Life in the Solar System

Besides Earth, where in the solar system is complex life most likely to be found?

Many would say Mars. But if life exists on that dry, cold planet with its weak atmosphere, it’s probably microbial. However, complex life just might have developed in the far reaches of our system, on moons orbiting Jupiter.

(NASA art showing Europa’s subsurface ocean.)

Earlier probes have shown that oceans underlie the heavy ice coverings of Jupiter’s moons Europa and Ganymede. Their interiors are kept warm through interactions with the gravity and magnetic field of the huge planet.

Officials of NASA and the European Space Agency met in mid-February in Washington, D.C., and agreed to pursue a joint project to study the four largest Jovian moons. (They also agreed to plan a potential visit to Saturn’s moons Titan and Enceladus.) A NASA press release quotes Ed Weiler, associate administrator for the agency’s Science Mission Directorate: “Although the Jupiter system mission has been chosen to proceed to an earlier flight opportunity, a Saturn system mission clearly remains a high priority for the scientific community.”

The joint “Europa Jupiter System Mission” tentatively will launch in 2020, with two probes. NASA’s robot craft, Jupiter Europa, would explore Europa, while ESA’s Ganymede Jupiter would examine the largest moon in the solar system, Ganymede. Both satellites are believed to have oceans under the ice.

The project also will study the remaining great moons of Jupiter, Io and Callisto, as well as the gas giant itself.

“Europa is a fascinating place with an ocean that might be only tens of kilometers below the surface,” said Robert Pappalardo, Europa Orbiter Study scientist, in a NASA video. The ocean impacts the surface “through eruptions, through icy convection – blobs of warm ice moving up to the surface through cracking, the breaking of the ice.”

Europa’s ocean may be in contact with a rocky mantle, which should improve the chances of life as the interior minerals could provide nutrients that life needs. Ganymede may have an “ocean sandwich,” in Pappalardo’s term; the water could be between ice layers.

“It’s not out of the question that if there are liquid water oceans down there and there’s heat and there’s energy, that there could possibly be life,” he added.

To learn about the proposal, CLICK HERE. The site, presenting a transcript of Pappalardo’s comments, also links to his video, which can be accessed by playing the “vodcast.”

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