In 1610, the Italian astronomer Galileo Galilei pointed a small telescope at Jupiter and saw four small objects circling it — becoming the first human being in history to look at the night sky and see, with his own eyes, that the Earth was not the center of everything

On the first night, 7 January 1610, Galileo recorded what he was seeing in his observation notebook with the careful, slightly bemused understatement of a researcher who knew he was looking at something interesting but did not yet know what. He wrote that he had seen “three small but very bright” stars arranged along a […]