Question on time travel with aliens.

[Dreamhope11]

If time travel is possible how come humans in the future havent come back to tell us?? if you get me. Or maybe aliens are us in the future, no hair due to global warming, grey skin to reflect the suns heat. Maybe they are going back in time to warn us to stop carbon emmisions, to stop us ruining our future.

[saxonharp]

If time travel is possible how come humans in the future havent come back to tell us?? if you get me. Or maybe aliens are us in the future, no hair due to global warming, grey skin to reflect the suns heat. Maybe they are going back in time to warn us to stop carbon emmisions, to stop us ruining our future. That's kind of the great paradox of time travel, isn't it? If "aliens" are as you say, "us form the future" and they are here to tell us to change what we did to make them that way, and we do, then what becomes of them? Do they cease to exist because we changed the environment that created them? Or do they exist in a parallel universe? If that is the case, then no matter what we do, it won't affect them so what's the point? Of course, the space time continuum may have been changed any number of times, but because we're a part if it, we'd never know the difference. For instance, how do we know that in some alternate reality, the Germans weren't able to mass produce the jet fighters they had perfected near the end of WWII? Or that when we set off the first atomic bomb at Los Alomos, that it DIDN'T start a chain reaction that burned up the entire atmosphere of the planet? Physical time travel just has too many "wierdities" to be useful.

[Ruhe1986]

I personally don't think time travel is possible. I think Time doesn't exist, not in the way we imagine it. It's just a way humans (and our brains) measure moments and movement within space. We live in a constant state of present with the things we have done in what we call "the past" and things we haven't done in what we call "the future".

[Chrno666]

If time travel is possible how come humans in the future havent come back to tell us?? if you get me. Or maybe aliens are us in the future, no hair due to global warming, grey skin to reflect the suns heat. Maybe they are going back in time to warn us to stop carbon emmisions, to stop us ruining our future. time rule you can't change something in the past and live to tell about it it's as simple as that.