When your reasons for believing something are justified ad hoc, you are left susceptible to further discoveries undermining the rationale for that belief.

If we're going to affect policy, or affect attitudes, for me, the adults have always been the target population.

When I needed to overcome the low expectations of others or the bias that would be expressed in one circumstance or another, I'd keep on keeping on. And I climb over the obstacle, go around it, dig under it, fly over it. That's what kept me going. Otherwise I would have never been an astrophysicist.

A conspiracy theorist is a person who tacitly admits that they have insufficient data to prove their points. A conspiracy is a battle cry of a person with insufficient data.

So what is true for life itself is no less true for the universe: knowing where you came from is no less important than knowing where you are going.

To believe in a universe as young as 6 or 7,000 years old is to extinguish the light from most of the galaxy.

Some claim evolution is just a theory. As if it were merely an opinion. The theory of evolution, like the theory of gravity, is a scientific fact. Evolution really happened. Accepting our kinship with all life on Earth is not only solid science. In my view, it’s also a soaring spiritual experience.