When I arrived on the planet, there were only two billion. Wildlife was more abundant, we were less so; now the situation is reversed.

There's something missing about how we're informing the youngsters coming along about what matters in the world. We teach them the numbers and the letters, but we fail to communicate the importance of our connection to the living world.

Any astronaut can tell you you've got to do everything you can to learn about your life support system and then do everything you can to take care of it.

Humans have always wondered the big questions, "Who am I? Where have I come from? Where am I going?" It's part of human nature. It's perhaps the underpinnings of religion.

With knowing comes caring.

Ten percent of the big fish still remain. There are still some blue whales. There are still some krill in Antarctica. There are a few oysters in Chesapeake Bay. Half the coral reefs are still in pretty good shape, a jeweled belt around the middle of the planet. There's still time, but not a lot, to turn things around.

Evolution is not something to be feared. It's to be celebrated, embraced, and understood.