Galileo Galilei

"The square of the period of any planet is proportional to the cube of the mean distance from the sun."

"He who will not learn from history is doomed to repeat it."

"Ideas are clean. They soar in the serene supernal air only by themselves."

"The hardest thing to see is what is in front of your eyes."

"I would say that the claim to truth of any theoretical construct can be verified only through experimentation."

"Eppur si muove - and yet it moves."

"The book of the universe cannot be read until we have learned the language and become familiar with the characters in which it is written."

"There is perhaps no greater impediment to the advancement of knowledge than the ambiguity of words."

"The laws of nature are but the mathematical thoughts of God."

"It is the nature of the strong to protect the weak, not to devour them."

"All bodies are colored, but not all colors are bodies."

"A single hair from a man's head might be thousands of times thicker than the width of an invisible little thing."

"Two truths cannot contradict one another."

"My brain is so constructed that I can only marvel."

"The mistake is common to make the vessel too small."

"Life is a journey; the destination is merely the end of thought."

"To command nature, we must obey her."

"The starry messenger speaks to those with ears to hear."

"Hope is the pillar that holds the sky from falling."

"Man's intellect is the nearest thing to divinity."

"Unhappy is the land that is in need of heroes."

"The eyes are blind when the mind is made up."

"Art and science are not enemies, but lovers."

"A man of science must be like a child, full of wonder and humility."

"Truth emerges more readily from error than from confusion."

"The heavens call to us; shall we not listen?"

"In the pursuit of knowledge, each day is a new beginning."

"He who would move the world must first move himself."

"The universe is a grand book written in mathematical symbols."

"Courage is not the absence of fear, but the triumph over it."