Jupiter's Core | Universe Today

Written by Fraser Cain

Jupiter is a gas giant. It's made of about 90% hydrogen and 10% helium, with trace amounts of other elements. Since it's made almost entirely of hydrogen and helium, astronomers aren't exactly sure if Jupiter has a solid core.

If you could fly to Jupiter and descend down into the planet, you would experience increasing temperatures and pressures. If you could reach the core of Jupiter, you would discover a dense core with a mixture of heavy elements about twice the radius of Earth. In fact, it's thought that there could be 12 to 45 times the mass of Earth down at the core; but compressed down to this small size of only twice the size of Earth. Astronomers determined this through gravitational studies of Jupiter. They're not sure if it's actually a rocky core, or some kind of liquid core. But it's also possible that there's no solid core at all, and can be explained by dense hydrogen. Jupiter's core accounts for 3-15% of the mass of Jupiter.

Surrounding Jupiter's potentially solid core is a layer of dense metallic hydrogen. This is hydrogen compressed down to the point that it exhibits metallic properties. This metallic layer accounts for 78% of the radius of Jupiter. This metallic layer only starts with the temperatures inside Jupiter reach 10,000 kelvin, as well as intense pressure. Since the hydrogen acts like a metal, its movement within Jupiter creates the planet's powerful magnetic field.

The temperature of Jupiter's core is thought to be 24,000 kelvin. That's 23,726° C, or 42,740° F. But don't worry about Jupiter turning into a star. The core of the Sun is 25.7 million kelvin. That's the kind of temperature it takes to reach nuclear fusion in the core.

We've written several articles about planetary cores for Universe Today. Here's an article about the Earth's core, and here's an article about the core of Mercury.

If you'd like more info on Jupiter, check out NASA's World Book on Jupiter, and here's a link to NASA's Solar System Exploration Guide.

We've also recorded an episode of Astronomy Cast all about Jupiter. Listen here, Episode 56: Jupiter.

Filed under: Astronomy