Americans Discover Time Travel

[new.vogue.nightmare]

No this is all wrong, all wrong. Time travel pfft I mean look at this for example.

researchers noticed some spinning gray fog in the sky over the pole on January 27 which they believed to be just ordinary sandstorm.

Ordinary sandstorms ay.. ...in antarctica.

Oh yeh because sandstorms are ordnary down there aren't they.

Apparently Indio is one of those people who can't recognize a joke when he sees it.

And yeah, Antactica is a giant desert, and indeed there is sand in some parts of it. And without much to stop the wind (except of course in the various mountain ranges), any sand would be blown around, thus making snadstorms very possible. Of course whether they actually do happen I wouldn't know for certain, as I haven't read up on Antarctica much.

[kroner]

Oh, now you've put me on the spot to explain special relativity... Ok, let's see if I can do this...
The speed of light is constant in all reference frames. This is the most importnat point.
Consider the following situation: You are in a very fast box car going at speed v, while I am standing next to the train watching.

Alright, so the first point is time dialation. A flaslight shines some light from the cieling of the train car straight down. To you, the light goes at the speed of light c and reaches the floor in h/c time where h is the height of the car.
Now to me, the light also goes at the speed of light c, but the light goes a different distance. While its going down, the car has also moved forward a distance of v*t. By the pythagorian theorem, the distance i see it go is not h, but sqr(h^2 + (v*t)^2). So if the distnce per time was the same but the distance traveled is different, the time for the same event has to be different. The time I experience must be longer.
While the for you the event takes t = h/c, for me, t = sqr(h^2 + (v*t)^2)/c. solve for t to get t = (h/c)*(1/sqr(1- (v/c)^2)). in other words, time goes faster for you by a factor of γ = 1/sqr(1- (v/c)^2).

Now comes the concept of there being no definition of simultaneous events. You shine two flashlights from the middle of the car towards each end. to you, both beams travel the same distance d and hit the ends of the car in the same amount of time t = d/c, but to me, the back end of the car comes up to meet the one light beam so that it only has to travel a distance of d - v*t1 in time t1 = d/(c + v), and the front end of the car moves away from the light and so it has to travel distance d + v*t2 in time t2 = d/(c - v). now obviously if the events started at the same time but took different amounts of time to complete, they didn't finish at the same time. to me the difference in time between the events at distance 2d apart is 2d*v/(c^2-v^2), even though to you they were simultaneous. from this we see that simultaneous events at different locations are not simultaneous from other reference frames.

I hope with these two principals, it becomes a bit more clear how relativity works and the speed of light can be constant in all reference frames. There is also length contraction and mass dialation but I won't get into that.

[new.vogue.nightmare]

Yeah. Length contraction and mass dilation are just...fuggin' weird.

[kroner]

There are a lot of websites that explain special relativity much better than I can and have pretty pictures that make it easier to understand. If you want to get a good understanding of how it all works, it's not too hard to find a good explanation online.

To properly explain mass dialation, the concept of rest energy and relativistic momentum need to be introduced and that's a pain.

[new.vogue.nightmare]

A pity my high school physics education is fading away so quickly. I used to understand it perfectly. Erm, well at least as perfectly as an average non physicist possibly could anyway o.o;;;;;

[Meh]

That helps. I forgot alot of those pieces.

[Spectrus_Wolfus]

but even by einstein's theory of moving away from an object at faster the the speed of light realistically you wern't travelling through time you where relitively travelling through time to a fixed point. they explain it well in the movie young einstein when he say's imagine you move away from a clock at the speed of light. the clock to you will look like it has stopped but in reality it's still moving it's just the lght coming from the clock which is what you can see of it appears to be frozen as the light you can see is the same since you are travelling at the same speed as it.and light having mass and inertia(sp?) is hopefully going to be proven correct so that laser launch system's and solar sail's. the use of laser's to launch space craft has been theorised but as yet we can't make a laser with enough power to test the theory yet. and as for solar sail's what esactly would be light enough to be moved by light but strong enough to carry passenger's hehe

[Indio no.9]

aparantly Indio doesn't get a joke

aparantly neither does meh

Your evading the issue.

An insult (hhmmmm an insult or a joke, let me think)is not the way to accept new knowledge.

I am wrong lots of times.

Learn to suck it up.

Is light effected by gravity?

Its so sad how americans will never apreciate English humour.[/quote]

[Meh]

*bows to Indio the most wise*

[west]

British humour? Bring it on.

I love Doug Adams, Monty Python, and the rest. I know British humour when I hear it, and I know what's funny.

Doesn't include Indio

[new.vogue.nightmare]

Maybe he meant British crack-baby humor? *shrug*

[kroner]

but even by einstein's theory of moving away from an object at faster the the speed of light realistically you wern't travelling through time you where relitively travelling through time to a fixed point. they explain it well in the movie young einstein when he say's imagine you move away from a clock at the speed of light. the clock to you will look like it has stopped but in reality it's still moving it's just the lght coming from the clock which is what you can see of it appears to be frozen as the light you can see is the same since you are travelling at the same speed as it.and light having mass and inertia(sp?) is hopefully going to be proven correct so that laser launch system's and solar sail's. the use of laser's to launch space craft has been theorised but as yet we can't make a laser with enough power to test the theory yet. and as for solar sail's what esactly would be light enough to be moved by light but strong enough to carry passenger's hehe

No, the clock would actually not be moving, not just because of the light, but because time for you would be going by infinitely fast compared to the clock. Of course you would be frozen from the clocks point of view, but it works because of the lack of consistent simultanity at different places in different frames. If you were to come back to the clock at the speed of light (compared to it) you would find it at exactly the same time that you left it.

and it's been proven for a long time that light has momentum.

[Sho]

I know. . . Let's discuss general relativity now!

[kroner]

ok, you start.

[Queen Ehlana]

Okay, I didn't read this entire thread, and I don't want to discuss relativity... BUT I can say that if time travel into the past is possible, it's a lot more complicated than some think because if you want to go back to 1968, you'll have to go to an entirely different place in the universe. The universe is moving at a great speed, so you'd have to calculate all the way back to the place at which that place on earth would be in the universe at that instant and compare it to where you are now as a factor. Not only that, but I'm wondering what would happen to the particles at which you arrive.

I honestly don't believe in backward time travel, but if it is proven possible, I have an open mind.