The number of people in the world engaged in this search for catastrophic impactors totals one or two dozen. How long into the future are you willing to protect Homo sapiens on Earth? Before you answer that question, take a detour to Arizona's Meteor Crater during your next vacation.

Part of me thinks that I've been called by the universe, to get all sort of spiritual about it. Like, I've had no actual say in the matter. The universe found me.

Some claim evolution is just a theory. As if it were merely an opinion. The theory of evolution, like the theory of gravity, is a scientific fact. Evolution really happened. Accepting our kinship with all life on Earth is not only solid science. In my view, it’s also a soaring spiritual experience.

When we see animals doing remarkable things, how do we know if we're simply seeing tricks or signs of real intelligence? Are talented animals just obeying commands, or do they have some kind of deeper understanding? One of the biggest challenges for animal researchers is to come up with tests that can distinguish between the two.

Scientific inquiry shouldn't stop just because a reasonable explanation has apparently been found.

When you're a hammer (as the saying goes), all your problems look like nails. If you're a meteorite expert pondering the sudden extinction of boatloads of species, you'll want to say an impact did it. If you're an igneous petrologist, volcanoes did it. If you're into spaceborne bioclouds, an interstellar virus did it. If you're a hypernova expert, gamma rays did it.

There are no wild, seedless watermelons. There's no wild cows... You list all the fruit, and all the vegetables, and ask yourself, is there a wild counterpart to this? If there is, it's not as large, it's not as sweet, it's not as juicy, and it has way more seeds in it. We have systematically genetically modified all the foods, the vegetables and animals that we have eaten ever since we cultivated them. It's called artificial selection.