2023-09-21 18:15:10
Scientists are convinced that a vast ocean of salt water lies dozens of kilometers beneath Europa’s icy surface, making this moon an ideal candidate for harboring extraterrestrial life in our solar system.
However, it is difficult to determine whether this hidden ocean contains the chemical elements necessary for life to appear.
Carbon dioxide (CO2), which, along with liquid water, is one of the fundamental building blocks of this process, had already been detected on the surface of Europa, without its origin being able to be determined. .
To find out, two American teams of researchers used data from the James Webb space telescope, collected using its infrared observation instrument. They were thus able to map the surface of Europe, according to two studies published Thursday in the journal Science.
The largest amount of CO2 was found in an area 1,800 kilometers wide, called Tara Regio. This area is covered in “chaotic terrain”, made up of ridges and cracks, according to one of the studies.
It’s not clear what creates this jagged terrain, but it might be that relatively warm water from the underlying ocean rises to melt the surface ice, which refreezes over time and forms new bumps .
Table salt
The first study used information from the James Webb Telescope to determine whether the CO2 might come from elsewhere, such as a meteorite.
Conclusion: the carbon “ultimately comes from the interior, probably from the internal ocean of the moon”, explains to AFP Samantha Trumbo, planetary scientist at the American University of Cornell and lead author of the study.
In the Taga Regio area, scientists also detected the equivalent of table salt, making this area yellower than the rest of the white plains of Jupiter’s moon. An element which might also have emerged from the ocean.
“Now we have CO2, salt: we are starting to know a little more regarding the internal chemistry” of Europe, underlines the planetologist.
Using the same James Webb data, the second study also concludes that “carbon comes from within Europe”.
Europa, one of Jupiter’s three icy moons, is the target of two major space missions which must determine whether its mysterious ocean is conducive to the appearance of life.
“Missions futures”
The Juice probe of ESA, the European space agency, was launched last April, and that of NASA, Europa Clipper, is due to take off in October 2024.
They will take eight years to reach Jupiter, the giant of the solar system, and its large moons (Io, Europa, Ganymede and Callisto), discovered by Galileo in 1610.
Olivier Witasse, scientific manager of the Juice project for the ESA, considers the analyzes of the James Webb telescope “extremely interesting”. “This allows us to know more regarding this ocean, located deep under the ice and therefore rather inaccessible in the current state of space exploration,” he told AFP.
“It is one of the most fascinating places in the solar system in the search for life other than on Earth,” adds the scientist.
When the Juice probe makes two flights over Europe in 2032, it will collect “a wealth of new information”, he anticipates. Juice will also go to inspect Ganymede, which also has a subglacial ocean, and where carbon has been detected.
The Juice and Europa Clipper missions will not be able to directly find extra-terrestrial life, but only identify conditions conducive to its appearance. “We leave this challenge to future missions,” adds Olivier Witasse. In such an extreme environment, it might only be primitive life forms like bacteria.
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