Io Has Tides Like Earth, Only They're Made Of Rock
The gravitational pull of Jupiter and its other moons on the moon Io is so great that it creates ground tides that cause solid rock to regularly rise and fall by hundreds of feet.
Like Our Moon, But Completely Different
The most volcanic known object in our solar system, Io is a moon pockmarked by active volcanoes and lakes of lava. It's roughly the size of our own moon, but its surface is nothing like it: it's constantly pulled to and fro by the gravity of Jupiter's other moons and the gas giant itself. These forces result in solid ground tides, which heave the ground up and down depending on where Io is in its orbit. The moon's "tidal bulge" can shift in height by up to 330 feet (100 meters).
Most of us only know about tides as something that happens in water. And it's true: the types of forces that create the waves in our oceans are the same ones that cause the ground to violently shift on Io. Just imagine what would happen to our oceans, much less the ground we stand on, if we were as close to Jupiter—and surrounded by as many moons—as Io is. Then be happy we're not!
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