First  Prev  1  2  3  4  5  6  7  8  9  10  11  12  13  14  15  16  17  Next  Last
Time Travel...Your Thoughts
17204 cr points
Send Message: Send PM GB Post
Offline
Posted 1/5/07
http://video.google.com/videoplay?docid=-5896048467372201322

I remember watching this on T.V. It has some good info. I liked it!
10834 cr points
Send Message: Send PM GB Post
25 / M
Offline
Posted 1/5/07
Possible? Probably.

Time travel in theory:

Some theories, most notably special and general relativity, suggest that suitable geometries of spacetime, or specific types of motion in space, may allow time travel into the past and future if these geometries or motions are possible.[3] In technical papers physicists generally avoid the commonplace language of "moving" or "traveling" through time ('movement' normally refers only to a change in spatial position as the time coordinate is varied), and instead discuss the possibility of closed timelike curves, which are worldlines that form closed loops in spacetime. There are known to be solutions to the equations of general relativity that describe spacetimes which contain closed timelike curves, but the physical plausibility of these solutions is uncertain.

Although the possibility of traveling to the future by moving at relativistic velocities is taken for granted by physicists, many in the scientific community believe that backwards time travel is highly unlikely. Any theory which would allow time travel would require that issues of causality be resolved. What if one were to go back in time and kill one's own grandfather (see grandfather paradox)? Additionally, Stephen Hawking once suggested that the absence of tourists from the future constitutes an argument against the existence of time travel—a variant of the Fermi paradox, with time travelers instead of alien visitors (but Hawking noted elsewhere that time travel may only be possible in a region of spacetime that is warped in the right way, and that if we can't create such a region until the future, then time travelers would not be able to travel back before that date, so 'This picture would explain why we haven't been over run by tourists from the future.'[4]) However, the theory of general relativity does suggest scientific grounds for thinking backwards time travel could be possible in certain unusual scenarios, although arguments from semiclassical gravity suggest that when quantum effects are incorporated into general relativity, these loopholes may be closed. These semiclassical arguments led Hawking to formulate the chronology protection conjecture, suggesting that the fundamental laws of nature prevent time travel, but physicists cannot come to a definite judgment on the issue without a theory of quantum gravity to join quantum mechanics and general relativity into a completely unified theory.


Using wormholes:

Wormholes are a type of warped spacetime which are also permitted by the Einstein field equations of general relativity, although it would be impossible to travel through a wormhole unless it was what is known as a traversable wormhole.

A proposed time-travel machine using a traversable wormhole would (hypothetically) work something like this. A wormhole is created somehow. One end of the wormhole is accelerated to nearly the speed of light, perhaps with an advanced spaceship, and then brought back to the point of origin. Due to time dilation, the accelerated end of the wormhole has now aged less than the stationary end, as seen by an external observer. However, time connects differently through the wormhole than outside it, so that synchronized clocks at either end of the wormhole will always remain synchronized as seen by an observer passing through the wormhole, no matter how the two ends move around. This means that an observer entering the accelerated end would exit the stationary end when the stationary end was the same age that the accelerated end had been at the moment before entry; for example, if prior to entering the wormhole the observer noted that a clock at the accelerated end read a date of 2005 while a clock at the stationary end read 2010, then the observer would exit the stationary end when its clock also read 2005, a trip backwards in time as seen by other observers outside. One significant limitation of such a time machine is that it is only possible to go as far back in time as the initial creation of the machine[9]; in essence, it is more of a path through time than it is a device that itself moves through time, and it would not allow the technology itself to be moved backwards in time. This could provide an alternative explanation for Hawking's observation: a time machine will be built someday, but has not yet been built, so the tourists from the future cannot reach this far back in time.

According to current theories on the nature of wormholes, construction of a traversable wormhole would require the existence of a substance known as "exotic matter" with negative energy. Many physicists believe this may actually be possible due to the Casimir effect in quantum physics.[10] Although early calculations suggested a very large amount of negative energy would be required, later calculations showed that the amount of negative energy can be made arbitrarily small.[11]

In 1993, Matt Visser argued that the two mouths of a wormhole with such an induced clock difference could not be brought together without inducing quantum field and gravitational effects that would either make the wormhole collapse or the two mouths repel each other. [12] Because of this, the two mouths could not be brought close enough for causality violation to take place. However, in a 1997 paper, Visser hypothesized that a complex "Roman ring" (named after Tom Roman) configuration of an N number of wormholes arranged in a symmetric polygon could still act as a time machine, although he concludes that this is more likely than not a flaw in classical quantum gravity theory rather than proof that causality violation is possible. [13]



Source for both - http://en.wikipedia.org/wiki/Time_travel
13014 cr points
Send Message: Send PM GB Post
74 / F / in the club
Offline
Posted 1/5/07
I was about to ask you where you 'copy and paste' that. Good thing you put the source or else, i'd say you're a genius.
3237 cr points
Send Message: Send PM GB Post
25 / M / ** Besides Hell,...
Offline
Posted 1/5/07
.....woa!.....that's one hell of an attempt for assasination.....by the way i'm one of Bush's CIA agent.....i've got my eye on you...nya-ha-ha-ha....

i like the way you comment on things.....you're one hell of a guy....*salute*...

could be....but i big to differ...i have this other theory...."Travelling through time will create another timeline. You might create a time where you kill Hitler and the world exists without him in one timeline but in yours you might or might not exist...another present could exist.. 'cos history do change then"......

but then everything is possible.......

if this would be possible....one thing i'd like to change....that i was never born...dead to the world and forgotten.......wish that was possible....*sigh*
17204 cr points
Send Message: Send PM GB Post
Offline
Posted 1/5/07
If you go back in time, would you be able to kill Hitler? Because in the past, everything you see is present, relatively, so you know the future. So was World War 2 destined by fate?
3237 cr points
Send Message: Send PM GB Post
25 / M / ** Besides Hell,...
Offline
Posted 1/5/07
ffate?that's another story...could be....but then you can never tell time.....d'ya think?
17204 cr points
Send Message: Send PM GB Post
Offline
Posted 1/5/07
Well lets see if you killed your grandfather, your dad/mom would have never been born. So you wouldn't have been born to go back in time to do that. So bascically, you probably never existed.
1546 cr points
Send Message: Send PM GB Post
24 / Martian / Estonia
Offline
Posted 1/5/07
well if it is a possibility or if it is actually possible to travel through time then i would think that itd actually have to be very simple, for f it requierd heavy machinery and a huge powersource then it would be pointless to use it, wouldnt it? i mean you could go to the middle ages but you couldnt return because the machine lacks fuel.
But didint Einstein already prove that it would be impossible..?..?..?
3237 cr points
Send Message: Send PM GB Post
25 / M / ** Besides Hell,...
Offline
Posted 1/5/07
^^...could be....or i could exist as another person.....maybe..let's see...ahmm...the one who invented time machine....Nya-ha-ha-ha....ain't that nice....eh?
46535 cr points
Send Message: Send PM GB Post
Offline
Posted 1/5/07
ooh you beat Eros with the wikipedia article Azezeil, he's going to be pissed (he has a problem )
6212 cr points
Send Message: Send PM GB Post
27 / M / US
Offline
Posted 1/5/07
Muahahah I'm going to go an a rampage and eat a bunch of babies.

But, actually Mauz I would not go to wiki for time travel, but the philosophical encyclopedias!

http://www.iep.utm.edu/t/timetrav.htm
http://plato.stanford.edu/entries/time-travel-phys/
http://plato.stanford.edu/entries/time-machine/
A logical discussion for good measure: http://www.sfu.ca/philosophy/swartz/time_travel1.htm
1471 cr points
Send Message: Send PM GB Post
F / phil
Offline
Posted 1/5/07
As of now I think that’s not possible. And even if it were possible I wouldn’t change a thing. Past is past you can’t change what had happen in the past

“you can’t be born again although you can change”
Fruit basket
6212 cr points
Send Message: Send PM GB Post
27 / M / US
Offline
Posted 1/5/07
Oh hell yes I would want to go the the future, if possible, and assuming its better then now, which it should be considering progress.

Paradoxes should unsettle us for two reasons. Either the world is in a knot, or our question is bad and our understanding of the world is poor. Lets hope its the latter, which is much more likely after all. So, I don't think the grandfather question gives enough information. One would have to add on to it and give it context to come up with a good, useful, and meaningful answer.
843 cr points
Send Message: Send PM GB Post
26 / M / Denmark
Offline
Posted 1/5/07
go back in time, and safe my head from the drop
6572 cr points
Send Message: Send PM GB Post
25 / M / United States
Offline
Posted 1/5/07
time travel isnt possible, for instance say u want to go back in time and change something, the reason y its not possible is because in the future you would have already done it therefore you wouldnt be going back in time in the first place
First  Prev  1  2  3  4  5  6  7  8  9  10  11  12  13  14  15  16  17  Next  Last
You must be logged in to post.