When I shop for fruit & melons I like to hold a grape next to a cantaloupe & think of Earth next to Jupiter. Then I eat Earth.

Research in education has shown that we remember field trips long into adulthood. I remember visiting the post office in second grade and looking at the sorting machine. I have vivid memories of that, when I don't even remember the name of the teacher who took me.

When Kennedy said, 'Let's go to the moon,' we didn't yet have a vehicle that wouldn't kill you on launch. He said we'll land a man on the moon in eight years and bring him back. That was an audacious goal to put forth in front of the American people.

If our solar system is not unusual, then there are so many planets in the universe that, for example, they outnumber the sum of all sounds and words ever uttered by every human who has ever lived. To declare that Earth must be the only planet with life in the universe would be inexcusably bigheaded of us.

Essentially every scientist, when posed with the question, "If you want to get science knowledge from Mars, do you want to send a geologist or do you want to send a robot?" Well, the real answer is, you can send 100 robots for the price of sending one geologist, so let's send 100 robots to 100 different locations, and then we would all benefit. So that's the answer you would get. And I agree with that answer.

The tenacity of life is mind-boggling. We keep finding it where no one thought it could be.

Science is like an inoculation against charlatans who would have you believe whatever it is they tell you.