December 11, 2013
Clay-Like Substance Found On Jupiter’s Moon Europa
Lee Rannals for redOrbit.com - Your Universe Online
Jupiter’s icy moon Europa appears to have clay-type minerals on its surface, according to new data from NASA’s Galileo mission. Scientists at the American Geophysical Union meeting in San Francisco say they have identified clay-like minerals on Europa for the first time. This finding could also imply that Europa carries organic materials.
"Organic materials, which are important building blocks for life, are often found in comets and primitive asteroids," said Jim Shirley, a research scientist at NASA's Jet Propulsion Laboratory, Pasadena, California. "Finding the rocky residues of this comet crash on Europa's surface may open up a new chapter in the story of the search for life on Europa.”
Scientists believe that Europa may be one of the best locations in our solar system to find extraterrestrial life. The moon has a subsurface ocean in contact with rock, an icy surface that mixes with the ocean below, salts on the surface that create an energy gradient, and a source of heat.
Researchers analyzing Galileo data spotted the clay-type minerals known as phyllosilicates in near-infrared images from Galileo taken in 1998. These images are low resolution by today’s standards, so the team is applying a new technique for pulling a stronger signal for these materials out of the noisy picture.
The phyllosilicates appear in a ring about 25 miles wide, about 75 miles away from the center of a crater site. The leading explanation for this pattern is the splash back of material ejected when a comet or asteroid hit the surface of Europa at an angle of 45 degrees or more from the vertical direction.
A shallow angle would allow some of the space object’s original material to fall back to the surface. A more head-on collision would have vaporized the material or driven the clay below the moon’s icy surface. The other explanation for the phyllosilicates is that the material made its way up from Europa’s interior. However, NASA said that this scenario is unlikely because scientists believe the phyllosilicates would have had to travel up 60 miles in some areas.
The scientists said that if the body that brought the phyllosilicates to Europa was an asteroid then it was about 3,600 feet in diameter. If the culprit was a comet then it was likely about 5,600 feet in diameter, which is roughly about the same size comet ISON was before losing in a battle with the sun a few weeks ago.
"Understanding Europa's composition is key to deciphering its history and its potential habitability," Bob Pappalardo of JPL, the pre-project scientist for a proposed mission to Europa, said in a statement. "It will take a future spacecraft mission to Europa to pin down the specifics of its chemistry and the implications for this moon hosting life."