Jupiter is a gas giant, which means it has no solid surface. Instead, its atmosphere gradually transitions into a liquid mantle and then a core. The planet has a rocky center that’s about 11 times the size of Earth but only 2-3 percent as massive.

The internal heat of Jupiter was first identified in 1979 when Pioneer 10 flew past Jupiter on its way to Saturn. Scientists found that the temperature at Jupiter’s cloud tops was appropriately higher than expected for an object with such low surface gravity and distance from the Sun (the amount of energy received).

They also noticed that the temperature increased with depth, which could be attributed to two things: 1) convection – hot material rising from below and cooler material sinking back down again; 2) radioactivity – decay of elements like uranium or thorium inside the planet’s core.

Since then, there have been several missions to study Jupiter’s interior including Galileo (1995-2003), New Horizons (2006), Juno (2011-), Cassini (2004-2017), Voyager 1 & 2 (1977-2012), Pioneer 10 & 11 (1973-2003), Ulysses (1990-2009) and spacecraft from other countries such as Japan and Germany.

Last modified: October 8, 2022