How did Galileo Gailiei become a famous astronomer?
Though he did not invent the telescope, he was the first to grasp its potential in astronomy. He made two important discoveries with it, which laid his claim for fame. (1) on the night of January 7th 1610, he discovered the four largest moons of Jupiter which were revolving around it, and this was the observational proof needed to support Copernicus’ heliocentric Solar System. (Copernicus had published this view in 1543 in a book entitled “On the revolutions of the heavenly spheres”) Plainly if these moons went around Jupiter, everything did NOT go around the Earth as was claimed under the geocentric model advanced by Ptolemy in the 2nd Century AD (2) In September 1610 he trained his telescope on Venus and discovered that it exhibited a full range of phases jusr like The Moon, This was a further demonstration that everything went around the Sun, not the Earth. Galileo was however confused by Saturn as he sometimes saw the rings head on and sometimes not, and thought he was seeing somet
