NASA unveils new information about Saturn's irregular moons

Friday, 27 April 2012 11:54

April 27, 2012

NASA researchers said this week that the Cassini spacecraft had discovered a number of surprising characteristics about Saturn's moon Phoebe.

The federal space agency said this week the Cassini spacecraft, which has been exploring Saturn and its moons since 2004, relayed a host of data to Earth this week that upended the conventional wisdom regarding Phoebe. NASA scientists said that, using a multitude of engineering tools, Cassini sent back information about the moon's geology and chemistry.

As a result of the new information, NASA said it changed its categorization of Phoebe, affirming it is a planetesimal, meaning it is the relic of a planetary building block. Cassini has helped researchers gain an increasingly detailed look into the makeup and design of Saturn and its moons. According to NASA officials, Cassini has been one of the most successful space exploration programs of its kind, as data it has collected has effectively upended their understanding of the ringed planet.

"Unlike primitive bodies such as comets, Phoebe appears to have actively evolved for a time before it stalled out," according to Julie Castillo-Rogez, a planetary scientist at NASA's Jet Propulsion Laboratory, which is located in Pasadena, California. "Objects like Phoebe are thought to have condensed very quickly. Hence, they represent building blocks of planets. They give scientists clues about what conditions were like around the time of the birth of giant planets and their moons."

According to NASA, data from Cassini suggests Phoebe likely emanated in the Kuiper Belt, an icy region of space located beyond Neptune's orbit. Scientists noted, moreover, that the latest information also indicates that the composition of the moon likely shifted over its existence. NASA said Phoebe was likely spherical and hot when it first formed, and they added Saturn's gravitational pull likely captured the moon when it was traveling throughout the Solar System.

Unlike Saturn's other so-called irregular moons, Phoebe orbits the planet backwards. What's more, scientists asserted that Saturn's giant moons likely formed from the gas and dust encircling the planet. They also orbit in the same plane, according to experts. Researchers had long been puzzled by the orbit patterns of Saturn's irregular moons, according to Cornell University professor and Cassini team member Jonathan Lunine.

"By combining Cassini data with modeling techniques previously applied to other solar system bodies, we've been able to go back in time and clarify why Phoebe is so different from the rest of the Saturn system," he said.

NASA's findings were published in the April issue of the journal Icarus.