Galileo Galilei

It is a beautiful and admirable thing to know that the moon is not smooth and polished, but rough and uneven, just like the surface of the earth.

The motion of the Earth is a fact, not a theory.

I consider the discovery of the Medicean stars (Jupiter's moons) to be the most important of all my observations.

The universe is an immense, eternal, and infinite machine, which is always in motion.

It is not in the power of any created being to make a new truth.

The sun, with all the planets that revolve around it, and depend on it, can still ripen a bunch of grapes as if it had nothing else in the universe to do.

It is a great pity that there are so few who understand the true nature of things.

I do not think it is necessary to believe that the same God who gave us our senses, reason, and intellect intended for us to abandon their use.

The more I study, the more I am convinced that the world is governed by laws that are not arbitrary.

It is not the function of the Church to tell us how the heavens go, but how to go to heaven.

I have discovered in the heavens many things that contradict the teachings of Aristotle.

The Earth is not the center of the universe.

The truth of a proposition is not determined by the number of people who believe it.

It is a beautiful thing to observe the moon, not as a perfect sphere, but as a body with mountains and valleys, just like our Earth.

The purpose of science is not to open the door to infinite wisdom, but to set a limit to infinite error.

I have observed the phases of Venus, which proves that it orbits the Sun, not the Earth.

The Earth is a planet, just like the other planets, and it revolves around the Sun.

The senses, when they are well-directed, are the best guides to truth.

I cannot believe that the same God who has endowed us with sense, reason, and intellect has intended us to forgo their use.

The universe is a vast and complex machine, and we are only just beginning to understand its workings.