Jupiter has the strongest magnetic field of any planet in the Solar System. Its field is roughly 20 times stronger than Earth’s near the cloud tops and creates the largest planetary magnetosphere known.
The field is generated by an internal dynamo involving electrically conducting metallic hydrogen deep inside Jupiter. Under immense pressure, hydrogen behaves like a metal and can carry electrical currents. Jupiter’s rapid rotation helps organize those currents into a powerful magnetic field tilted by about 10 degrees relative to the planet’s rotation axis.
Jupiter’s magnetosphere is not merely a stronger version of Earth’s. It is heavily supplied with plasma from Io, whose volcanic eruptions release sulfur dioxide that becomes ionized and trapped in Jupiter’s magnetic environment. The magnetosphere stretches millions of kilometres and produces intense radiation belts, strong radio emissions, and spectacular auroras. Saturn, Uranus, and Neptune also have magnetic fields, but none matches Jupiter’s overall strength or scale. Earth’s field is weaker, though it remains crucial for shielding our atmosphere and surface from much of the solar wind.