On this night in science
Galileo finds Jupiter's moons
January 7, 1610
On this night in 1610, Galileo looked at Jupiter through his telescope and saw three small stars lined up beside it. Night after night they moved, and soon he understood: they weren't stars at all, but moons going around Jupiter.
Why it mattered
It was the first time anyone had seen things circling a world other than the Earth. It helped show that not everything in the sky goes around us.
Wonder together
What do you think it would be like to see four moons in the sky at once?
There's an episode about this
Jupiter: A World Made of Sky
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