Carbon dioxide detected on Jupiter's moon Europa comes from the vast ocean beneath its icy shell, research using James Webb Space Telescope data indicated on Thursday, potentially bolstering hopes the hidden water could harbour life.
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Scientists are confident there is a huge ocean of saltwater kilometres below Europa's ice covered surface, making the moon a prime candidate for hosting extra terrestrial life in our Solar System.
But determining whether this concealed ocean has the right chemical elements to support life has been difficult.
Carbon dioxide as been detected on Europa's surface, but whether it rose up from the ocean below remained an open question.
Aiming to find an answer two U.S. teams of researchers used data from the Webb telescope's near infrared spectrometer to map CO2 on the surface of Europa, publishing their results in separate studies in the journal Science.
The most CO2 was in a 1,800 kilometre wide area called Tara Regio, where there is a lot of "chaos terrain" with jagged ridges and cracks.
Exactly what creates chaos terrain is not well understood, but one theory is that warm water from the ocean rises up to melt the surface ice, which then re freezes over time into new uneven crags.
The first study used the Webb data to look at whether the CO2 could have come from somewhere other than the ocean below – hitching a ride on a meteorite, for example.
Samantha Trumbo, a planetary scientist at Cornell University and the study's lead author, said they concluded that the carbon was "ultimately derived from the interior, likely the internal ocean."
But the researchers could not rule out that the carbon came up from the planet's interior as rock like carbonate minerals, which irradiation could then have broken apart to become CO2.
"So now we've got salt, we've got CO2: we're starting to learn a little bit more what that internal chemistry might look like," Trumbo said.
Looking at the same Webb data, the second study also indicated that "carbon is sourced from within Europa." ■