onepage&q=28.2&f=false page 43

In general relativity, gravity isn't really a force, it's just the bending of space time. So I guess, in a sense, he would say zero force. Someone correct me if I'm wrong. I actually think he's asking a different question. I think he's asking something like this: If a mass appeared out of nowhere, how long would it take for it to bend all of space? I would guess instantly because it is mechanical. The same way that moving the end of a 1 light year long stick would be instantenous, instead of taking 1 light year. But that's not really a valid question because, as far as I know, no gravity has ever appeared or disappeared after the big bang, so even th…

We have an infinite (thin)(flat) plate. 1. Newton is standing on the plate. Does he feel a g-force? 2. Einstein is standing on the plate. Does he feel a g-force? 3. madmac is standing on the plate. Does he feel a g-force (madmac is an aetherist). And, are these three g-forces (a) zero, or (b) mansized, or (c ) very large, or (d) infinite? I have my own ideas re the theoretical answers. But i am interested in other's ideas.

Simultaneity - Albert einstein and the theory of relativity. This video says that the person on the train will see lightning from front of the train first. But what if we take it that the train is stationary and the earth is moving below the train. How could we tben explain the passenger on the train seeing the front bolt first

I have been through following papers for research: 1)http://cdsads.u-strasbg.fr/cgi-bin/nph-iarticle_query?1990ApJ...362..584M&data_type=PDF_HIGH&whole_paper=YES&type=PRINTER&filetype=.pdf 2)https://arxiv.org/pdf/gr-qc/9905054.pdf Conclusion of the second paper given above states the following: " In this case the external action (the gravitational wave) amounts to a time variation of the frequency parameter of the initial system (charged particles in a magnetic field), so that in the overall system the equilibrium at rest (x 1 = 0) is unstable. Any deviation from this state, however small, is sufficient to lead to a rapidly increas…

I printed off a copy of an English translation of -- On The Electrodynamics of Moving Bodies (June 30, 1905). I read it over a few days, to see what Einstein said about his train-thought-experiments. Alby didn't mention any train experiment of any sort. There was a mention in Chapter 1 to explain the physical meaning of simultaneous events, here Alby says -- "That train arrives here at 7 o'clock" -- which he says means -- "The pointing of the small hand of my watch to 7 and the arrival of the train are simultaneous events". No experiment here. And in Chapter 7 re Doppler etc Alby mentions a -- "wave-train". Nothing to do with choo-choo trains. My copy is 24 …

Our teacher was explaining us relativity history when one of my coestudents made an interesting question: Wouldnt the huge sun helium atmosphere cause refraction and hence move the star any way? The teacher seemd lost to this question but soon he answered that Einstein knew the exact amount of refraction and accounted for it to measure gravitational lensing So my question is how did Eisntein know the exact amount of refraction caused by the sun atmosphere if it hadnt been measured before and how did he distinguished it from gravitational lensing And how much of the movenment of that star during that eclipse was due to suns atmosphere refraction and how muc…

According Einstein the gravity is caused by curvation of Spacetime. I understood that the formula of this curvation is the Riemann curvation tensor. So should this formula with the proper approximations result in Newton formula of gravity? Or how is it mathematical proven that gravity is caused bij curvation?

Light cannot escape from black hole = Escape velocity of black hole is greater than the velocity of light = Anything that falls from the space into the black hole hits the black hole with a velocity greater than the velocity of light. Isn't that possible?

now check this one and i will modify after i get your questions Links deleted by mod