Leonard David's INSIDE OUTER SPACE

Jupiter’s icy moon Europa displays many signs of activity, including its fractured crust and a dearth of impact craters. Scientists continue to hunt for confirmation of plume activity.
Image Credit: NASA/JPL-Caltech/SETI Institute

Billions of dollars have been spent on the Red Planet Mars to divine whether that world is an extraterrestrial address for past and/or present life. The question of life on Mars is still breathing today as it was decades ago.

Meanwhile, the search for life beyond Earth quest is turning to yet another destination: One of Jupiter’s many moons, Europa.

Current Europa missions are under study focused on answering the question “Is Europa habitable?”

For one, the potential presence of water plumes on the satellite could present an opportunity to pursue the question of whether or not that moon is capable of supporting life.

Artist’s conception of water vapor plume erupting from the icy surface of Europa, a moon of Jupiter, based on data from the Hubble Space Telescope.
Credit: NASA/ESA/K. Retherford/SWRI

Fresh look

On the other hand, a fresh look at data collected by NASA’s Cassini spacecraft during its 2001 flyby of Jupiter shows that Europa’s tenuous atmosphere is even thinner than previously thought.

Furthermore, the Cassini data also suggests that the thin, hot gas around the moon does not show evidence of plume activity occurring at the time of the flyby. The new research provides a snapshot of Europa’s state of activity at that time, and suggests that if there is plume activity, it is likely intermittent.

So answering the question of life on Europa is far more challenging because measurements currently possible may provide only “ambiguous results” from a mission that either orbits or flies by Europa at relatively high velocity.

Next month, NASA’s Planetary Science Division is convening a workshop at NASA Ames Research Center to consider strategies to investigate Europa’s putative plumes for evidence of life.

“Europa is a complex, amazing world, and understanding it is challenging given the limited observations we have,” said Curt Niebur, Outer Planets program scientist at NASA Headquarters in Washington, D.C.

Scientists are currently using the NASA Hubble Space Telescope to conduct an extensive six-month long survey looking for plume activity, and the space agency is also studying various possible Europa missions for future exploration.