Astronomers have found new traces of active geysers in Europe
An analysis of the data collected by the Galileo probe in 1997 helped planetary scientists find yet another proof that there are active geysers in Europe, the satellite of Jupiter.
This will simplify the search for life in its waters, say scientists in an article published in the journal Nature Astronomy.
"Why did it take us 20 years to detect this surge of activity of geysers?" Firstly, Galileo's scientific team simply did not expect to see them and did not look for their traces in the data. Secondly, the discovery of this eruption required the calculation of very complex computer models that simply could not be created in 1997, "says Xianzhe Jia of the University of Michigan in Ann Arbor, USA.
On Europe - one of the four largest satellites of Jupiter, discovered by Galileo, under the multikilometer layer of ice there is an ocean of liquid water. Scientists consider the ocean of Europe as one of the probable sanctuaries of extraterrestrial life. In recent years, astronomers have found out that this ocean exchanges gases and minerals with ice on the surface, and also confirmed the presence in it of substances necessary for the existence of microbes.
The first possible traces of the existence of geysers in Europe were found in 2012, when the American astronomer Lorenz Roth (Lorenz Roth) discovered on the ultraviolet photographs of Europe, obtained with the help of the Hubble, traces of unusual "bright spots" in the region of the south pole of the planet. Ros and his team counted these spots as eruptions of geysers rising to a height of 200 kilometers from the surface of Europe.
These observations attracted the attention of NASA scientists, and they conducted several additional observation sessions for this moon in 2014, during which Hubble recorded three episodes of eruption of geysers. A year ago, scientists found new hints of their existence, watching the changes in the ultraviolet radiance of Jupiter, generated by water discharges from Europe.
These observations, as Jia relates, raised doubts in some planetologists, since they were carried out at the limit of sensitivity and resolving power of the Hubble. Similar changes in the brightness of the luminescence of Jupiter, as noted by skeptics, could have arisen accidentally due to errors in the operation of telescope instruments, or they can be associated not with geysers in Europe, but with other events in the vicinity of the giant planet.
Jia and his colleagues managed to find "first independent confirmation" of the fact that these geysers actually exist, studying the data that the Galileo probe collected during flights over Europe.
The scientists drew attention to the fact that the NASA automatic station in December 1997 descended to the surface of the moon of Jupiter at the point where geysers were found on Hubble images. This prompted them to check all the data that the probe received during this rapprochement with Europe.
As planetologists discovered, during this approach the probe was in a strange zone, where the plasma density was unusually high, and the magnetic field strength of Jupiter was higher than usual. The scientific team of Galileo did not pay attention to this, but the analysis of Jia and his colleagues showed that this anomaly arose as a result of the probe flying through a cloud of vapor that arose after another emission of geysers.
Such a discovery, as Jia notes, will be especially interesting for the team of the probe "Europe-Clipper", which will go to the moon of Jupiter in the middle of 2020 to search for traces of life in its bowels. The presence of geysers on Europe means that it does not have to drill a many-kilometer layer of ice on its surface in order to "taste" its waters for taste, scientists conclude.