Galileo Galilei discovered Callisto, the fourth moon of Jupiter.
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Galileo discovered the first three satellites of Jupiter.
The Catholic Church forces Galileo Galilei to renounce his heliocentric world view.
The last signal from the Pioneer 10 space probe was received.
American astronomer Edward Emerson Barnard discovered Jupiter's fifth moon.
Saturn, Jupiter, and Mars came into alignment. Medieval scholars believed this phenomenon brought forth the Black Death.
