WhenIWasYourAge: It took a week to learn whether your photos came out okay.

Something bad happened on both Mars with its dried-up watercourses and Venus with its runaway greenhouse effect. Could something bad happen on Earth too? Our species currently turns row upon row of environmental knobs, without much regard to long-term consequences.

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

I think the material that inspires artists is the fabric of the soul of civilization.

Intelligent life can't be all that common because it's really rare on Earth and especially since we define ourselves to be intelligent. But in the eyes of an alien coming here who has the technology to make it here, they might observe us and conclude that there's no sign of intelligent life on Earth.

The people that first climbed Mt. Everest weren't scientists, right, they were adventurers. If you're an adventurer, you want to go yourself. It's different than a scientist, who is simply wanting to learn.

I think science has a better story to tell than anyone else has been able to tell and that's because it's based on the rigorous winnowing that science and scientists are always doing in order to find out what's really happening. I think it's really good to encourage generally our ability to tell stories and that's a great skill that we come by naturally, so I'm excited about that.