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Moons Once Sparked a Revolution in Astronomy. Are They About to Do So Again?
New telescopes promise to reveal countless moons scattered across the galaxy
This story was originally published by The Quantum Cat, a regular newsletter covering space and science. Get it for free by signing up today!
Four centuries ago, the great Galileo spotted four pinpricks of light dancing around Jupiter. Night after night he watched them, observing how they clung close to the giant planet and followed it as it moved across the sky. Eventually he came to an stunning conclusion. These were not stars, as he had originally thought, but moons, the first ever to be seen beyond our own.
This raised a problem. At the time, most people believed that everything — the Sun, the Moon, the stars, and the planets — all revolved around the Earth. And that, in turn, put our planet, and by extension us, and the very centre of the cosmos. It was a good place to be, and nobody really wanted to be relegated to some lesser spot.
Yet here was Galileo contradicting the idea. The moons of Jupiter did not move around the Earth, he said, they moved around Jupiter. And if these moons could defy the Earth, then why couldn’t other objects? Things got even worse when Galileo started observing other things, like…
