# Tag Info

1

Where is the flaw in my thinking? In your concept of time. It's little more than a cumulative measure of local motion, see A World without Time: The Forgotten Legacy of Godel and Einstein]. Your macroscopic motion relative to some other guy results in you measuring his local motion to be slow, whilst he measures your local motion to be slow. This sounds ...

4

To measure time, a duration, you need two moments – when you press "start" and "stop" button on the stopwatch, respectively. But because the two objects are moving relatively to each other, it isn't possible for them to "meet" at both moments. If their locations coincide at the "start" moment, for example, so that their clocks may be compared at this "start" ...

-2

if A and C are moving at equal velocities 5c then they should meet B at the same time ,If the stationary object B stands at the mid point of the motion path then A will cut the track to B at 5c and C will do the same so suppose that half the distance is 5 kilos then Then both A will meet B and C after 1/c time ..so the velocity each one will see the other ...

0

Consider a spherical symmetric mass distribution in space, located around the origin of a coordinate system. One can forumlate a stress-energy-tensor $T^{\mu,\nu}$ for this situation. Solving the Einstein-field-equations for a reference frame, in which that mass distribution is not moving one obtains the Schwarzschild-metric $g_{\mu,\nu}$. One can now try ...

0

I can only answer your first question due to time constraints: To me the phrase "interaction cannot be allowed for" is a roundabout way of saying they cannot determine the photon's exact momentum for use in the related equations.

0

So far the only experiments done are “near” Earth. There, objects that are in lower gravity, underwent acceleration and high speed have shown time dilation as predicted by special and general relativity. Gravity at least does seem to be a factor here but exactly how much is unclear. I am afraid we would have to go ask Jack and Jill to answer this question. ...

0

The clock isn't slowed by any force, the clock is only slow from Jill's perspective due to his immense speed. From Jack's point of reference he is not moving and Jill is speeding away from him and her clock is slow.

0

There is no "correct" speed. All speeds are relative to the observer, but this does not mean you can watch something moving faster than light even if you are moving one way at 0.6c (60% the speed of light) and someone else is moving the other way at 0.6c. Even though typical logic would dictate that you see each other move at 1.2c (20% faster than the speed ...

2

Short answer : the same light goes at the same speed (c) relative to any observer. There is no grid. This is counter-intuitive : if you're standing in a bus traveling at 30 mph and you walk at 3 mph towards the driver, you walk at 30 + 3 = 33 mph relative to the road. But that doesn't work for light : if the bus travels at c/2 and you shine a flashlight ...

3

Suppose we play a racing game. I scatter a little bit of dust around space, then you come by me in your spaceship at some speed $v$. Let's start with $v = c/2$, just so we're not contentious. Right as you pass, I fire a really bright laser pulse in the direction you're going. You're racing the laser light. The dust means that you see reflections of it, so ...

2

It's relative to all inertial reference frames--in special relativity the coordinates of one inertial frame are related to the coordinates of another by the Lorentz transformation, and this transformation has the property that anything with a coordinate speed (change in coordinate position divided by change in coordinate time) of c in one inertial frame will ...

4

No, for several reasons. First, the idea of time "slowing down" is a little bit of a misnomer. If you were traveling at relativistic speeds, you would not perceive the passage of time any differently than you do right now. It's only when you compare your clocks to an observer in another reference frame (let's me, sitting in my living room, at rest with ...

2

Its not possible to stop time but using relativity it can be thought of to be slowed down . Nothing can be faster than the speed of light so its not possible . Even when we near it , energy tends to become infinity .

1

Things will be bigger/smaller/slower with speed as $\frac{1}{\sqrt{1-\frac{v^2}{c^2}}}$. Thus, as $v \rightarrow c$, Mass (or energy) goes to infinite, Time goes to zero. But it is only a limit, which is unreachable (at least in the special relativity), because of (1).

2

The coordinate velocity does indeed change discontinuously, but only if the acceleration changes discontinuously i.e. the jerk is infinite. Since for any physical system none of the time derivatives of position can be infinite, in a physical system the coordinate velocity can't change discontinuously. But let's ignore this for now and examine why we get a ...

Top 50 recent answers are included