Artist’s illustration of a possible NASA probe on the surface of Jupiter’s icy, ocean-harboring moon Europa. Credit: NASA/JPL
If there are any signs of life exist on Jupiter’s icy moon Europa, they might not be as hard to find as scientists thought, a new study reports.
The 1,900-km-wide (3,100 kilometers) of Europe is home to a huge ocean under the icy shell. What’s more, astronomers think that this water is in contact with the moon’s rocky core, making a variety of complex and intriguing chemical reactions possible.
Researchers are, therefore, consider Europe as one of the solar energy system is the best bet to make the port of extraterrestrial life. Europe is also a geologically active world, so samples from the buried ocean could routinely make it to the surface through localized upwelling of the ocean itself, for example, and/or by means of geyser-like outgassing, evidence of which has been spotted multiple times by NASA’s Hubble Space Telescope. [Photos: Europa, Mysterious Icy Moon of Jupiter]
NASA wants to hunt for these monsters in the not-too-distant future. The agency is the development of a flyby mission called Europa Clipper, which is scheduled for launch in the beginning of 2020. The Clipper will study Europe close-up during dozens of proximity, some of that could zoom by the moon is suspected water-vapor plumes. And NASA is also working on a possible post-Clipper lander mission that would search for evidence of life on or in the vicinity of the Europan surface.
It is unclear, however, how deep a Europa lander would have to dig in order to have a chance of finding something. That’s because Europa orbits within the radiation belts of Jupiter and is bombarded by fast-moving charged particles, which can change amino acids and other potential biosignatures in the broth.
That is where the new study comes.
NASA scientist Tom Nordheim and his colleagues modeled Europe radiation of the environment in detail, explain how bad the things from place to place. Then they have these results combined with the data from laboratory experiments to document how fast various doses of radiation carve up of amino acids (a stand-in here for complex biomolecules in general).
The researchers found a significant variation, with some Europan locales (equatorial regions) to about 10 times the radiation pounding of the others (middle and higher latitudes).
In the most benign places, the team determined, a lander would probably have to dig only 0.4 inch (1 cm) or so in the ice to find recognizable amino acids. In the high-blast areas, the target depth on the order of 4 to 8 inches (10 to 20 cm). (This is not to imply that potential Europan organisms could live at such depths, however; doses are high enough to cook even the hardiest Earth microbes, study team members said.)
That last range is still quite manageable, said Nordheim, who is based at the California Institute of Technology and NASA’s Jet Propulsion Laboratory, both in Pasadena.
“Even in the most severe radiation zones in Europe, you really don’t have to do more than scratching below the surface to find material that is not significantly altered or damaged by radiation,” he told Space.com.
That is good news for the potential lander mission, Nordheim added: With exposure to radiation doesn’t seem to be the limiting factor, planners feel free to focus on the areas of Europe most likely to harbor fresh ocean deposits — the fall-out zone below a plume, for example — where they are located.
Scientists still have not identified such a promising touchdown areas; the Europe images captured to date is just not sharp enough. But Europe Clipper work should things change, Nordheim said.
“When we get the Clipper exploration, high-resolution photos — it’s just a very different picture,” he said. “That Clipper exploration is really the key.”
The new study was published today (July 23) in the journal Nature Astronomy.
Originally published on Space.com.