If you could return a specific Time and place. ....

[Dinosaur]

Am sure Brigadoon would come up on a HER search? :face-approve:

[kevin wooldridge]

Possibly a bit of a digression and definitely on the fringe ( got to meet BAJR's expectations ) but has there ever been any archaeological evidence for time travellers

Applying logical reasoning to the question, surely the single most compelling suggestion for the existence of time travel is actually the lack of evidence i.e time travel alters the space/time continuum and in doing so 'wipes' evidence of contrasting parallels or non-temporal existences. This is the basis of the Novikov self-consistency conjecture ..... I challenge anyone to slip that into an archaeological report!!

[BAJR]

Who was it said no Dr Who talk in the Site Hut? LOL!

If I can work the following into a conversation today however, I will do it!

basis of the Novikov self-consistency conjecture

:face-approve:

Why are you brainier than me! not fair.. you hear!

I just wanted to know what they wiped their arses with in the Iron Age

[P Prentice]

yea something's come out of a black hole

[Jack]

aye tis the singlemost interestin bit of our history to me but bugger all to be certain of

Me three. Its where everything started to go wrong.

[Gaj]

Dounreay Nuclear Research Establishment, May 1958, at the turning on of the Dounreay Materials Testing Reactor. Just to see how nervous everyone looked before pushing the 'on button'. Must have been exciting times.

[Illuminated]

[quote=Wax]Possibly a bit of a digression and definitely on the fringe ( got to meet BAJR's expectations ) but has there ever been any archaeological evidence for time travellers QUOTE]

Out of place artefacts are pretty common - things that just shouldn't be in certain securely dated layers. They are always explained away through it being more likely that there was some inexplicable but unprovable soil or water movement, animal action or other bizarre contamination rather than them being evidence for time travel. Jury's out for me though
There's quite a good book by Michael Cremo (Forbidden Archaeology) which looks at the phenomenon and makes some good points on the amount of evidence that is discarded as it doesn't fit current models, he then goes on to be a bit too Von Dannikin though...

[kevin wooldridge]

Dounreay Nuclear Research Establishment, May 1958, at the turning on of the Dounreay Materials Testing Reactor. Just to see how nervous everyone looked before pushing the 'on button'. Must have been exciting times.

I know an archaeologist whose father designed one of the installations at Dounreay. I guess if she time-travelled with Gaj it would probably be to say 'Hi Dad !!'.....

[kevin wooldridge]

There's quite a good book by Michael Cremo (Forbidden Archaeology) which looks at the phenomenon and makes some good points on the amount of evidence that is discarded as it doesn't fit current models, he then goes on to be a bit too Von Dannikin though...

I guess he doesn't hold with the Novikov self-consistency conjecture then.....

[Jack]

Yeah evidence of time travel............depends on the nature of time/reality.

Last I heard physicists currently claim that traveling into the future is possible, but not into the past.

But based on the fact that the basic laws of the universe are up for a major re-jig (speed of light, universal constant not being constant, quantum world vs string theory) I'd wait and see on that one.

The problem (obviously) stems from information sent into the past will alter the conditions that created the information, hence changing the information. Thus you get a spiraling feed-back system like noise feedback at a gig.
I suspect that sending information/energy into the past would also break the (current) law of conservation of energy.

However, as with the speed of light (many things do travel faster than it) many theoretical particles are thought to travel back in time. If information could be attached to these particles you've got a working telephone to the past or a device that destroys the universe.

But..........to understand the ins and outs of possible time travel you need to understand time.

Its fairly easy to slow down (your own) seconds, traveling into the future is actually (according to current theory) easy. All you need is a spaceship that can travel very fast (close to the speed of light). I think the maths works out that if you travel to Alpha centuri (I think its a light year away) at close to the speed of light, then come back, it takes you just over two years..........but when you get back 50 years have passed on earth. Hence you've traveled into your own future without causing any nasty paradox.

Butif you can move space time in one direction and travel close to the speed of light in the other, your relative speed can be faster than light. Can't remember why but some claim that this can be used to send information into the past. Problem is you need something like a spinning black hole to spin space-time.

The big interesting thing (to me) is that if time-travel into the past is possible sometime in the future, it is possible in all time - you just have to nick a device. But of course people claim that if this was so we'd be aware of these travelers.
Kevin is correct though (in one theory of time travel) that some (including Asimov and S hawking I think) claim that there wouldn't be any evidence as everyone (including the traveler) will only be aware of their current time (having no other frame of reference)............makes me think where did the previous information from the previous time-line go; physicists get upset if information is destroyed.

I like to think of time as an infinite number of tree-like webs of paths of possibles. A single person in time is only aware of one path which seems linear (birth to death). But an observer free of time would see the web of possibles and could travel to any point in any web. This would of course alter the paths of several (or hundreds) people plodding on their linear paths.........but as they are not aware of their own futures (the paths they went along in the travelers past) nothing will have changed for them and they will continue merrily along their own linear time-paths but into a completely different future.

So thats ok, no paradox's there.........and interestingly creates a universe (or multiverse) of parallel worlds - isn't this predicted in string theory?

Ah but.....you cry, what if the traveler goes back in time and kills their own ancestor or even them self? Surely thats a paradox? The travelers present is changed by what he doe sin the past.

No, its not. The traveler is free-of time (otherwise he/she couldn't travel back in it) and not plodding along their own linear time-path. All that does is send some (or hundreds) of people along a time-path where the traveler isn't born.

Ah but what if the traveler goes back in time and kills a rival from their own present, surely that would create a paradox. Simple answer is, they can't.
If the traveler tries all that will happen is he/she goes back into the past...kills the rival (sending people along a new time path). If the traveler then returns to his own 'present' (although the term doesn't really apply), nothing will have changed as he/she has returned to the time-path where the rival wasn't killed.

The traveler would be better off traveling to the parallel time-path where his rival wasn't born if he/she wanted to feel smug and satisfied.