WASHINGTON, April 14 (Xinhua) -- U.S. space agency NASA said Monday its Cassini spacecraft has documented the formation of a small icy object within the rings of Saturn that may be a new moon.
The discovery, published online by the U.S. journal Icarus, may provide clues to the formation of Saturn's known moons, including the cloud-wrapped Titan and ocean-holding Enceladus.
NASA said that images taken with Cassini's narrow angle camera on April 15, 2013 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 a 1,200-kilometer-long and 10- kilometer-wide arc about 20 percent brighter than its surroundings. Unusual protuberances in the usually smooth profile were also found at the ring's edge, the space agency said.
The researchers said they believe the arc and protuberances are caused by the gravitational effects of a nearby object, which is not expected to grow any larger, and may even be falling apart.
"We have not seen anything like this before," lead author Carl Murray of Queen Mary University of London in a NASA statement. "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."
The object, informally named Peggy, is too small to see in images so far. Scientists estimated it is probably no more than about a half mile (0.8 kilometer) in diameter.
"Witnessing the possible birth of a tiny moon is an exciting, unexpected event," said Cassini Project Scientist Linda Spilker, of NASA's Jet Propulsion Laboratory.
The researchers said that Cassini's orbit will move closer to the outer edge of the A ring in late 2016 and provide an opportunity to study Peggy in more detail and perhaps even image it.