What If the Earth Was a Moon of Jupiter?

There are 79 known moons of Jupiter. What if we move Earth into its orbit too?

How would jupiter’s super strong gravity affect our lives? What would our skies look like? How long could you survive on a freezing planet that’s full of volcanoes?

When you run into an old friend in the last place you’d expect to see them, you figure it’s a small world. When you find out that the planet Jupiter could hold over 1,300 Earths, you realize, it’s a tiny world.

Picture this: if Earth was the size of a grape, Jupiter would be the size of a basketball. We’ve got one moon. Jupiter has 79, and counting.

So yeah, Jupiter’s a big [beep] deal. And orbiting it would be a dream for all you Instagrammers out there; but in this case, a picture doesn’t make it last longer, when every day is a struggle for survival.

It’s a really, really cold morning, and that’s because Jupiter is 778 million km (484 million miles) from the Sun. That means 25 times less luminosity, and 25 times less heat than we currently enjoy at Earth’s present location. Fortunately, the Sun is super bright, so we’d still get daylight; but if we were to compare Earth to Jupiter’s closest moon, IO, days would last about 40 hours long.

Of course, that wouldn’t really matter, because if you were born on the Earth-moon of Jupiter, you’d probably grow up not knowing sunlight. The gravitational pull from Jupiter’s other nearby moons, and the planet itself, would generate extreme tidal forces.

These would actually generate a lot of heat on our planet-moon, but internally. This explains why Jupiter’s atmosphere is about -145º Celsius, while its core temperature is hotter than the surface of the Sun! So yeah, that’s how you end up in a world where, if the cold doesn’t get you, then maybe the daily earthquake, tsunami, or volcanic eruption will.

Well, either that or you’ll just be cooked to death. Jupiter’s magnetic field is 10 times stronger than Earth’s, meaning that it emits a million times more radiation. So, if you really want to make life on Jupiter’s Earth-moon work, living underground is your best bet.

Even still, could you survive a year on Jupiter? One year on Earth, is one month on Jupiter, since it takes Jupiter 12 years to go around the Sun.

Every month on Jupiter, the planet gets hit by about 12 to 60 comets or asteroids. Large or small, their impacts are much more consequential. Since Jupiter’s gravitational pull accelerates these objects to a collision speed of about 216,000 km/h (134,000 mph), at the minimum.

If Earth became one of Jupiter’s moons, we’re now in the line of fire. As a much, much smaller planet we’re less likely to be able to absorb those kind of impacts. You’ve done your best underground, but there’s nowhere left to go when a sizeable astroid obliterates your home.

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