Time travel.
- Thread starter Aaron
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Pete Pachota
Member
We've had a lof of conversation avout this in our physics class, so I will have to throw my 2 cents in:
There are two 'models' of possible time travel:
1. The 'Fixed universe' model (like in Harry Potter) means that any time travel caused events in our past have already happened and we can witness the changes the time travelers made. What speaks against this is the so called spectator paradox - If time travel was invented in the future, people would like to go to the past to witness the history changing events, such as the death of Christ. Supposedly, this never happened, at least in our universe.
2. The 'Alternate universe' model (like in Back to the future or Butterfly effect). Seems more likely than the other one.
Why? Explain.
True, even if you were traveling at the speed of light, any other light or ship traveling at the speed of light would be observed as traveling at the speed of light, regardless of its direction. Another thing is that Einstein claimed that it's impossible to ACCELERATE matter up to the speed of light (because you would need infinite energy to do that, as the mass of matter grows up to infinity upon approaching that speed). There is a possibility for a particle to travel at (photons) or beyond that speed, like the hypothetic Tachyon particles.
Another thing which is interesting when it comes to speed of light travel is the Warp drive from Star Trek, which was given some semi-scientific background. The idea is based on the concept that you could contract the space in front of the ship and expand the space behind it, so you could practically travel beyond the light speed without actually reaching it. Even though it's supposedly based on some physical fallacies, it's worth checking out if you're interested in that kind of stuff.
To get back to the topic, the only way I personally see both time and deep space travel possible is to use or create wormholes somehow, the spacetime is curved, so you can find a shortcut and go along it.
There are two 'models' of possible time travel:
1. The 'Fixed universe' model (like in Harry Potter) means that any time travel caused events in our past have already happened and we can witness the changes the time travelers made. What speaks against this is the so called spectator paradox - If time travel was invented in the future, people would like to go to the past to witness the history changing events, such as the death of Christ. Supposedly, this never happened, at least in our universe.
2. The 'Alternate universe' model (like in Back to the future or Butterfly effect). Seems more likely than the other one.
seankane said:
Why? Explain.
AaronBransdon. said:
True, even if you were traveling at the speed of light, any other light or ship traveling at the speed of light would be observed as traveling at the speed of light, regardless of its direction. Another thing is that Einstein claimed that it's impossible to ACCELERATE matter up to the speed of light (because you would need infinite energy to do that, as the mass of matter grows up to infinity upon approaching that speed). There is a possibility for a particle to travel at (photons) or beyond that speed, like the hypothetic Tachyon particles.
Another thing which is interesting when it comes to speed of light travel is the Warp drive from Star Trek, which was given some semi-scientific background. The idea is based on the concept that you could contract the space in front of the ship and expand the space behind it, so you could practically travel beyond the light speed without actually reaching it. Even though it's supposedly based on some physical fallacies, it's worth checking out if you're interested in that kind of stuff.
To get back to the topic, the only way I personally see both time and deep space travel possible is to use or create wormholes somehow, the spacetime is curved, so you can find a shortcut and go along it.
Pete Pachota said:
sorry, i don't remember the theory behind it, i saw it a couple years ago, but the guy explaining it was one of the world's leading theoretical physicist's, so i believe it.
i'm not saying its definitely true since pretty much everything involved with time travel is just theory, but i know it sounded logical when i heard it, i just can't remember why. when i've got more time i'll find the show and rewatch it.
Pete Pachota
Member
http://en.wikipedia.org/wiki/SpacetimeEncarmine said:
russian serjey
Member
akll this time travel is all bull shit it cant happen..PERIOD
edit:also this is my 1111 post
edit:also this is my 1111 post
Snow Patrol
Member
yeah i saw the one they made using lasers etc, sounds cool.seankane said:
its a crazy thing to think on
team_punishment
dargersaurus rex
i see time travel to the past messing everything up. if you go to the past no matter what you do it will effect the future somehow. if by doing that resulted in you not building a time travel device or you not being born wouldnt you just disapear or something?
Chaseme37
Member
books to read on this:
einsteins dreams
and then some other one I can't remember haha
basically einsteins theory of time is that it is relative. like so:
a man is sitting on a train, facing north, staring at a clock and a mirror. the train is set to travel south. while the train is stopped at the station, he would see the clock ticking normally, and any movement he made would be immediately reflected by the mirror. the train then speeds up to half the speed of light. the clock would take 2 seconds for each second the hand moves, and any movement he made, it would take twice as long for his reflection to make them. why? because the light from the mirror and the clock is traveling towards his eyes, but he's traveling away from it (he's facing north and he's traveling south) so in essence, he has "slowed down" time. now, the train speeds up to the speed of light. the clock would stop ticking, and any movement he made would not be reflected by the mirror, the reflection would stay frozen. the light cannot catch up with his eyes, because he is traveling away from it at the exact same speed it is going. he has effectively stopped time. so to everyone else in the world, everything would be going normal, but this man would be frozen in time. that is why time is RELATIVE. oh and if the train abruptly stopped, the clock would instantly zoom to the current time, and all the movements he made would instantly play out in front of him faster than he could percieve, and everything would be back to normal. crazy huh?
einsteins dreams
and then some other one I can't remember haha
basically einsteins theory of time is that it is relative. like so:
a man is sitting on a train, facing north, staring at a clock and a mirror. the train is set to travel south. while the train is stopped at the station, he would see the clock ticking normally, and any movement he made would be immediately reflected by the mirror. the train then speeds up to half the speed of light. the clock would take 2 seconds for each second the hand moves, and any movement he made, it would take twice as long for his reflection to make them. why? because the light from the mirror and the clock is traveling towards his eyes, but he's traveling away from it (he's facing north and he's traveling south) so in essence, he has "slowed down" time. now, the train speeds up to the speed of light. the clock would stop ticking, and any movement he made would not be reflected by the mirror, the reflection would stay frozen. the light cannot catch up with his eyes, because he is traveling away from it at the exact same speed it is going. he has effectively stopped time. so to everyone else in the world, everything would be going normal, but this man would be frozen in time. that is why time is RELATIVE. oh and if the train abruptly stopped, the clock would instantly zoom to the current time, and all the movements he made would instantly play out in front of him faster than he could percieve, and everything would be back to normal. crazy huh?
team_punishment
dargersaurus rex
i think i got what you just said, crazy stuff
Pete Pachota
Member
Chaseme37 said:
No. A traveller going at the speed of light in a vessel would percept anything that's moving with him normally, e.g. the mirror, the clock. It's just that the time outside the vessel would run ABNORMALLY FAST. Your reasoning is based on old Newtonian physics + the idea that the speed of light is the maximum speed. The basic claim of the special relativity theory is that the speed of light is the same in any inertial system, regardless of it's motion, speed of the light source etc.
Joe Hilditch
Member
my head hurts
nickdonatelli
Member
if any can build a time traveling device it would be apple
Chaseme37
Member
^^^^ k well, that's not my theory, it's einstein's, so if you don't like it, take it up with him haha. it still makes sense though because the light is still being reflected off the mirror and clock and everything and if he's traveling away from it than it can't catch him. that makes sense dude