|A spacecraft orbiting Jupiter has found organic compounds on two of the giant planetís moons ó which raises hopes that all the building blocks for life could be present on another Jovian moon named Europa.|
Jet Propulsion Laboratory
Europa Fact Sheet
Possibility of Life on Europa
NASA: The Exobiology Branch
got the flour and sugar and the water to make the dough. And thereís a
suggestion that the oven is on.í
ó THOMAS B. MCCORD
University of Hawaii planetary scientist
ORGANIC COMPOUNDS such as carbon dioxide, sulfur dioxide, cyanogen and
hydrocarbons were detected on Callisto and Ganymede by a spectrometer aboard
the Galileo spacecraft, which is orbiting Jupiter.
The compounds may have been introduced to Callisto and Ganymede by meteorites striking the surface, said Robert W. Carlson, principal investigator for the Near Infrared Mapping Spectrometer experiment at NASAís Jet Propulsion Laboratory.
Even though such substances are thought to be among the prerequisites for life, Carlson said itís unlikely that life could ever develop on those two moons. Scientists consider the presence of complex organic compounds only one of at least three necessities for life; the others are water and an energy source. Callisto and Ganymede lack water and are relatively cold.
However, the discovery of organic compounds on those two moons indicate that such compounds could be similarly present on Europa.
Scientists believe that oceans of liquid water could lie beneath Europaís icy surface, with warmth welling up from undersea vents. Exotic life forms have evolved on Earthís ocean floor under similar conditions.
ìIf I was going to put any bets on anything, I would put it more toward Europa than toward Calliston and Ganymede,î Carlson said.
QUESTIONS STILL UNSETTLED
The new findings from Galileo were published in the Oct. 10 issue of the journal Science. The studyís lead author, University of Hawaii planetary scientist Thomas B. McCord, cautioned that the new results alone could not settle the question of whether Europa could harbor life.
McCord compared the research progress to how a cake is made.
ìWeíve got the flour and sugar and the water to make the dough,î McCord said. ìAnd thereís a suggestion that the oven is on.î
But assembling the ingredients does not mean the cake has been made, he said. Nevertheless, he and other scientists said more attention would be focused on Europa as the likeliest suspect for life elsewhere in the solar system.
finding increases the plausibility for life on Europa.í
ó DALE CRUIKSHANK
Ames Research Center
Dale Cruikshank, a research scientist at NASAís Ames Research Center, said
Europa already ìis the subject of very special interest.î
ìThis finding increases the plausibility for life on Europa,î Cruikshank said. ìIt also supports the idea that there were organic molecules streaming throughout the solar system.î
Future study would be aimed at determining whether organic compounds might lie beneath Europaís frozen surface.
A GROWING EFFORT
The study of Jupiterís moons is part of a growing effort by astronomers and planetary experts to find evidence of life within the solar system. A major goal of NASAís Mars exploration, for example, is to search for the fingerprints of ancient life on the Red Planet.
Researchers say it is unlikely that life exists on present-day Mars, which has a thin atmosphere, chilly temperatures and no apparent liquid water. But they increasingly believe that the planet once had vast pools of water, a thicker atmosphere and warmer temperatures ó all factors that are conducive to life.
The Associated Press contributed to this report.