NASA’s Cassini spacecraft has documented the formation of a small icy object within the rings of Saturn that may be a new moon.
Images show disturbances at the very edge of Saturn’s A ring — the outermost of the planet’s large, bright rings. One of these disturbances is an arc about 20 percent brighter than its surroundings, 1,200 kilometers long and 10 kilometers wide. Scientists also found unusual protuberances (above) in the usually smooth profile at the ring’s edge. Scientists believe the arc and protuberances are caused by the gravitational effects of a nearby object. Details of the observations were published online April 14 by the journal Icarus.
The object is not expected to grow any larger and may even be falling apart. But the process of its formation and outward movement aids in understanding of how Saturn’s icy moons, including the cloud-wrapped Titan and ocean-holding Enceladus, may have formed in more massive rings long ago. It also provides insight into how Earth and other planets in the solar system may have formed and migrated away from the sun.
“We have not seen anything like this before,” said Carl Murray of Queen Mary University of London, the report’s lead author. “We may be looking at the act of birth, where this object is just leaving the rings and heading off to be a moon in its own right.”
For more on the discovery, see the NASA press release.