planetary-rings

Saturn's rings are the solar system's most famous structure, but they are far from unique. Uranus has 13 dark, narrow rings discovered by accident in 1977. Neptune has incomplete arcs instead of full circles. Jupiter has a faint ring made of dust blasted off its innermost moons by meteorite impacts. All four giant planets have rings — and they all work differently. Saturn's may be geologically young, which raises a question nobody has fully answered: where did they come from?

In 2017, NASA deliberately destroyed the Cassini spacecraft by plunging it into Saturn. Before it died, it made 22 passes through a region no spacecraft had ever entered — the 2,000-kilometer gap between Saturn and its innermost rings. The data it collected upended what scientists thought they knew about the rings' age, mass, and origin, and revealed a magnetic field so perfectly symmetrical it has no right to exist.