== His telescope and astronomical discoveries ==
[[File:Galileo-telescopes.jpg|right|200px|thumb|Early-1900's photograph of Galileo's telescopes]]
In June or July of 1609, Galileo heard about the telescope, which had been invented in [[Netherlands|Holland]]. Without knowing the technical details of the construction of the device, he was able to create one for himself. Over time he continued to upgrade it. He found mountains on the Moon, viewed the phases of [[Venus]], and discovered four satellites around [[Jupiter]] as well as locating [[sunspots]].