Jupiter

Jupiter is the fifth planet from the Sun, and the largest in the solar system, by far — more than twice as massive as the other planets combined.

Facts About Jupiter

Jupiter is the largest and oldest planet in our solar system.

If Jupiter was a hollow shell, 1,000 Earths could fit inside. But the "King of Planets" is no lumbering giant — Jupiter has the shortest day in the solar system, taking about 9.9 hours to spin around once on its axis.

Get the Facts

A view of Jupiter's Great Red Spot and colorful cloud bands of tan, brown, white, and orange as seen from the Juno spacecraft.

NASA’s Juno spacecraft imaged Jupiter’s Great Red Spot on Feb. 12, 2019.

Enhanced image by Kevin M. Gill (CC-BY) based on images provided courtesy of NASA/JPL-Caltech/SwRI/MSSS

Observing Jupiter’s Auroras, Juno Detected Callisto’s Elusive Footprint

Final missing signature from Jupiter’s four largest moons

Unlike Earth’s Moon and our planet’s northern lights, the massive, shimmering auroras above Jupiter’s poles carry signatures that the planet’s largest moons leave in the atmosphere. Before NASA’s Juno mission, three of Jupiter’s four largest moons, known as Galilean moons — Io, Europa, and Ganymede — were shown to produce these distinct auroral signatures. But Callisto, the most distant of the Galilean moons, remained a mystery.

An illustration shows Jupiter at the center of the image with its four Galilean moons extending toward the left — Io, Europa, Ganymede, and Callisto, their orbits traced by ever-increasing ellipses. On the other side of the image, another arc, in blue and entering from the right side of the image, shows the Juno spacecraft's orbit around Jupiter. Below that, in the lower right corner, an inset image diagrams auroras above Jupiter linked to each of the four moons, tracing bright arcs in green and orange.

Juno capturing the marks on Jupiter of all four Galilean moons. The auroras related to each are labeled Io, Eur (for Europa), Gan (for Ganymede), and Cal (for Callisto).

NASA/JPL-Caltech/SwRI/UVS team/MSSS/Gill/Jónsson/Perry/Hue/Rabia