Relativity

if ive read and watched correctly, einstein concluded that you can esseintelly travel back in time, or at least ''escape'' it, by travelling at the speed of light. how? i watched a thing on the history channel were there was an astrounaught on there, who had a twin brother, and when he went in to space, he went so fast that he is now actually like .511 seconds younger than his brother now. how? can anyone help me out here?

if you have a propeller spinning fast enough SR says time dilates with velocity so you get a gradient of time(s?) between the hub of the propeller and the tip. does this mean the propeller is bent in time? if it is bent, could it somehow be frozen in that bend so it remained curved after it stopped spinning? would such a thing bend space?

From my understanding, it seems that stopping time would be like reaching light speed with matter (like .75c + .75c = .96c). Relative to Earth clocks we can almost stop time as we increase relativistic speeds close to C. We can also almost stop time relative to Earth if we could put a clock on a black hole. So I think that a black hole traveling at relativistic speed would just have a very very slow clock. Is this in the ball park? I have been looking for a gravity time calculator but so far have not found exactly what I want. The "space math" site has everything but what I want. I would like to compare earth clocks to different g forces. Would Gravitation…

Einstein claimed and proved that it is impossible for an object of non-zero rest mass to reach the speed of light, because it will require infinite energy to get it there. Does the same apply for camera framerates? In the unknown future, could a person with sufficient technological and scientific education and a sufficient budget create a cam corder that is 299,792,458 frames per second, so that a person can actually watch a light bulb luminate a room?

some scientist , during LHC experiment said that if we try to move the proton with the speed of light, it would be so heavy that it wouldnot reach the speed. is it possible?? if it was why does light exist??

At 186,000 miles per second it takes 500 seconds for light to reach us from the sun. Due to time dilation from gravity, clocks on Earth, the Sun and in 0-G in space would run at different times. (1) Which clock would show 500 seconds? It seems that light would travel at a constant speed but only relative to its current location considering gravity. Also, (2) would an observer in space see the speed of the light beam change as gravity changed? To prove general relativity we observed light being bent around the Sun. (3) Is space actually warped from gravity or is time dilation from gravity causing the bend?

After reading several articles on time dilation and inertial frames I still have a question. The "Twin Paradox" at http://www.phys.unsw.edu.au/einsteinlight/jw/module4_twin_paradox.htm Made it sound like the acceleration and deceleration is what caused time dilation. That clocks in two inertial frames would stay synchronized as long as they were at rest in their frame, even if they were separating (without power) from each other. I must have missed something because "The Universe" Program pointed out that GPS satellites had to adjust their clocks because of their orbit speed using SR. Wouldn't the GPS unit on Earth and the satellites both be at rest in their own i…

Having a Problem with warped space time Please tell me if i am wrong, in Books, mags, and on TV and videos i have seen the same diagram over and over again. they show a planet of large object that is warping the space time fabric like how a lead ball would warp the fabric of a trampoline. The Object warps the space time fabric in one Direction and that's it. My problem with this diagram is that in space there is no direction, you cant say this is up this is down and so fourth. Direction in space can only be relative, meaning you cant have direction until you make something your source of reference for direction. so i come to this concl…

Is it possible? I thought of this when we were doing applications of integrals today (disk method, shell method bla bla) in calculus class. I was trying to figure out how you could get a negative volume. Would turning spaceitme inside out make that possible?

Are we, that is the earth, freefalling through space thus enducing the effect of weightlessness. Just wonderin if anyone knows. thanks

When I first learned about black holes in a documentary, they said you could not realistically approach it because the gravity strength increased exponentially by the millimeter, or something to the effect that parts of your ship would crumble away forward one layer at a time by the sheer difference of gravity between the ship's nose and its tail. But nowadays I read about objects never reaching the black hole, and instead of a "tug" on the ship, the gravity is really just space being warped thus forcing a traveler along a slow circular descent towards the black hole. Which doesn't sound as if what I learned previously is valid anymore. Will someone illuminate m…

For some reason, I had been under the mistaken impression that the Michelson-Morley experiment had determined that the general concept of an ether was no longer viable and warranted no further consideration what-so-ever. I’ve recently found out though, that the Michelson-Morley experiment had only determined that a specific form of the ether-concept could not be true. Namely, that the ether was a stationary matter that the earth passed through. I was surprised to learn that Einstein, in 1920, continued to comment on the ether after the Michelson-Morley experiment. “It may be added that the whole change in the conception of the ether which the special theory o…

When light goes through different materials, it chooses path to locally minimalize distance - it's trajectory is geodesic of some metric (usually diagonal - isotropic) . It is the result of that microscopic structure of the material can reduce wave propagation speed. Microscopic models of physics usually assume that we have some field everywhere and it's fluctuations transfer interactions/energy/momentum. So maybe these microscopic structure can reduce waves propagation speeds? Reciprocals of these velocities creates (anisotropic) metric tensor (g) and so for example particles travel through geodesics like in general relativity theory. Standard interpretation o…

Light photons inertia? what is the relation of the three things?

If Space-Time is curved,where does the vacuum fit into all of this? Is it fair to say,that a ball 'rolling' around the Sun,must have been a fair amount of logical acrobatics on Einstein's part,but it still remains to be said that the warping could be in any direction,and not necessarily horizontal? So,which way does the Orbit take place? Where is the warping? Why not have Vertically Orbiting paths? Have you seen the experiment where two spheres are hung from a ceiling by steel thread? The balls seem to attract. Could it be then, that circle and sphere are indistinct? And that could also account for warpage! Affirmatives.

Do Joules divided by Kilograms per Square Meter equal Miles per Hour? ie does E=mc^2?

Hello people, Just to bounce myself into the forum, what do you guys think about no micro system being absolute ? :-)There is no system or place in a system which is absolute, so that by reference to it we may determine absolutely the velocity of a movement. Yet to measure the movement of any system we must adopt a standpoint. This is Einstein's principle of relativity. Every observer of nature measuring phenomena takes a frame of reference and whatever frame he chooses it must be for him a system at rest. Thus just as we saw in Bergson's theory when we considered the subjective factor, or mind, or intellect, so in Einstein's theory when we consider the objecti…

Hey guys. I'm interested in knowing how you get to: [math]t = \gamma t'[/math] ...from: [math]t' = \gamma (t - \frac{vx}{c^2})[/math]

I was wondering since space and time are more dence around massive objects, does matter create space and or time.

Just thinking here. If two moving, and opposite, sources emitted a radio signal from distances x and y. Would you always see the light beams meet at [math]\frac{x+y}{2}[/math]? If you were in-between the sources and nearer to one?

This is a question that has been floating in my mind for some time now but because of lack of formal training and self taught mathmatical and science skills iv lacked a full out way of formulating this onto paper. Im sure many if now all here has seen the example of how space is expanding by the use of dots drawn on a ballon correct? Now every one stated how we can tell that the universe is expanding by measuring the distance inbetween each of those dots... This is where my confusion comes into play. the dots that one is measuring the distance in between are them self expanding at the same rate as the distance of the space inbeteen . If an observer is one…

Revising for Jan test; it's become apparent that my spec. rel. knowledge isn't watertight. I have a particular problem with questions in the following form. Anna is in a ship traveling at 0.8c; Bob is at relative rest. (At rest both the ships measure 100m). So, Anna whizzes past at 0.8c when the two ship's tails are next to each other the tail's clocks both read 0. Note: There is also a clock in Anna's ship's nose; Bob's ship has a camera next to Anna's ship's nose. (a) Where is Anna's nose relative to Bob's ship? This stuff is no problem. Lorentz factor = [math]\frac{1}{\sqrt{1-0.8^2}} = \frac {5}{3}[/math] So, [math]\frac{5}{3}*100=60m[/math] (b) Wha…

SIMPLE THINKING Changing the perception of time isn't traveling in time Let's say seven years ago a young man who was born on 11/September/1971 and on his 30th birthday was watching TV and was shocked seeing the airplanes hitting the trade center in USA "Events of 11/September/2001" & he thinks he could do something about it because he owns a flying machine which can approach a speed double the speed of light... He decided to travel in time trying to change what happened He puts a clock on top of TV set & synchronizes it with the watch on his hand & took the flying machine "which travels at speed double the speed of light" & starts to fly away j…

Suppose you have a rod of material that was 1 light-hour long (whatever distance that would be) and at one was was you, and another end was a big red button... If you pushed the rod from your end, would the button at the other end be pressed instantly, after an hour, or after an even longer amount of time? How long would it take the pressure to travel from your hand to the button?

Stanford has some Special Relativity lectures up on YouTube. Anyone else have some good online lectures?