Possibility of Life in the Known Universe

Do not use Einstein as a way of making this sound like it is on a par with the general and special theories.There are physicists that have done some speculating about time travel. It is not clear that it is impossible yet though most take it to be. It is clear that it isn't easy and travel to the past isn't like the effects of travel to the future by time dilation.

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one would think so.. but its not the way it works or is thought to work.

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BS. It damned sure is the way it is thought to work. This speculation is not based on Einstein's theories except in that the vocabulary of those theories is incorporated into the speculative flights of fancy. Didn't you suggest some of Hawking's books? Try rereading them- carefully.------------------
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I'm not sure what you mean to ask/suggest, but I'll try to clarify.Light travels the same speed, in a vacuum, no matter what the perspective. And that speed is finite, and not all that fast considering the size of the universe. There is simply no way to get anywhere further than 2 light-years distant in 2 years, because that is how long it takes light itself to make the trip. That two years on the light-beam may seem like 40,000 to someone hanging on Earth, but that isn't the claim being made.------------------
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but with any speculation there most be good reason for. I mean we aren't even sure if going forward like that works! what makes one think that the other is impossable?

Time travel to the futureLet's try to clarify this again.Time dilation is a measured phenomenon. IF you can get up to 90% and more of light speed it becomes significant.You can travel 100's or 1000's of light years in a handful of your years if you travel near enough to the speed of light. That is a very well established fact.Time travel the other way is a much murkier subject and the very best efforts of physicists to develop suggestions always get into recipies like:
First you make a black hole ....

"You can travel 100's or 1000's of light years in a handful of your years if you travel near enough to the speed of light. That is a very well established fact."Actually, no. You are mixing up time and distance. Theoretically, you can travel hundreds or thousands of years into the future of a stationary place, by traveling with a speed near enough light speed relative to that stationary place, and it will cost you only a few of your years. But you said "100's or 1000's of light years", which are distances. And a distance of a thousand light years takes light a thousand years to traverse. So it will take a traveler at least that long, on his own clock, to do the same.Sorry for barging in like that.Cheers.

Let's send a spaceship to centauri, 4 light years away. Assume hi tech acceleration to just under light speed (.999 c) in 6 months and similar deceleation at the end.
The time on earth for this trip will be the year of acceleration and decleration plus t (t being somewhat more than 4 yrs depending on how near light speed the ship reaches)from Feynmann's lectures on physics, vol 1"That is, when the clock in the space ship records 1 second elapsed as seen by the man on the ship, it shows 1 / sqrt(1- v**2/c**2 ) second to the man outside."Note that in the above as v becomes large the time seen by an observer on earth becomes large while the 1 second elapses on the ship.
at .999 of c the denominator becomes .0447
and t on earth is about 4 / .999 = 4.004 years
t2 is then 4.04 * .0447 = .1789 yearsThe ship will cover the 4 light years. The observer on it will experience only a couple of months (aside from the acceleration phases).If the ships speed becomes great enough the effect becomes more and more pronounced. For an extreme case read Poul Andersons "Tau Zero".Also note that time for a photon does not pass. On a photon's clock no time passes from Andromeda to here.

NosyNed,My apologies, I believe you are right. You were not mixing up things, I was. It is on the stationary clock that it takes thousands of years for someone to travel thousands of light years at near light speed. My mistake.Cheers.