Prior to Civilization VI: Gathering Storm, the maximum possible Science from Galileo Galilei in most circumstances is 1250. However, with the addition of the Mountain Tunnel, it is possible to obtain 1500 Science.
Another Renaissance Era Great Scientist, Emilie Du Chatelet, provides three Eurekas from the Renaissance or Industrial Era. The three most expensive Industrial Era technologies are 930 Science each, so Emilie provides at most 1116 (3 * 930 * 0.4) Science. Therefore, Galileo Galilei is always a better choice if he can be activated with 5 adjacent Mountain tiles. The exceptions are when playing as the Chinese or the Babylonians and under the vanilla ruleset, in which cases you can gain at least 1395 (3 * 930 * 0.5) Science from Emilie Du Chatelet.
In any history of science, Galileo Galilei plays a key part; he is a – if not the – central figure in the Scientific Revolution. His works on physics, astronomy, and the scientific method still evoke debate. And his travails and tribulations at the hand of the Church remain a cautionary tale for scientists today. By the time he died, Galilei had become as famous (or infamous) as any person in Europe – even the popes that condemned him.
Born in 1564 in Pisa, the lad Galileo in 1583 embarked on the study of medicine at the University of Pisa, but left in 1585 due to financial difficulties. He turned to supporting himself with minor teaching positions, amusing himself by studying objects in motion, leading to the publication of 'The Little Balance.' That, in turn, gained him a teaching post at the University of Pisa, where his experiments with falling objects contradicted the Church-sanctioned Aristotelian theories of physics. Which would have been tolerated, except he published 'On Motion,' and his contract was not renewed. No matter. He quickly found a position at the University of Padua, where for 18 years he lectured in geometry and astronomy.
For Galileo, this newfound popularity and prosperity led him to pursue new interests – building telescopes and observing the heavens. In 1610, he began publishing his findings, arguing in favor of the heliocentric Copernican theory. The Church was incensed as his writings became ever more substantial, for in 1616 the Holy Inquisition had pronounced the Copernican theory heretical, and in July 1634 Galileo was convicted of heresy. In January 1642, the “father of modern science” died in Arcetri, still under papal arrest.