| From: Yoda Oz | 4/02/99
13:44:57 |
| Subject: Time Travel | post id:
306 |
| Just regarding einstein's
grandfather paradox, how would you manage to go back in time to kill you
grandfather anyway? I know that the further out into space travelling faster than the speed of light you go further back into time, but if you go around earth faster than the speed of light you wouldnt be going back in time because youre not going "out" into space. Am i correct??? | |
| From: steve | 4/02/99
13:50:12 |
| Subject: re: Time Travel | post id:
307 |
| I'm of the firm opinion that
travelling through time is not possible in a physical manner. That is, you
will never be able to get in a craft (of whatever description) and travel
through time (either forwards or backwards - and I know, we all travel
forward through time ;-) I think the only way this will be / is possible is using mystical techniques such as astral travel. By which I mean "out of body" experiences. Cheers Steve Baty | |
| From: Craigus | 4/02/99
13:55:56 |
| Subject: re: Time Travel | post id:
309 |
I think the crux of this matter is not the direction of travel, but the speed. As I understand it, it is travelling (theoretically) faster than the speed of light that induces negative temporal travel. Also, if you were a great distance away from the earth, and were looking back at it, you would be "seeing" backwards in time, due to the time taken for light from earth to reach you. As such, you could see your grandfather, but not kill him :-). | |
| From: Benn Hall | 4/02/99
14:00:33 |
| Subject: re: Time Travel | post id:
312 |
| On Karls show today he mentioned
particles that were thought to exist that traveled faster than light i.e.
went backward rather than forward. If these particles are moving backward,
where have they come from, the future? | |
| From: Craigus | 4/02/99
14:05:11 |
| Subject: re: Time Travel | post id:
314 |
| Benn, Very interesting. If they are travelling backwards in time, they must indeed have come from the future. That being the case, where/when were they created? Obviously not at the start of the Universe, they must have come from the End of the universe ;-) | |
| From: Madcat | 4/02/99
14:08:23 |
| Subject: re: Time Travel | post id:
315 |
| There is a definite way of
travelling forwards through time (in a way). From Einsteins Relativity, if
you accelerate to near light speeds, time will slow down for you, but not
for those who are not accelerating (inertial frames, etc). This is the
basis for the Twin Paradox. If one twin goes to Jupiter in a ship
accelerating at 1G, and then comes back, he would have aged a matter of
months, while the other has aged several decades. Backwards is harder, however, there may be a way to link two worm holes together to achieve a similar effect. | |
| From: James Richmond | 4/02/99
14:14:03 |
| Subject: re: Time Travel | post id:
317 |
| Forwards time travel is no
problem according to relativity. This is the basis of the famous "twins
paradox", which, when properly analysed, is not really a paradox at all.
Relativity says that if you jump into a spaceship on Earth, fly around at
near light speed for a while, then return, you'll have aged less than the
people who didn't come along for the ride. On the other hand, backwards time travel poses big problems for causality, that is, the idea that effects follow the events which caused them. If you could travel faster than the speed of light, then in some reference frames cause and effect would be reversed. Special relativity prevents material objects from ever getting to the speed of light, let alone exceeding it. However, general relativity may allow us to get around this restriction, for example, by using wormholes. I suspect that the universe won't allow this sort of thing and that therefore either we won't be able to construct traversible wormholes or we'll discover some new law of nature which prevents causality violation. | |
| From: Jeremy | 4/02/99
14:29:30 |
| Subject: re: Time Travel | post id:
326 |
| Lets have a bit of
fun. Look guysNgals. If time travel were possible and we eventually do it, then we would already know how to do it right? 'Cause some future lame brain is just bound to slip into our past, boast about it and hey-presto we find out that it's possible. BUT. If that's the way we find out, then who found out first? The wonderful thing about a paradox - a real one - is that it tells you when a theory is trash. BTW: the twins paradox is not really a paradox. | |
| From: James Richmond | 4/02/99
14:32:15 |
| Subject: re: Time Travel | post id:
330 |
| Maybe we live in a particularly
boring era, which no time travellers from the future can be bothered
visiting. After all, the whole of past and future history is a big place
(so to speak). Alternatively, maybe backwards time travel will be
underfunded in the future! | |
| From: Jeremy | 4/02/99
14:39:41 |
| Subject: re: Time Travel | post id:
334 |
| In answer to : "Maybe we live in
a particularly boring era, which no time travellers from the future can be
bothered visiting. After all, the whole of past and future history is a
big place " Since it is a "big place" there are Big chances that someone would get curious. We don't find ANY of our own history boring enough to ignore it. Heck - people on this list want to know what happened even before the big bang. That must be a pretty boring place! I'd be more impressed with someone concluding that we therefore have no future..... | |
| From: Ciaran H | 4/02/99
14:44:46 |
| Subject: re: Time Travel | post id:
339 |
| In reply to the wormhole
potential to time travel, my understanding of wormholes indicates that the
best you could hope for travelling through a wormhole is to travel
instantaeously since in a wormhole time travels in a direction
perpendicular to it's direction outside the wormhole. Try getting your noggin round that! Ciaran. | |
| From: mad-dog | 11/02/99
2:22:20 |
| Subject: re: Time Travel | post id:
790 |
| madcat - how can this be, time is
a form of measurement which humans have developed, i find it hard to
believe that by traveling the speed of light that you age less than
someone that isn't traveling at the speed of light. speed is a mesurement of distance over time, yet we define these values, and these figures are always related to the earth, which means the speed of light on another planet it different? or does this mean when you are traveling in your car say at 100km/hr that you have not aged as much as someone walking or standing still. What if alians are watching us and are laughing saying things like - look at them, they're only going at 1km/hr (while we think we're traveling at 100km/hr) | |
| From: James Richmond (Avatar) | 15/02/99
22:44:17 |
| Subject: re: Time Travel | post id:
1253 |
| Mad-dog, read the posts below on
time dilation. They should help clear things up a bit. The main point to make is that time and space are not separate entities, rather different aspects of one thing, spacetime. When two people travel at relative to one another, they each have their own separate perceptions of time and space. In a sense, part of one person's space becomes part of the other's time, and vice versa. | |