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What did Galileo Galilei discover about the Milky Way?
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Galileo
Galileo, oil painting by Justus Sustermans, c. 1637, in the Uffizi Gallery, Florence.
Using his telescope, Galileo Galilei discovered that the Milky Way is composed of countless individual stars. This observation was one of several significant findings he published in his 1610 work, The Sidereal Messenger.12