The greatest explorer of recent decades is not even human.

I can tell you that in my modern life I enjoy language. I enjoy words, their meaning, what they sound like to the ear, what they sound like to the listener. I strive to write the perfect sentence in all that I do, and when I write [the] perfect sentence I know it. If I had a second life I'd be a librettist for Broadway musicals.

We account for all the matter and energy that we're familiar with, measure up how much gravity it should have, it's one-sixth of the gravity that's actually operating on the universe. We call that dark matter. It really should be called dark gravity. We don't know what that is.

Where there's water on Earth, you find life as we know it. So if you find water somewhere else, it becomes a remarkable draw to look closer to see if life of any kind is there, even if it's bacterial, which would be extraordinary for the field of biology.

The problem, often not discovered until late in life, is that when you look for things like love, meaning, motivation, it implies they are sitting behind a tree or under a rock. The most successful people recognize, that in life they create their own love, they manufacture their own meaning, they generate their own motivation. For me, I am driven by two main philosophies, know more today about the world than I knew yesterday. And along the way, lessen the suffering of others. You'd be surprised how far that gets you.

You could do math early, but there are no brilliant 16-year-old novelists. They don't know the human condition yet.

But my vote for Venus's most peculiar feature is the presence of craters that are all relatively young and uniformly distributed over its surface. This innocuous-sounding feature implicates a single planetwide catastrophe that reset the cratering clock... turning Venus's entire surface into the American automotive dream-a totally paved planet.