On January 7, 1610, Galileo was the first person to train a telescope on Jupiter—and what he saw surprised him. Strung in a line beside the planet were three tiny stars, one to the left of the planet and two to the right. But when he observed the formation the next night, he saw that now all three were on the same side of Jupiter. Over the following week, he watched as the tiny stars (now joined by a fourth) changed their position relative to the planet while remaining beside it. By January 15, he had it figured out: he was observing four moons orbiting Jupiter.
Jupiter and the Galilean moons
Today in History
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Surfer s paradise
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30 years after Exxon Valdez
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A tale of almonds and bees
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Oud-West, Amsterdam, Netherlands
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Mother s Day
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A cutting-edge art gallery opens in Paris
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A star blows a bubble
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National Take a Hike Day
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Celebrating World Water Day
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A day of death and rebirth
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Get amped for Glastonbury
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The Giants Causeway, Northern Ireland
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Petrified Forest National Park
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Palouse farmland, Washington state
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Bidding summer adieu
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Arbor Day
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Al-Khazneh in Petra, Jordan
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Mount Hood, Oregon
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Portland celebrates its bounty
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In memory of those lost
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Hello, spring!
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Maloja, Switzerland
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Lionfish off the coast of Indonesia
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St. Paul Winter Carnival
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Endangered Species Day
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Brooklyn Bridge Park in Brooklyn, New York
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Ring of fire
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It’s not a pinecone, it’s a pangolin
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It s Teacher Appreciation Week
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Saint Dwynwen s Day