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The icy moon of Jupiter Europe it’s an astrobiological beacon, literally shining in deep darkness away from the sun, suggests a new study.
Jupiter’s intense radiation environment likely illuminates Europa’s icy shell, towering over a huge potentially habitable ocean of salty liquid water, the researchers found.
“If Europa weren’t under this radiation, it would look like our moon appears to us – dark on the shadow side,” study lead author Murthy Gudipati, a scientist at NASA’s Jet Propulsion Laboratory (JPL) in Southern California, he said in a statement. “But because it is bombarded by Jupiter’s radiation, it glows in the dark.”
Photo: Europa, Jupiter’s mysterious icy moon
Gudipati and his team set out to study how organic molecules in Europa’s ice shell could be affected by charged particles whizzing 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 environmental testing, which resulted in an electron beam facility in Maryland. They tested the effects of radiation on simulated Europa surfaces composed of water ice and various suspected salts, including sodium chloride and magnesium sulfate.
The radiation made the samples glow. This wasn’t particularly surprising, the researchers said. The phenomenon is well understood: fast-moving particles have entered the sample, exciting the molecules underground and generating a glow.
“But we never imagined that 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 looked different. And we just stared at it for a while and then we said, ‘This is new, right? This is definitely 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 sunlit day side of Europa – has more than just a gee-whiz appeal. Its color and intensity could reveal key details about the composition of the moon’s icy shell, study team members said.
And, as Europa’s buried ocean water likely makes its way to the moon’s surface in places, “the way this composition varies could give us clues that Europa brings conditions suitable for life,” Gudipati said .
The color variation likely ranges from greenish to bluish to whitish, depending on the composition of the surface, team members said.
Scientists may be able to observe the glow up close relatively early, thanks to NASA Europa Clipper probe, which is expected to be launched in the mid-1920s. Clipper will orbit Jupiter but scan Europa over dozens of close passages, collecting data that will help researchers assess the moon’s habitability and plan a hunt for life. Europe lands on a mission. (The lander was commissioned by Congress, but at the moment it remains a concept, not a proper NASA mission. It will launch sometime after Clipper.)
Clipper’s team is reviewing 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 detectable by the spacecraft’s instruments, NASA officials said in the same statement.
“It’s not often that you stand in a laboratory and say, ‘We might find it when we get there,'” said Gudipati. “Usually it’s the other way around: you go there and you find something and try to explain it in the lab. But our prediction goes back to a simple observation, and that’s what science is about.”
Mike Wall is the author of “Out there“(Grand Central Publishing, 2018; illustrated by Karl Tate), a book about the search for alien life. Follow him on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or Facebook.
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