Study: Saturn's icy rings formed by doomed moons
by Steven Mostyn - Dec 13 2010, 09:55
The cold ring of truth? Image: NASA.
A new study conducted by scientists at the Southwest Research Institute in Boulder, Colorado, has this week posited that Saturn’s rings are the remnants of a massive moon that once orbited Earth’s distant neighbour.
According to study author and astronomer Robin Canup, the moon plunged into Saturn around 4.5 billion years ago due to a giant ring of hydrogen gas responsible for creating rocky satellites but also for dragging larger moons out of orbit.
The scientific theory centres on the predominantly icy composition of Saturn’s rings. Specifically, Canup believes a widely held theory regarding ring creation via moon-on-moon or asteroid collision is wide of the mark because the rings don’t contain enough rock debris.
The new theory suggests doomed moons were often pulled into Saturn, stripping them of their surface ice, which remained trapped in massive rings that gradually reduced over time as they fed into the creation of smaller, more stable moons.
“Planetary tidal forces preferentially strip material from the satellite’s outer icy layers, while its rocky core remains intact and is lost to collision with the planet,” outlines Canup in the study. “The result is a pure ice ring much more massive than Saturn’s current rings,”
“As the ring evolves, its mass decreases and icy moons are spawned from its outer edge,” she adds, “with estimated masses consistent with Saturn’s ice-rich moon interior to and including Tethys.”
The Southwest Research Institute study can be read online in the journal Nature.
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