Relativity

Hi, This question (below) has always bugged me. I searched through the existing posts but just managed to confuse myself even more. It is often said that time slows due to gravity (I'm fine with this) but then they use an example "If I put a clock next to a source of gravity, it would run slower than a clock away from that gravitational source". I have a few issues with this that I would like some clarification on please: 1) I can slow my watch/clock or whatever, but it has no effect on time (though it works wonders for making me late). Likewise, speeding my clock up does not accelerate me into the future- so I feel there is some disconnection between how we m…

http://en.wikipedia....ster-than-light "If a laser is swept across a distant object, the spot of laser light can easily be made to move across the object at a speed greater than c." citation: Gibbs, Philip (1997). Is Faster-Than-Light Travel or Communication Possible?. University of California, Riverside. Retrieved 20 August 2008<br class="Apple-interchange-newline"> I don't get this... light can travel faster than light?

Hi all, 23 year old here new to the forum after watching an episode about Time on "Through the Wormhole" I couldn't quite bend my head around the concepts in the video and thought perhaps some of you could help out, I only hold a GCSE in Physics but I'm constantly intruiged and amazed with the field and find myself watching and reading things about it. My question is as follows: Understanding that time is relative to the speed of an object or the gravity surrounding an object and that time will appear normal to an observer stood in the moment looking at his surroundings even on the event horizon of a black hole, the documentary said that if a spaceship were to…

If we are in a rocket flying to the sun at 0.75C, why would we measure light from the sun AND light from earth to be C. It can't be because "moving clocks tick slower" for both cases, can it?

Hi guys! Before i begin, i apologize for my language, english is not my first language. After an introduction to the special theory of relativity during my mechanical engineering studies, i started to read some stuff about the general one. What i read was that energy deform the space-time continuum and that this property of the geometry of the space-time continuum was the new explanation pour the gravity instead of the concept of "gravitational force" that introduces Newton. Then, I asked myself the following question: According to the equation of einstein that link mass and energy, i though that the kinetic energy of a car going at a very high speed, let say…

I find this hard to understand, what is the space curving into? How can space be curved and yet appear flat?

Please look my short video on Youtube, which I recently put there. I hope, interesting. “Equation mc2 that we do not understand” . I want to know your opinion. Thank you. Stanislav Spassky. For those who do not know the physics very well. Einstein in 1905 found the so-called formula of the equivalence of mass and energy.That is, the body having the mass M has an internal energy E = Mc ^ 2. This is a great energy. In finding the formula Einstein used the Special relativity theory and the derivation was rather complicated and opaque ( difficult in understanding in essence). And all his life Einstein repeated that this formula is a consequence of the Specia…

Does the combination of Time dilation and Gravitational time dilation create an combined effect or do they act separately?

I've just watched a SR video on youtube It is a typical one showing a clock being 2 mirrors in a vertical tube of length C. The clock ticks when light bounces of each mirror, i.e every second. It goes on to explain that when the clock is moving horizontally, a stationary observer would see the light travel further, ie indicating time dilation for an observer moving with the clock. What seems wrong with that explanation is that if you had 2 identical clocks at right angles to each other, then would the stationary observer see the clock parallel to the motion have a longer period for when the light was travelling in the same direction, and shorter when at 180 deg. …

A small question I thought of recently: If the universe is the surface of a hypersphere, then what happens if an item goes 'around' the hypersphere and meets back up with the earth? Who will have aged more and why? (Assuming constant velocity and all that) Both will think that the other was moving and therefore slowed down, and each one would be equally correct. -Uncool-

What happens if GR's Effects got removed, especially that it has been being sensed to be changing through time - age? Away from the cosmological constant, Einstein's Equation are proven to be multiplied by a factor on one hand side. Refer to NASA's if the reader would like. There will only be SR's Effects. How would GR get structured? Or, there will not be GR from the Origin?!

Time dilation causes time to slow down relative to an object as it travels faster so relative to everything else the object is experiencing time faster than normal. would not this mean that entropy increases relative to the object in question? If so this opens up the idea that the energy coming out of the poles of black holes may not be from the vacuum energy but form the mass traveling into the black hole turning into energy via the vast amount of entropy done to it because of time dilation caused by the near speed of light velocities created by the black hole's gravity. please give your view on this thought.

If I travel at high speed towards a clock, do I see it as running fast? If yes, how does this square with the assertion of Time Dilation viz. "each observer sees the other's clock as running slow".

Okay, so energy is equal to mass times the speed of light squared. The problem with reaching the speed of light in a spaceship is that the more energy you gain, the more mass you will gain and you will slow down. http://zidbits.com/2011/04/why-cant-anything-go-faster-than-the-speed-of-light/ So why does the mass affect the spaceship in space if you are weightless?

I am a student at Bolton Sixth Form College. I am completing a project on "What will be the effect on science if the neutrino is discovered to be faster than light?" I would be very grateful if you could complete a short survey about this topic to support me in providing an up to date discussion of this area of science. To complete the survey click on the link below; http://www.surveymonkey.com/s/QMNF5QV King Regards, Prashant Mistry

a naive question probably, obviously the expansion of the universe now in proportional terms is very very slow (would be interested to know how slow, how much further would an object exactly a billion light years away be after a year), but presumably even objects much closer together are moving away from each other and we could in principle observe the expansion of space? if the theoretical expansion between two points is below a planck unit how would it occur exactly?

Interesting explanations with the surprising conclusions regarding the interpretation of the SR theory, are shown in the link: http://dl.dropbox.com/u/26262175/TransparencySRtheory.pdf Has anyone already seen it? What can be think about the explanations presented there? Can they be true?

Hypothetical theory allowing for the transmission of information to be passed between two points at greater than the speed of light. Or a theory about string (but not a string theory). Imagine a piece of string one au in length being held taught by two opposing spacecraft attempting to fly in opposite directions. If I cut the string in the middle, the two spacecraft will fly apart almost instantaneously, whereas from the middle, it would take four minutes for light to reach either spacecraft. alternatively I could just push down in the middle, both ships should instantaneously feel increased force pulling them backwards, faster than it would take ligh…

Im studying general relativity right now and I dont understand the equivalence principle. I understand it when relating to objects with mass. When in a sufficiently small space you cannot tell whether your are being accelerated in space far away from any gravitational force, or if you are in a gravitational field. How ever it states that there is no experiment you can do to tell the difference between the two, including a light experiment. This doesnt make any SENSE!!! I was under the impression light has no mass, which means when it bends, it is due to the curvature of space time or if you like a gravitational potential. Which means sitting on the earth light would bend …

As observed by AJB in a recent blog entry, Raa = gabRba = R Taa = gabTba = T R = -T Now, this site seems to say, that diag(gab) = (1, -1, -1, -1); and, that T = diag(Taa) = p ( c2 - vx2 - vy2 - vz2) = p (c2 - v2). So, T > 0 ? And so, R < 0 ?? In trying to calculate Rab, from the definition: I thought I found, that many terms cancelled, when one of the dummy indexes was set equal, to one of the formal indexes; that led me to an "einstein strike notation" that simplified the expressions, e.g. with a piece like: gba,b(gab,a - gba,a) - gba,b(gab,a-gba,a) wherein a dummy index a, b runs over every index, except a, b.

Thanks to IM Egdall who posted in another thread from this link emphasis mine Sorry I don't get it. What does mean "in second order of time"?

Hi everybody, How and why does mass curve space? Thank you.

Here is Differential Geometry Library, that has over 380 Exact Solutions of Einstein's Field Equations. The formulas are represented in different forms: metric from, Contravariant Newman–Penrose Tetrad, Covariant Newman–Penrose Tetrad etc. The library provides copyable formulas of the objects in different formats such as MathML for web-based articles, TeX for education or research works and Mathematica® and Maple™ input for calculations. So, hope it will be useful!

Hi all, So, Relativity says that the speed of light is the same in all frames of reference, but I can't get my head around it... Here's my question: 2 observers A an B A is riding a horse (why not?) at 1/2 c - B is stationary. A fires a laser at a distant target and measures the speed of light travelling away from him to be c B, our stationary observer also measures the speed of light travelling away from him to be c So lets say that the laser was fired while the two observers are at an equal distance away from the target and that from that dstance the light will take 10 seconds to reach the target from that point. Does that depend…

Um, I think I might have an idea on what gravity is. I'm not very experienced at physics and stuff, as I'm only in 7th grade, so I was looking up my theory and came across this website, so I decided to post it on here and see what everybody says. Okay, so here it is: If everything in the universe was continuously growing, expanding, and accelerating, could that be the cause of gravity? Like if you had a balloon, and you blew it up at just the right speed and kept blowing it up faster and faster, if you put something on the balloon, wouldn't it stay there, as the balloon would be pushing against it as it, (the balloon,) accelerated? Please let me know it there is…