i heard

basically what i was saying is that the dimension of time wouldnt allow u to go passed the speed of light if u tried.

Originally posted by grimreaper797
we still dont understand quite what u mean by threshold

Ok, this is my threshold question. Why do certain things happen at the speed of light but not other speeds? For instance: Two cars pass by each other at 60mph, they see each other as going twice that, 120mph. Now when these cars are going the speed of light and pass by they do not see each other as going twice the speed of light, instead they only see each other as going the speed of light. This is what Einstein stated. Where does the threshold exist to where this phenomena occurs?

And yes it is possible to travel twice the speed of light, again according to Einstein.

If someone on a spaceship travelling at close to light speed were to time the journey to a distant point known prior to the journey, it will appear to them that they have travelled faster than light.

Eg: It would not take someone travelling from earth 4.2 years at close to light speed to reach Proxima Centauri (4.2 light years away) according to their time frame.

Blame Lorentz, not meh

If we could go back to pg 2, and think about the finger snapping example again, I had a question about it.


If the guy A was instantly accelerated to the speed of light, we're saying time for him, reletive to guy B would slow down/or speed up (whatever) and he would be getting fewer/more snaps during the time he was at the speed of light.

Now, here is where I'm getting hung up:

Guy B would be standing still, but from the point of view of Guy A, Guy B would have just suddenly taken off at the speed of light.

Even tho Guy B isn't moving, would time for him seem to speed up/slow down (whatever) in relation to Guy A?

With that said, wouldn't they still count the same number of snaps when they both returned standing next to each other?

There is a pretty decent explanation of the "Twin pseudo-paradox" here
. Should help explain the time dilation effect, from both observers.

Originally posted by Frosty
And yes it is possible to travel twice the speed of light, again according to Einstein.

I'd like to see that. Where does he say it?

Twice the speed of light? I don't think so - You become infinitly massive at c (speed of light), so it would be impossible to move after that.

Google is your friend: en.wikipedia.org...

I still don't understand how the twin pseudo-paradox theories accounts for any threshold(though I am more interested in math than physics). It explains a good deal about two bodies in motion toward, though I think the point is lost when the article attempts to state that the taveler in the train sees the door close before the light exits the doorway. I am correct in interpreting it that way?

Okay, let's try this.

T=t(sqrt(1-(v^2)/(c^2)))

Where T is the true time, and t is the time it appears to take from the stationary observer, and v is of course the velocity.

Up until v=c the equation makes sense. At v=c, though, all hell breaks loose. And, after that, time has to be imaginary in order for it to work.

Time isn't imaginary.