Home / Authors / Galileo Galilei

Galileo Galilei

Galileo Galilei Quotes

Physicist

Galileo Galilei, an Italian physicist, astronomer, mathematician, and philosopher, is considered the father of modern science. He was born on February 15, 1564, and died on January 8, 1642. Galileo made significant contributions to the fields of physics, astronomy, mathematics, and philosophy. He discovered the four moons of Jupiter through his telescope, supporting Copernicus' heliocentric model, and proposed the law of free fall and other scientific theories.

Filter quotes by topic

All Science Ifs Men Mathematics Earth Knows Reason Universe Written Believe Language Moving Holy Mean Opinion Sun Thinking Book Eye Firsts

Famous Galileo Galilei Quotes

“The sun, with all those planets revolving around it and dependent on it, can still ripen a bunch of grapes as if it had nothing else in the universe to do.”

“I have been judged vehemently suspect of heresy, that is, of having held and believed that the sun in the centre of the universe and immoveable, and that the earth is not at the center of same, and that it does move. Wishing however, to remove from the minds of your Eminences and all faithful Christians this vehement suspicion reasonably conceived against me, I abjure with a sincere heart and unfeigned faith, I curse and detest the said errors and heresies, and generally all and every error, heresy, and sect contrary to the Holy Catholic Church. (Quoted in Shea and Artigas 194)”

“E pur si muove. "Albeit It does move". (That's what Galileo purportedly muttered after torturers forced him to recant his theory that the earth orbits the sun.)”

Doe Earth Moving Sun Theory Orbit

Author:Galileo Galilei

“I therefore concluded, and decided unhesitatingly, that there are three stars in the heavens moving about Jupiter, as Venus and Mercury about the Sun; which at length was established as clear as daylight by numerous other observations.”

Moving Science Three Heaven Stars Sun Clear Decided Observation Length Daylight Referring Telescopes Venus Mercury Jupiter Pioneering

Author:Galileo Galilei

“In my studies of astronomy and philosophy I hold this opinion about the universe, that the Sun remains fixed in the centre of the circle of heavenly bodies, without changing its place; and the Earth, turning upon itself, moves round the Sun.”

Philosophy Body Earth Moving Universe Opinion Sun Study Remains Rounds Astronomy Circles Fixed Heavenly Centre Cosmology Heavenly Bodies

Author:Galileo Galilei

“But what exceeds all wonders, I have discovered four new planets and observed their proper and particular motions, different among themselves and from the motions of all the other stars; and these new planets move about another very large star [Jupiter] like Venus and Mercury, and perchance the other known planets, move about the Sun. As soon as this tract, which I shall send to all the philosophers and mathematicians as an announcement, is finished, I shall send a copy to the Most Serene Grand Duke, together with an excellent spyglass, so that he can verify all these truths.”

“Spots are on the surface of the solar body where they are produced and also dissolved, some in shorter and others in longer periods. They are carried around the Sun; an important occurrence in itself.”

Important Body Science Universe Sun Mystery Periods Surface Spots

Author:Galileo Galilei

“When the moon is ninety degrees away from the sun it sees but half the earth illuminated (the western half). For the other (the eastern half) is enveloped in night. Hence the moon itself is illuminated less brightly from the earth, and as a result its secondary light appears fainter to us.”

Light Earth Science Night Results Half Sun Moon Degrees Western Eastern Ninety

Author:Galileo Galilei

“Take note, theologians, that in your desire to make matters of faith out of propositions relating to the fixity of sun and earth you run the risk of eventually having to condemn as heretics those who would declare the earth to stand still and the sun to change position-eventually, I say, at such a time as it might be physically or logically proved that the earth moves and the sun stands still.”

Stills Matter Might Running Earth Moving Science Desire Religion Sun Risk Position Notes Propositions Theologian Heretic

Book:Dialogue Concerning the Two Chief World Systems, Ptolemaic and Copernican, Second Revised Edition

Source: Dialogue Concerning the Two Chief World Systems, Ptolemaic and Copernican, Second Revised Edition