question (Relativity?) (1 Viewer)

[paulio15]

Well to be honest with mass dilation it would be impossible to get this spaceship to the speed of light.

As soon as this vechile hit the speed of light it would have infinte mass.

And since kenetic enery = 1/2 mv^2 with mass being infinite and v being the speed of light. to get this spaceship to this speed you would need infinite energy, as in all the energy in the universe there for leading the the possible destruction of existance.

 

[bachinaminuet]

That is why I said that it was "completely hypothetical"...lol

An NO, the twins paradox is in a non-inertial frame of reference. The only reason the twin who goes off in the space ship ages is because she, or he, undergoes an acceleration. When the twin who goes off into space and reaches 0.99c and then turns around and comes back she, or he, is undergoing an acceleration in turning around and coming back. It is this acceleration in coming back that makes the two clocks actually differ and not just appear to differ.

What you are getting confused with is time dilation in an inertial frame of reference. The time dilation in an inertial frame of reference states that when a stationary observer on earth sees an astronaut in the space ship travelling at a constant velocity, the faster the astronaut gets, the more time SEEMS to slow down. Time isn't actually slowing down, it only is being perceived to be slowing down. Because if you think about it the astronaught would see the same affect with the time slowing down on teh stationary observer because they both have the same relative motion. And if time were really slowing down, whose was actually slowing down? NOBODY's because time is only slowing down from my stationary frame of reference when I look at the astronaut flying away from me in a stationary frame of reference and the astronaut's time in his/her own frame of reference would not alter.

Hope that helps =)

 

[undalay]

Sorry when I was refering to the twins i meant this:

Twin A blasts off into rocket (assume no acceleration)
Twin B stays on earth (assume earth is perfect inertial FOR)

Both twin A is both younger and older then twin B.

The only way the twins paradox can be solved, is if we apply general relativity, taking account the idea of acceleration.

However if both frames remained inertial, then the paradox would remain, whereas if non-inertial frames were the case then it wouldn't be a paradox would it?

edit: feel free to correct me if my interpretation is incorrect.

now applying this paradox to the satelitte.

Both the ray will reach and not reach. (inertial)

non-inertial frames = twins paradox not a paradox, that's all i meant.

 

[Rubes08]

Um here is my view. For situation one i think that it will both reach the spaceship and not reach it. As in, an observer on the satalite will see the spaceship travelling at the speed of light, but also see the radio signal travel at the speed of light. hence the radio signal will stay the same distance away from the spaceship.
However an observer on the spaceship will see the radio signal approach at c (i just realised that this might not be right due to the spaceship oberserver being able to reference to another frame, but i will continue anway), and the spaceship observer will see the radio signal catch up. i think thats wrong now but oh well

What about this one: THOUGHT EXPERIMENT neglect the mass increase and stuff like that. A person running with a gun that fires at 100m/s fires a bullet, so the bullet speed is roughly his running speed plus 100m/s right? So what happens if a runner running at c with a torch turns on the torch? Does an outside observer see the torch light travel at 2c? But this would break that C is a constant thingy? What if another runner (at c) was travelling towards the runner with a torch, would he see the light travel at 3c? Or would they all see the light travel at c in all cases?
Or what about if a runner with a torch is travelling in one direction and he turns on the torch in the opposite direction? what happens to the light?

 

[darkchild69]

Would it not depend on the frame of reference?