An Old Moon of Saturn Might Have Put a Ring on It

Saturn’s rings are one of the most iconic structures in the solar system, but their genesis has long been up for debate. New research suggests that the spectacular rings

may have been born out of the death of an icy moon. Saturn is a dynamic system. Besides those fascinating rings, one if its moons, Titan, is moving rapidly away from the

planet at about 4 inches (11 centimeters) per year (our own Moon moves away from Earth at a slow 1.5 inches annually). Saturn is also tilted at an angle of 26.7 degrees from the

plane of its orbit, and while that’s not all that uncommon in our solar system, the mechanism that caused this tilt is shrouded in mystery. However, a paper published yesterday in

Science may point to the missing link that could connect all these phenomena: anow-extinct icy moon of Saturn called Chrysalis. “If you throw a top on a table, after an

initial wobble period, it settles down into a motion where this spin axis of the top regularly makes a circle around the vertical. That’s the ‘precession’ of the top,” said Jack

Wisdom in a phone call with Gizmodo. Wisdom is a professor of planetary science at Massachusetts Institute of Technology and is lead author of the new study. Wisdom said that the

precession of Saturn and distant neighbor Neptune were at one point very close, or resonant. This resonance, coupled with Titan’s migration away from Saturn, could have explained

why the planet tilted.