This influential, yet controversial idea requires that the mixture of species on Earth at any moment acts as a collective organism that continuously (yet unwittingly) tunes Earth's atmospheric composition and climate to promote the presence of life... But I'd bet there are some dead Martians and Venusians who advanced the same theory about their own planets a billion years ago.

When your reasons for believing something are justified ad hoc, you are left susceptible to further discoveries undermining the rationale for that belief.

And extracting one molecule's signature in spectral analysis from the rest of the signatures is hard work, sort of like picking out the sound of your toddler's voice in a roomful of screaming children during playtime. It's hard, but you can do it.

I bought it, I read it, and I heeded its advice. I remain unabducted.

It’s short-sighted to think ads won’t one day end up wherever humans are - even the moon.

Luckily, there are some rocks left over from our earliest days, asteroids formed during our solar system's birth. Occasionally, some of them drop in on Earth, and when they do, they're called meteorites.

If you're a scientist, and you have to have an answer, even in the absence of data, you're not going to be a good scientist.