Scientists already had indications that there was a large ocean beneath the ice sheet of Jupiter’s moon Europa. Now, with this finding, it could become the first habitable place of our Solar System, in addition to the Earth.
Forty years ago, a Voyager spacecraft took the first foreground images of Europa, one of Jupiter’s 79 moons.
These revealed brown cracks that cut the icy surface of the moon, which gives Europa the appearance of a venous eyeball.
Missions to the outer solar system in subsequent decades have accumulated enough additional information about Europa to make it a priority research objective in NASA’s search for life.
What makes this moon so attractive is the possibility that it has all the necessary ingredients for life.
Scientists have evidence that one of these ingredients, liquid water, is present beneath the icy surface and that it can sometimes break into space in huge geysers.
But nobody has been able to confirm the presence of water in these plumes by directly measuring the water molecule itself, until now …
Recently, a team led by NASA’s Goddard Space Flight Center has detected water vapor for the first time on the surface of Europa.
To do this, the vapor was measured by observing this moon through one of the largest telescopes in the world, the WM Keck Observatory on top of the Mauna Kea volcano, Hawaii.
Confirming that there is water vapor over Europa helps scientists better understand the inner workings of the moon.
For example, it helps support an idea: that there is an ocean of liquid water, possibly twice as large as Earth’s, splashing beneath the ice sheet of miles of this moon – an idea that is almost a certainty.
Some scientists suspect that another source of water for plumes could be shallow deposits of melted water ice not far below the surface of Europa.
It is also possible that Jupiter‘s strong radiation field is removing water particles from Europe’s ice sheet, although recent research argued against this mechanism as the observed water source.
«Essential chemical elements (carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur) and energy sources, two of the three requirements for life, are found throughout the solar system.
But the third, liquid water, is somewhat difficult to find beyond Earth, ”said Lucas Paganini, a NASA planetary scientist and who led the water detection investigation.
“While scientists have not yet detected liquid water directly, we have found the following best option: water in the form of steam.”
Paganini and his team reported in the journal Nature Astronomy on November 18 that they detected enough water release from Europa (2,360 kilograms per second) to fill an Olympic pool in minutes.
However, scientists also discovered that water appears infrequently; at least not in quantities large enough to detect them frequently from Earth.
In fact, surface water molecules were detected only once in 17 nights of observation.
“For me, the interesting thing about this work is not only the first direct detection of water on Europa but also the lack of it within the limits of our detection method,” Paganini concluded.
Soon we could find definitive answers about the mysteries of Europa and its habitability level.
The Clipper mission to this moon is expected to be launched in the middle of next year, to finally round off decades of investigation of other missions.
When it arrives on Europa, Clipper will orbit it and make a detailed survey of its surface, interior, atmosphere, subsurface ocean, and other characteristics.
It will also take pictures of the geysers and perform analysis of the atmospheric molecules with mass spectroscopes.
And if that were not enough, it will leave everything ready for the next step, finding an ideal place for NASA to send a robot to collect samples.