Is Time Travel Possible and What Are Its Implications?

[ben328i]

if hasn't already been said. which i think it might have
time travel to the future is possible.
you can not go backwards
you have to go faster than light to actually achieve time travel.
that is millions of millions miles and hour.
what have we hit recently ? maybe 2 grand maybe 4

 

[W3pcq]

we hit excess of 20k in space.

 

[W3pcq]

If you define time using a photon emitter, then how would you measure a reversal of time with the same device?
If no photons emit, then I suppose T=0. How can a negative amount of photons be emitted? I guess if the emitter stops emitting and begins to take in photons, then "time" has reversed?

Maybe if you could somehow absolutely eliminate all velocity and maximize gravity, then you could never age? Maybe that is what black hole is. In black whole T=0, maybe <0? There is a debate over wether or not time can exist without matter, if time can't exist without matter, then could matter exist without time. If time was slowed to zero would we cease to exist? If time could go from 0 to -n, would we have already been crushed out of existence by the time we reached t=0?

 

[basePARTICLE]

If you define time using a photon emitter, then how would you measure a reversal of time with the same device?If no photons emit, then I suppose T=0. How can a negative amount of photons be emitted? I guess if the emitter stops emitting and begins to take in photons, then "time" has reversed?

Maybe if you could somehow absolutely eliminate all velocity and maximize gravity, then you could never age? Maybe that is what black hole is. In black whole T=0, maybe <0? There is a debate over wether or not time can exist without matter, if time can't exist without matter, then could matter exist without time. If time was slowed to zero would we cease to exist? If time could go from 0 to -n, would we have already been crushed out of existence by the time we reached t=0?

As soon as someone says define time as XXX we usually encounter new physics, unless there is irreducible correspondence.

 

[Ian Davis]

The focus on whether time travel is possible seems to presume that the past continues to exist. I would be interested is strictly mathematical devices demonstrating that there was a mathematical theory that supported the notion that there was some past to go back to in the first place.

http://www.rochester.edu/news/show.php?id=2544
http://seattlepi.nwsource.com/local/292378_timeguy15.html
http://cs.astronomy.com/asycs/forums/p/29882/361586.aspx#361586

I've not seen the problem raised here that were one to go backwards in time, short of finding a very auspicious route that avoided the problem altogether, one would at the
moment in time when one ceased moving forward in time collide with that former self
that was still moving forward in time. If charges are reversed for matter moving backwards in time this would I suspect (feel free to contradict me -- I'm no expert) be a case of a very large quantity of matter meeting an equally large quantity of anti-matter. Not a good recipe for surviving long enough to declare that time travel works. Even circumventing this issue, one would create a nightmare in the book-keeping department where all sorts of physical properties are supposed to be preserved.

 

[oliverswanshu]

Hello everyone,
I am new to this forum and would greatly appreciate your expertise in answering (or attempting to) a few questions for me. I don't care if you focus on one or all of them, but any answers are appreciated! These are about time travel, with a focus on traveling BACK in time...

1. Will time travel ever be possible?
2. If so, how soon? Also, how far back would we be able to travel?
3. Would our bodies be able to survive time travel?
4. Would time travellers be able to communicate with other humans, or would they be on a separate plane of time/dimension?
5. Is it possible that spaceship sitings are time travel machines from the future?

Also, if anyone can answer #4 (at least in theory), I'd be grateful.

That simple statement of fact is the key to understanding why we cannot nor will not- ever- physically travel, either forward or backward, in time. We, the computer keyboard I am using, my house, the planet, all the planets in our solar system not to mention all the galaxies; in fact the universe and everything in it; only PHYSICALLY exists in the present- in the NOW. There is no future- physically now. We and the whole universe does not PHYSICALLY exist in ten minutes AT PRESENT. We can be confident that it will because it DID ten minutes ago.
And that's the point. Thats the simple truth of it all. Because we remember the past we therefore anticipate the future.
We (and everything) physically exist only in the NOW. The PRESENT. We and everything (and I mean everything) do not physically still exist ten minutes- one nano second ago. Nor do we physically exist at present, one minute from NOW.
Simple eh?