I remain fearless of airplanes after 9/11. But during a trip to Los Angeles on a Boeing 767, I couldn't keep my mind from drifting: What's the largest piece of this airplane that could crash into the World Trade Center, explode out the other side, and survive intact? The landing gear? My computer battery? My belt buckle? My wedding ring?

There is no true understanding of Biology without Chemistry. And there's no true understanding of Chemistry without Physics.

We can trace the elements. They were forged in the centers of high-mass stars that went unstable at the ends of their lives, they exploded, scattered their enriched contents across the galaxy, sprinkled into gas clouds that then collapsed and formed stars and planets and life.

It is in the best interests of civilization and our economy and our nation to understand what objective truths are as revealed by the methods and tools of science.

We're talking about a being whose very existence challenges our own sense of priority in the universe.

When I reach to the edge of the universe, I do so knowing that along some paths of cosmic discovery, there are times when, at least for now, one must be content to love the questions themselves.

Let us not fool ourselves into thinking we went to the Moon because we are pioneers, or discoverers, or adventurers. We went to the Moon because it was the militaristically expedient thing to do.