Study proposes a lost moon crashed into Titan and helped make Saturn's rings
Feb 24th 2026
Researchers using Cassini data and simulations say a collision between Titan and a now-missing moon hundreds of millions of years ago can explain Titan's fast orbital drift, Saturn's tilt, the origin of Hyperion and possibly the rings.
- Titan is about half the size of Earth, larger than Mercury, and is moving away from Saturn at about 11 centimeters per year.
- New research published on ArXiv and accepted in The Planetary Science Journal combines Cassini data and simulations to propose a collision between Titan and an extra moon about half a billion years ago.
- The hypothesized impact would have transferred mass to Titan and altered Saturn's spin, helping explain the planet's 26.7 degree tilt and a mismatch with Neptune's orbital resonance.
- The collision could have produced Hyperion or left debris that later formed that irregular moon, which is about 5 percent of Titan's diameter.
- Titan's changed orbit may have later disturbed inner moons and led to collisions that produced Saturn's rings perhaps 100 million years after the main impact.
- A February paper finding a young Titan surface of around 300 million years supports a recent disruptive event in the Saturn system.
- Cassini's measurements from 2004 to 2017 revealed the rapid outward motion of Titan and provided key constraints for the new model.
- NASA's Dragonfly mission, launching in 2028 and arriving around 2034, could test aspects of the collision hypothesis by analyzing Titan's surface and composition.