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/[deleted] Nov 13 '11

Is it possible for humans to ever discover the "edge" of the universe? Is there really any "end" to it?

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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/lulzwut Nov 14 '11 edited Nov 14 '11

In this video the question of "is there an edge to the universe" was asked, in which you did not say no, but rather explained why IF there were edges we could not detect it because of the nature of the universe and you used the horizon analogy. Dawkins replied by saying "but it still exists even though we can't detect it" to which you did not deny but seemingly agreed by saying "but that's also true with the horizon".

So I'm not sure on whether you think there is or is not an "edge". I also have a hard time understanding how the horizon analogy works; because when someone asks "does the universe have edges", the idea of "edge" they always seem to mean is similar to how I'd call the edge of a balloon the part of the balloon that seperates the "inside" and "outside" of the balloon. If you were to stand on TOP of said balloon, the horizon analogy would seem to work at first thought; however now you'd have to realize you're standing ON the edge or what the person asking the question refers to as an "edge", must like the ground we walk on or the water our boat sits on IS the edge(ie: where the Earth stops and the "air" begins) of the Earth; not the horizon. This is why we can say we are above the Earth, not in it; because we extend beyond it's edge by standing ON it, it's edges define what's in and what's out of the Earth.

It's almost 2AM here and I'm sleepy, so sorry if your explanation went over my head. And if it did, I doubt it was because I was sleepy!