## A train going with the speed of light

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Dunno
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### A train going with the speed of light

I've always wanted to play with this. Let's say that, hypothetically of course, a train with people inside manages to reach speed of light (or something very, very close to it, if you will). What do you think happens with those people inside? Think of something original, don't say "they explode" and similar. And assume that after it reaches that magical velocity, it continues its trip without slowing down (or speeding up ha, ha) so there is no force felt by everyone in. I guess the first and the most obvious question is: what do they see? Share your thoughts! (be careful though, or you might be the one exploding )
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powershot
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### Re: A train going with the speed of light

Dunno wrote: I've always wanted to play with this. Let's say that, hypothetically of course, a train with people inside manages to reach speed of light (or something very, very close to it, if you will). What do you think happens with those people inside? Think of something original, don't say "they explode" and similar. And assume that after it reaches that magical velocity, it continues its trip without slowing down (or speeding up ha, ha) so there is no force felt by everyone in. I guess the first and the most obvious question is: what do they see? Share your thoughts! (be careful though, or you might be the one exploding )
It matters how fast the train accelerated, but if didn't accelerate to fast, the people would be ok.

They would probably see things moving past them at the speed of light. Which would probably be a blur since they eye can't comprehend things as fast as light.

Scientifically : The train couldn't turn or it have to turn very, very slowly. And the emergency brakes wouldn't stop the train but it might hurt the people inside. Also, if the train hit a bump it could be a disaster.
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### Re: A train going with the speed of light

Dunno wrote:What do you think happens with those people inside?
I... don't know, they become electromagnetic radiation and we never hear of them again?
Last edited by ShikadiQueen on June 22nd, 2011, 8:19 pm, edited 1 time in total.
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Colouredbox
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### Re: A train going with the speed of light

Dunno wrote:What do you think happens with those people inside?
Propably just go through several dimensional gates (from Era of Magic) and reach the ultimate knowledge of the universe.
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Viliam
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### Re: A train going with the speed of light

Dunno wrote:What do you think happens with those people inside?
Nothing. The time stops for them.
Dunno wrote:what do they see?
They see whatever happens after the end of this universe.
Or something that happens before the end of universe that causes their train to slow down.
Or just emptiness... because they fly away from everyting else in the universe.

Anonymissimus
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### Re: A train going with the speed of light

Viliam wrote:
Dunno wrote:What do you think happens with those people inside?
Nothing. The time stops for them.
To give some more scientific answer, based on my little relativity knowledge.
For the passengers within their frame of reference (the train) nothing special happens. Time and space don't change. When they stop the journey the'll find that in the outer frame of reference time has passed much faster than for them, even tough time didn't slow down for them during their journey.
(It appears e.g. in films like "Close Encounters Of The Third Kind" where people who disappeared decades ago come back to earth but did not age.)

The train can't reach speed of light. The closer to light speed, the more energy is required to speed up even more towards light speed. It raises till infinity.
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Dunno
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### Re: A train going with the speed of light

Can they breathe...? And blood, does it circulate in their bodies...? I'm just new to this kind of physics and it just blows my mind
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powershot
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### Re: A train going with the speed of light

Well, Time would stop for people. The train track would have to go around the world because light can go around seven times a second. +The train would have to be connected to the track or (since the earth is a sphere) the train would fly off, and inevitably, the people would die.
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Crushmaster
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### Re: A train going with the speed of light

Wouldn't going at the speed of light turn you into pure energy?
EDIT: From extremely limited research (Google), the answer appears to be "Yes."
EDIT #2: Everything points to "Yes."

Besides the fact reaching it is impossible, yes...
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pauxlo
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### Re: A train going with the speed of light

From the view point of the photon (i.e. a piece of light), it arrives at the same time as it started. This would be a nice way of traveling. (From the outside, still some time passes, though.)

Of course, this is only possible for massless objects like a photon, all objects with mass would have to be accelerated slowly to reach a higher speed, and can never reach the speed of light, like Villiam said. If you run with a high speed, the time for you seems to run slower when seen from the outside (but the same is true in inverse - this seems paradoxical, but isn't).

Also, all light sent from objects which move relative to us shifts its frequency - to the red (i.e. lower frequencies) if we run away, to violet (i.e. higher frequencies) if we run towards this object.

I once calculated that if we drive with 10% light speed towards a red traffic light, it looks green

Insinuator
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### Re: A train going with the speed of light

Dunno wrote:Can they breathe...? And blood, does it circulate in their bodies...? I'm just new to this kind of physics and it just blows my mind
Yes. Nothing changes with respect to their bodies.

As Anonymissimus points out, according to our current understanding of physics, you CAN NOT reach the speed of light because the energy levels required to accelerate you to that speed are literally infinite. Because of that, the question is rather invalid. To make it more "realistic", you could imagine them as traveling at .97c.

powershot
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### Re: A train going with the speed of light

pauxlo wrote:
I once calculated that if we drive with 10% light speed towards a red traffic light, it looks green
You'd be going to fast to realize it's red before the traffic accident.
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### Re: A train going with the speed of light

powershot wrote:
Dunno wrote:They would probably see things moving past them at the speed of light. Which would probably be a blur since they eye can't comprehend things as fast as light.
Hypothetically, there wouldn't be any blur - you'd see the light from everything ahead of you condense into a disc in front of you, and the light from everything behind you condense into a disc behind you, everything in front dramatically red-shifted, everything behind dramatically blue-shifted, as you approached c.

Read Poul Anderson's Tau Zero for a very hard-sci-fi examination of how lightspeed effects might work.
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Frogger5
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### Re: A train going with the speed of light

Dunno wrote:Can they breathe...? And blood, does it circulate in their bodies...? I'm just new to this kind of physics and it just blows my mind
Only acceleration has an effect, not speed itself. They'd be able to move, eat, all of that, as long as the train is going at steady speed, it doesn't matter how fast its going. (of course, being faster than the speed of sound, Id imagine that talking might be a problem.) The other thing is you wouldn't be able to walk up the train, because then you'd be going faster than the speed of light, which is impossible.

Also, they'd travel forward in time. Something like; two weeks for them would be a decade outside.
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Mountain_King
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### Re: A train going with the speed of light

Ah, infamous time dilation. Crazy insane stuff let me tell you. It looks like all the important points have been settled already, so I'll just reiterate what everyone else has said. (Too bad too, I just finished my Physics class and we were talking about time dilation just three days ago.)
pauxlo wrote: I once calculated that if we drive with 10% light speed towards a red traffic light, it looks green
However, at 10% the speed of light, collision with a speck of dust is equal to 10 U.S. tons of TNT! (translation: they explode!)

If they reach the speed of light then they're pure energy already.

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