“If we ruin the earth, there is no place else to go.”

Nature is unsentimental. Death is built in.

We are star stuff which has taken its destiny into its own hands.

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

Not all birds can fly. What separates the flyers from the walkers is the ability to take off.

Nature is always more subtle, more intricate, more elegant than what we are able to imagine.

When we look up at night and view the stars, everything we see is shinning because of distant nuclear fusion.

Imagination will often carry us to worlds that never were, but without it we go nowhere.

The nitrogen in our DNA, the calcium in our teeth, the iron in our blood, the carbon in our apple pies were made in the interiors of collapsing stars. We are made of starstuff.

If you wish to make an apple pie from scratch, you must first invent the universe.

The Earth is a very small stage in a vast cosmic arena.

Except in pure mathematics, nothing is known for certain (although much is certainly false).

Every kid starts out as a natural-born scientist, and then we beat it out of them. A few trickle through the system with their wonder and enthusiasm for science intact.

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

I’ve always thought an agnostic is an atheist without the courage of his convictions.

Perhaps the depth of love can be calibrated by the number of different selves that are actively involved in a given relationship.

What an astonishing thing a book is.

Man is on earth as in an egg.

To a wise and good man the whole earth is his fatherland.

We’re all put on this earth to walk in His image, the Master.

We shall have our manhood. We shall have it or the earth will be leveled by our attempts to gain it.

For famous men have the whole earth as their memorial.

Nobody on this earth is perfect. Everybody has their flaws; everybody has their dark secrets and vices.

This planet is a wonderful place, but a vulnerable place.

Heaven on Earth is a choice you must make, not a place you must find.