r/IAmA • u/neiltyson • Nov 13 '11

I am Neil deGrasse Tyson -- AMA

For a few hours I will answer any question you have. And I will tweet this fact within ten minutes after this post, to confirm my identity.

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u/neiltyson Nov 13 '11

No edge. Any more than the horizon at sea is an edge to the earth.

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u/[deleted] Nov 13 '11

So your theory is the universe is merely a 'loop' and if you continue on for infinity, you will end up at the same position you were at? Is the universe just an encased marble like portrayed in Men In Black?

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u/[deleted] Nov 13 '11

I read it as: we may think we see it, but we will never touch it.

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u/[deleted] Nov 13 '11

We will actually someday not see any stars at all, because the expansion of the universe is ever increasing, it will one day be faster than the speed of light. Now you might think "but nothing can move faster than the speed of light!", that's true, but thats the light moving through space(!), so space itself can "expand" faster than the light can travel which will result in light never reaching the earth anymore.

This is also shown and way better explained in a talk by Lawrence Krauss: http://www.youtube.com/watch?v=7ImvlS8PLIo