Like a snowplow in overdrive, a supernova shockwave might sweep away any gas clouds in its path.

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.

I've known from long ago that the universe was calling me. If you were one of those annoying adults that said, 'Oh, what are you gonna be when you grow up?' I would say, 'Astrophysicist .' And then they'd walk away real quickly.

One of the most significant events in our distant past is still perhaps the greatest mystery: the origins of life itself.

I try to show the public that chemistry, biology, physics, astrophysics is life. It is not some separate subject that you have to be pulled into a corner to be taught about.

Follow the evidence wherever it leads, and question everything.

I simply go with what works. And what works is the healthy skepticism embodied in the scientific method. Believe me, if the Bible had ever been shown to be a rich source of scientific answers and enlightenment, we would be mining it daily for cosmic discovery.