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Jupiter’s frozen moon Europe is an astrobiological beacon, which literally glows in deep darkness away from the sun, a new study suggests.
Jupiter’s intensely radiant environment likely illuminates Europa’s icy shell, which covers a huge, potentially habitable ocean of liquid salt water, the researchers found.
“If Europa weren’t under this radiation, it would look like our moon – dark on the shaded side,” says lead study author Murthy Gudipati, a scientist at NASA’s Jet Propulsion Laboratory (JPL) in the south. from California. said in a press release. “But because it’s bombarded by radiation from Jupiter, it glows in the dark.”
Photos: Europe, the mysterious frozen moon of Jupiter
Gudipati and his team set out to study how organic molecules in Europe’s ice shell might be affected by charged particles that zoom around Jupiter at enormous speeds, trapped and accelerated by the giant planet’s powerful magnetic field. .
The researchers built an instrument called the Ice Chamber for Europa’s High-Energy Electron and Radiation Environment Testing, which they took to an electron beam facility in Maryland. They tested the effects of radiation on simulated European surfaces made up of water ice and various salts believed to be there, including sodium chloride and magnesium sulfate.
The radiation made the samples glow. It wasn’t terribly surprising, the researchers said. The phenomenon is well understood: fast-moving particles entered the sample, exciting molecules in the nearby subsoil and generating a glow.
“But we never imagined we would see what we ended up seeing,” study co-author Bryana Henderson, also of JPL, said in the same statement. “When we tried new ice compositions, the glow was different. And we all just looked at it for a while and then we said, ‘It’s new, isn’t it? Is it really a different glow? “So we pointed a spectrometer at it, and each type of ice had a different spectrum.”
This nocturnal glow – it won’t be visible on the sunny side of Europe – has more than a gee-whiz appeal. Its color and intensity could reveal key details about the makeup of the moon’s icy shell, study team members said.
And, because the water from the buried ocean of Europe probably makes its way to the moon’s surface in places, “the way this composition varies could give us clues as to whether Europa is harboring conditions conducive to life, ”Gudipati said.
The color variation is likely to range from greenish to bluish to whitish, depending on the composition of the surface, the team members said.
Scientists might be able to observe the glow up close quite quickly, thanks to NASA Europa Clipper probe, slated for launch in the mid-2020s. Clipper will orbit Jupiter but will scan Europe on dozens of overflights, collecting data that will help researchers assess the moon’s habitability and plan a hunt for the life Mission in Europe. (The lander has been commissioned by Congress, but it remains a concept for now, not a full-fledged NASA mission. It will launch shortly after Clipper.)
The Clipper team is examining the results of the new study, which was published online Monday, November 9 in the journal Nature astronomy, to determine whether Europa’s glow could be detected by the spacecraft’s instruments, NASA officials said in the same statement.
“It’s not often that you’re in a lab and say, ‘We might find this when we get there,'” Gudipati said. “Usually it’s the other way around – you go out there and find something and try to explain it in the lab. But our prediction comes down to just observation, and that’s what science is for.”
Mike Wall is the author of “Over there“(Grand Central Publishing, 2018; illustrated by Karl Tate), a book on the search for extraterrestrial life. Follow him on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or Facebook.
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