> I'm actually using a very inclusive sense of 'us' here, meaning any sort of life. Okay, fair enough, that's reasonable -- so once we detect any sort of extra

> I'm actually using a very inclusive sense of 'us' here, meaning any sort of life. Okay, fair enough, that's reasonable -- so once we detect any sort of extraterrestrial life, then we can forget about leaving the planet. After all, there's life everywhere, so our leaving Earth loses its significance. I think we'll colonize Mars for the adventure, or to satisfy our curiosity, not as a first step in colonizing the universe. The latter might be what we'll say, but it won't be the real reason.