We know right where a bunch of aliens are: the bottom of the ocean. Incredibly, it's so hard to go there that it's considered a joke to suggest it, whereas with

We know right where a bunch of aliens are: the bottom of the ocean. Incredibly, it's so hard to go there that it's considered a joke to suggest it, whereas with space it seems if it weren't for the problem of the sheer distances involved, we could really do it and just go anywhere.