In science it often happens that scientists say, 'You know that's a really good argument; my position is mistaken,' and then they would actually change their minds and you never hear that old view from them again. They really do it. It doesn't happen as often as it should, because scientists are human and change is sometimes painful. But it happens every day. I cannot recall the last time something like that happened in politics or religion.

A stars rich in europium; of distant galaxies analyzed through the collective light of a hundred billion constituent stars. Astronomical spectroscopy is an almost magical technique. It amazes me still. Auguste Comte picked a particularly unfortunate example.

Our passion for learning ... is our tool for survival.

One of the greatest gifts adults can give - to their offspring and to their society - is to read to children.

Not explaining science seems to me perverse. When you're in love, you want to tell the world.

A book is proof that humans are capable of working magic.

There are no forbidden questions in science, no matters too sensitive or delicate to be probed, no sacred truths.