The moon gravitates towards the earth and by the force of gravity is continually drawn off from a rectilinear motion and retained in its orbit.

The bad fortune of the good turns their faces up to heaven; the good fortune of the bad bows their heads down to the earth.

Gravity must be caused by an Agent acting constantly according to certain laws, but whether this Agent be material or immaterial I have left to the consideration of my readers.

Property is intended to serve life, and no matter how much we surround it with rights and respect, it has no personal being. It is part of the earth man walks on. It is not man.

The youth gets together his materials to build a bridge to the moon, or, perchance, a palace or temple on the earth, and, at length, the middle-aged man concludes to build a woodshed with them.

There are no black holes in the sense of regimes from which light can’t escape to infinity.

God grant that not only the love of liberty but a thorough knowledge of the rights of man may pervade all the nations of the earth, so that a philosopher may set his foot anywhere on its surface and say: ‚This is my country.‘

Evolution can go to hell as far as I am concerned. What a mistake we are. We have mortally wounded this sweet life-supporting planet – the only one in the whole Milky Way – with a century of transportation whoopee.

There could be shadow galaxies, shadow stars, and even shadow people.

The senses are of the earth, the reason stands apart from them in contemplation.

Fill the earth with your songs of gratitude.

Opinion has caused more trouble on this little earth than plagues or earthquakes.

Nothing is further than earth from heaven, and nothing is nearer than heaven to earth.

I can honestly say – and it’s a big surprise to me – that I have never had a dream about being on the moon.

It is clear to everyone that astronomy at all events compels the soul to look upwards, and draws it from the things of this world to the other.

The earth laughs in flowers.

All the evidence, experimental and even a little theoretical, seems to indicate that it is the energy content which is involved in gravitation, and therefore, since matter and antimatter both represent positive energies, gravitation makes no distinction.

The most remarkable discovery in all of astronomy is that the stars are made of atoms of the same kind as those on the earth.

I put up my thumb and it blotted out the planet Earth.

The earth is supported by the power of truth; it is the power of truth that makes the sun shine and the winds blow; indeed all things rest upon truth.

Science sent the Hubble telescope out into space, so it could capture light and the absence thereof, from the very beginning of time. And the telescope really did that. So now we know that there was once absolutely nothing, such a perfect nothing that there wasn’t even nothing or once.

The centre of the system of the world is immovable.

From the dust of the earth, from the common elementary fund, the Creator has made Homo sapiens. From the same material he has made every other creature, however noxious and insignificant to us. They are earth-born companions and our fellow mortals.

Life is tragic simply because the earth turns and the sun inexorably rises and sets, and one day, for each of us, the sun will go down for the last, last time.

On one of the SpaceX flights, we had a secret payload: a wheel of cheese. We flew to orbit and brought it back, so it was the world’s first ‚space cheese.‘ It was, in part, a tribute to Monty Python.

The earth belongs to the living, not to the dead.

Poets say science takes away from the beauty of the stars – mere globs of gas atoms. I, too, can see the stars on a desert night, and feel them. But do I see less or more?

Earth might one day soon resemble the planet Venus.

I thought the attractions of being an astronaut were actually, not so much the Moon, but flying in a completely new medium.

The smaller the planets are, they are, other things being equal, of so much the greater density; for so the powers of gravity on their several surfaces come nearer to equality. They are likewise, other things being equal, of the greater density, as they are nearer to the sun.

Modern science says: ‚The sun is the past, the earth is the present, the moon is the future.‘ From an incandescent mass we have originated, and into a frozen mass we shall turn. Merciless is the law of nature, and rapidly and irresistibly we are drawn to our doom.

No occupation is so delightful to me as the culture of the earth, and no culture comparable to that of the garden.

It is not easy to see how the more extreme forms of nationalism can long survive when men have seen the Earth in its true perspective as a single small globe against the stars.

Life is abundant, and life is beautiful. And it’s a good place that we’re all in, you know, on this earth, if we take care of it.

Long before the awakening of thought on earth, manifestations of cosmic energy must have been produced which have no parallel today.

Being a hero is about the shortest-lived profession on earth.

It’s been said that astronomy is a humbling and, I might add, a character-building experience.

Astronomy compels the soul to look upwards and leads us from this world to another.

And forget not that the earth delights to feel your bare feet and the winds long to play with your hair.

Heaven is long-enduring, and earth continues long. The reason why heaven and earth are able to endure and continue thus long is because they do not live of, or for, themselves.

We have one planet in our solar system that’s habitable, and that’s the Earth, and space travel can transform things back here for the better. First of all, by just having people go to space and look back on this fragile planet we live on. People have come back transformed and have done fantastic things.

One thing that I find very unmotivating is the kind of Plan B argument: when Earth gets destroyed, you want to be somewhere else. That doesn’t work for me. We have sent robotic probes now to every place in the solar system, and this is the best one.

The universe is a big place, perhaps the biggest.

For NASA, space is still a high priority.

Knowledge of the past and of the places of the earth is the ornament and food of the mind of man.

There are dark shadows on the earth, but its lights are stronger in the contrast.

Space is almost infinite. As a matter of fact, we think it is infinite.

Land on Mars, a round-trip ticket – half a million dollars. It can be done.

The pagan loves the earth in order to enjoy it and confine himself within it; the Christian in order to make it purer and draw from it the strength to escape from it.

I have explained the phenomena of the heavens and of our sea by the force of gravity, but I have not yet assigned a cause to gravity.

What springs from earth dissolves to earth again, and heaven-born things fly to their native seat.

You can’t blame gravity for falling in love.

This most beautiful system of the sun, planets, and comets, could only proceed from the counsel and dominion of an intelligent and powerful Being.

Even Hubble hasn’t found yet the end of this universe, and we don’t know that it has any end.

Let’s pray that the human race never escapes from Earth to spread its iniquity elsewhere.

I create stars.

Service to others is the rent you pay for your room here on earth.

The situation the Earth is in today has been created by unmindful production and unmindful consumption. We consume to forget our worries and our anxieties. Tranquilising ourselves with over-consumption is not the way.

Does wisdom perhaps appear on the earth as a raven which is inspired by the smell of carrion?

Atheism is so senseless. When I look at the solar system, I see the earth at the right distance from the sun to receive the proper amounts of heat and light. This did not happen by chance.

I can find in my undergraduate classes, bright students who do not know that the stars rise and set at night, or even that the Sun is a star.