Sr Definition and 477 Threads

A spaceship is moving, then it launches a ray of light behind itself. if time in the spaceship is slower than in other frames that are moving less fast, shouldn't the ray appear much faster than c? this thing works with a ray launched in front of the ship, but behind, shouldn't the time go...

Is it possible substitutive explanation of SR: "because of larger relativistic mass everything moves more slowly." I tried to to get this substitution mathematically, but it not works. I know that lorentz contraction should be included as supposition that things work. For instance: a =...

As we know for over 100 years magnetic force in an relativistic effect caused by the movement of charged particles. Let’s take the standard example - current in a wire. If a charged test particle (say electron) is moving relative to the wire it feels the Lorentz force. I can understand...

Let's say we have a ship following a buoy toward earth. The ship and buoy are at rest relative to each other, a distance of 10 light years apart, in the ship's frame. The distance between the ship and buoy is 5 light years in Earth's frame. They are approaching Earth at a relative velocity of...

Hello, I have a question about special relativity. According to the Lorentz transformation, if a coordinate system K' is moving with respect to a coordinate system K, then a rod fixed with respect to K' will appear to be more lengthy with respect to K than that with respect to K'. The...

OK, can someone answer this for me? Let's say we have two spaceships, Ship A and Ship B, traveling toward Earth at v= 0.866c relative to earth. They are at rest relative to each other, not accelerating, and Ship B is at a distance of 5 light years behind Ship A (as observed by them). They...

The usual foundation for deriving SR is the constancy of the speed of light. Are there other ways to derive SR, and eventually some more general? Have you ever read something about that? Thanks, Michel

I'm coming at this from the perspective of something that might be used in a general discussion piece on SR, or maybe the introduction part of a (low level) course. One concept that's often difficult for newcomers to grasp is the lack of a 'God Frame'. It comes up in several ways, one of...

The fundamental mistake in SR is making a direct comparison between the movement of objects and the movement of light. If we take into consideration the fact that the light simply can not have a zero speed, these are different. Maybe there is a more profound explanation of why this...

The other day, I was trying to explain what SR & GR were for some non-science friends of mine. I started speaking of motion with constant speed, the postulates of SR, the spaceship and the ball, time dilatition, twin paradox and so on. Needless to say, they didn't understand what I was talking...

If SR were wrong, in what kind of difficulties and paradoxes would we run? What would an universe with instantaneous signals look like? Is such universe even possible? thanks

In normal mechanics, the kinetic energy is the integral of the momentum with respect to the velocity ( \int m_0v.dv . So, why is the kinetic energy not given by \int \frac{m_0v}{\sqrt{1 - v^2/c^2}}dv? Sorry it took a few edits to get the maths looking right.

I've read in multiple locations that GR is necessary to properly explain a co-rotating perspective/observer of the experiment. Additionally, SR can explain the experience of non-inertial observer. The above two statements seem somewhat conflicting and leads to my question. Why is it that...

Is it correct to think about SR as different observers using different coordinate systems depending on their speeds? This would meen that their measurements would differ since space, time, mass,etc.. measurements depend on the system used. I find it very easy to understand SR when I think...

Has anyone derived the Lorentz-transforms by using 'simple' geometrics? If so, could I get a link for the paper please. I tried to google for one but couldn't find.

I need to clear some conceptual doubts in the Special theory of relativity. So could anyone explain them in context to the following questions: 1. The speed of light in glass is 2.0 x 108m/s. Does it violate the second postulate of SR in any way? 2. A uniformly moving train passes by a...

Alright, so Einstein came up with SR to make Maxwell's EM consistent with dynamics, correct? But SR was only for non-inertial reference frames and ignored gravity, so it was replaced with GR to make SR consistent with gravity. So why have I read (from many sources) that Einstein spent his...

Why isn't the mathematician Henri Poincaré acknowledged as the true discoverer of special relativity? http://www-cosmosaf.iap.fr/Poincare-RR3A.htm http://arxiv.org/abs/physics/0408077

How has it been shown that time dilation is not a property of light? I've only seen the equation derived from a light clock or something dealing with light. How can time dilation (along with other predictions of special relativity) be generalized to everything as a property of time itself?

A quick question for those fast with the GR and SR math. Assume you get in a spaceship and start accelerating away from Earth, and during the trip you and the people left behind compare clock speeds periodically (not elapsed time, but rather tick rates). At what combination of acceleration...

I hope someone can point me to some information to assist resolving this apparent SR paradox. I have two gear wheels with an endless chain passing round them. The axles of the wheels are 100 chain_link_lengths apart, so we have 100 chain links along the top; 100 chain links along the bottom...

I know a bit about evidence supporting special relativity (muon decay, synchronized cesium clocks, etc.) and general relativity (perihelion of Mercury, etc.). BUT - is SR and GR considered "proven" or, in the minds of mainstream physicists, is the jury still out?

I've had a friend who said this "However, all objects can be considered immovable relative to the speed c, since the speed remains constant relative to all objects and so it seems like all objects remain stationary comparing with this speed." There's a nagging feeling at the back of my head...

I don't know how to reset the time on my clock, but I do have a spaceship that can go as fast as 0.9C. How fast and how far will I need to go this weekend to properly reset my clock. :smile: The Rev

I'm pretty new to the ideas of relativity, so maybe this is old ground to cover for some of you. However, I need to know how to resolve an apparent paradox. Person A is traveling at relativistic speeds holding a stone over his head. The stone weighs just slightly less than the maximum...

So the question is basically an unstable particle at rest breaks into 2 fragments. m1 = 2.50 x 10 ^ -28 m2 = 1.67 x 10 ^ -27 v1= 0.893c whats v2? So it gets to a point where they ahve... yxm2v2+ ((2.50x10^-28kg)/(sqr(1-0.893^2)))(0.893c)=0 Now why is that square root "1-0.893^2"...

In a recent discussion in this thread I wrote: Using classical mechanics and electomagnetism, work out the speed that an electron would have to have in order to orbit a hydrogen nucleus at a distance of 10^-12 m: F_c = \frac{m_ev^2}{r} = \frac{kq_e^2}{r^2} v = \sqrt{\frac{kq_e^2}{mr}}...

In http://www.freewebs.com/mouldy-fart/Space,%20Time%20and%20SR.pdf paper the author wrote: t'=\sqrt{\frac{4h^2}{c^2-v^2}}=\frac{2h}{\sqrt{c^2-v^2}} t'=\frac{2h}{\sqrt{c^2}}\frac{1}{\sqrt{1-\frac{v^2}{c^2}}} Why so? Also, isn't the relativistic beta considered just v/c, not as the...

What if I am in a RF, S, anchored to the ground, and there is another RF S', which is anchored to a train. According to my RF, the clocks in the train moves slower, but according to S', does my clocks move slower too?

-- -- EPR experiments seem to show a significantly higher correlation rate in the detection of separated photons which are in an entangled state. From the measured correlation we may or may not want to draw very fundamental conclusions. One such a far reaching conclusion would be that...

Came across an article of interest claiming SR implies the future is predetermined. The salient argument is summarized below: We start with the notion that we cannot attribute reality to the future since it is yet to be determined. Nor can we claim that what we see is real in the present...

I tell them: (first, explain spacetime) "Relative to anyone else, we move through space-time at the speed of light. Take you and I standing here, you are not moving in space relative me so I see you moving through time at the speed of light. If somebody flew past at near the speed of...

With the appearance of the general relativity theory, it became increasingly difficult for other disciplines to “map” their own terms of art to those of relativity in an internally consistent fashion. But we know now that, previous to the appearance of the general theory, it was attempted very...

I was reading about special relativity on How Stuff Works. In the article, the writer has given the following 4 points: 1. Energy must be added to the system to increase the ship's speed. 2. More of the added energy goes towards increasing the system's resistance to acceleration. 3. Less...

From John Baez’ page on the experimental basis of Special Relativity, he says that: and My question pertains to the remarks in blue: aether theories that are experimentally indistinguishable from SR. Where are these theories published? One member (Yogi) makes reference to the so-called...

It has been years since I have thought of relativity, but I came across a book by Jerome Drexler in which he attempts to support his view that ultra high energy protons (cosmic rays) are what dark matter is all about in the galactic halos. In spite of the fact that it seems to me these protons...

A train is moving to the right at v=.5c. Someone standing on the train throws a baseball forward (to the right) at u'=.99c (relative to him). Relative to somone on the ground, the ball appears to be traveling at a speed u which is slightly faster than .99c, but still less than c. What if the...

Please help me resolve this problem. Suppose we have 3 objects traveling at constant velocity, and hence 3 inertial frames of reference. Call them object A, B and O respectively. O is at rest with respect to the observer. Let the relative velocity of A from the point of view of B be speed...

Special Relativity predicts that moving clocks run slow, mass and length are variable and simultaneity is relative. These are 'real' phenomena and leads me to think that the reality of one observer (the passing of time, all physical properties and space-time events) can be regarded as 'his...

What if someone set up an experiment, where they sped up a mass of high density in a circle ethier by making its radius smaller and smaller, until the large mass is moving near the speed of light, then at an extremely small highet above this rotating mass you set off a high frequency laser...

What are your favorite web pages on special relativity and why? I'm looking for exemplary pages that represent orthodoxy and excellence. Thanks. Photon A

what are some of the experiments performed that upholds the predictions of SR?

This is a question in David W. Hoggs SR Book, so it is not homework. Problem 3-4 A rocket ship passes the Earth at speed B = 0.8 (B=v/c). Observers on the ship and on Earth agree that it is noon. Answer the following questions: a)At 12:30pm, as read by a rocket ship clock(assuming it is...

could someone be kind enough to explain to me why the fundamental postulates of special relativity introduced thanks

Is this a paradox between QM and SR: If two particles say electrons are in the same quantum state then no matter what the distance if one "flips" then the other one does the same thing, because they are tricked into thinking they are right next to each other, however SR strictly implies...

Hi, correct me if I'm wrong, but quantum mechanics and special relativity seem to fit pretty well together. With Klein-Gordon's equation and Dirac's equation anyway, they seem to be able to live with each other quite happily. Are there cases in which they can't? Is this what Q Field theory...

About that train experiment. Everyone probably knows the story. For the person on the train, the flash of light hits both ends of the train at the same time. For the person watching on the embankment, the flash of light hits the back end of the train first. Now, I'm reading a book on SR...

Basic SR question here. But Einstein said that the Speed of light is an absolute constant. Why then do we hear of experiments of laser light and some kind of substance used to SLOW light down to some ridiculously slow speeds? And how water slows down light too. Isn't that "violating" SR? If the...

Someone told me that the normal time dilation formula \Delta t = \gamma t_{0} is not correct and that the time dilation also depends on the distance (I'm not entirely sure of what). Is this true?

Does anyone know of a resolution to the bug and rivet paradox? It is outlined here: http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/bugrivet.html#c1 My first guess is that the rivet does not reach the bug, and the rivet's predictions are wrong because it undergoes infinite acceleration...