by One grain of ice was expelled Jupiterand moon ocean Europeif captured by NASA to come Clip Europe spacecraft, may be enough to reveal evidence of alien life, suggests a new experiment.
“With suitable instrumentation, such as the Surface Dust Analyzer on NASA’s Europa Clipper space probe, finding life, or traces of it, on icy moons may be easier than we thought,” said Freie’s Frank Postberg Universität Berlin in a. statement. Postberg is a co-author of a new study that describes the findings.
The first mission dedicated to this frozen Jovian moon, Europa Clipper is currently scheduled to blast off in October 2024. It is expected to arrive in 2030, and then make nearly 50 close flybys of Europa, skimming the icy surface at altitude as low as 25 kilometers (16 miles). The main aim of the mission is to learn more about the habitability of Europa’s subsurface ocean and the thickness of the overlying ice shell. The mission isn’t designed to find life, to be clear – but scientists now realize there may be a way.
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One of Europa’s oceanic satellites Enceladusa small icy body in orbit around the enclosing planet Saturn. In 2006, the Cassini mission to Saturn he discovered plumes of water vapor belching out from Enceladus’ ocean through large breaks in the surface, called “tiger stripes.”
In 2014, the Hubble Space Telescope a plume-like appearance was observed rising 200 kilometers (125 miles) above Europa’s surface. Two years later, he saw another plume coming from the same location. Then, in 2018, NASA Astronomers know that the old Galileo’s explorationwhich actually operated in orbit around Jupiter between 1995 and 2003 three plumes were flown.
Assuming that Europa Clipper could fly through the moon’s icy plume, scientists led by Fabian Klenner from the University of Washington in Seattle investigated whether the spacecraft’s Surface Dust Analyzer (SUDA) could detect any life carried up from the ocean. the thigh. SUDA is designed to study Europa’s surface ice particles and dust sputtered in space as the moon constantly being bombarded by micrometeorites, but perhaps he could analyze ice grains in the plumes, too.
It wouldn’t be practical enough to simulate the high-velocity impacts of an ice grain on the instrument in a laboratory, so instead Klenner’s team fired a thin, fast jet of water vapor loaded with a bacterium called Sphingopyxis alaskensis into a vacuum chamber. Sphingopyxis alaskensis is found in ocean waters off the coast of Alaska, and is at home in cold temperatures and few nutrients.
It is one of the closest things we have to life World that could live in Europa’s oceans.
More significant for the Europa Clipper’s ability to find such life, the bacteria are “very small, so they could theoretically fit into ice grains emitted from an ocean world like Enceladus or Europa,” which Klenner said in the statement.
The vacuum caused the water jet to freeze into droplets that froze as ice grains. The grains were then studied with a mass spectrometer, mimicking how SUDA will study any grain it extracts in the real world. The results of the experiment showed that Sphingopyxis alaskensis, or at least the parts of it that form ocean scum, could be detected from studying a single grain of ice.
“We have shown that even a small fraction of cellular material could be identified with a mass spectrometer on board a spacecraft,” said Klenner. “Our results give us more confidence that, using future instruments, we will be able to detect life forms similar to those on Earth, which we increasingly believe may be present on sea moons.”
Europa Clipper’s instruments cannot detect DNA, but SUDA could detect fatty acids and lipids, which can form biological cell membranes. In the Earth’s oceans, lipid membranes contribute to the thin film of ocean scum on the surface of the water. It is this scum that gives sea spray its distinctive smell.
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“For me, it’s more exciting to look at lipids, or for fatty acids, than to look for DNA building blocks, and the reason is that fatty acids seem to be more stable,” Klenner said.
If life in Europa’s oceans contains lipid membranes, the biological components are more likely to remain in one piece for Europa Clipper to detect.
The results were published on 22 March in the journal Scientific Progress.
