Could liquid water be found in abundance on the icy surface of Europe, a moon of Jupiter? This is the hypothesis raised in a new study. But that is not at all certain.
Life outside our planet has never been identified yet, but if there is one promising place, it is certainly Europe. This moon of Jupiter is one of the places in the solar system that seems to be one of the most habitable (which does not mean habitat). A study published in Nature April 19, 2022 revives the issue. ” Shallow water bags may be common in Europe’s rising ice shell [son] potential habitability “, we read in a press release presenting the work.
The presence of water in Europe is not in itself new, explains Ines Belgacem, a postdoctoral planetary scientist at the European Space Agency (ESA), a specialist in Jupiter’s icy moons. ” Water in Europe, that’s all! There is icy water on the surface and water in the depths. […] We know that there is an ocean under the ice sheet, thanks to indirect measurements. On the other hand, we do not have a very strong limitation on the thickness of the ice sheet and the thickness of the ocean, before reaching the mantle. There must be about 25 miles of ice, then the ocean, then the mantle. »
Today there is no more talk of the existence of the ocean. ” What is being discussed are the implications of the existence of this ocean: is there a habitable environment? “, Sums up the expert. What makes Europe such a viable place in search of life, or at least habitability, is the close connection between its ocean and its rocky mantle: the two are in contact. ” So we have chemical activity. However, if we make the analogy with what we know on Earth, life appeared there in the oceans. »
It is in this context that the study raises a possibility: the presence of liquid water deposits (therefore shallow, unlike the ocean) almost everywhere in the icy layer of the moon Europa. They would not only be pockets located here and there, but a much more present phenomenon in this star. The hypothesis is encouraging, because Europe’s thick ice shell is an intimidating barrier to this promising ocean.
The authors consider that, in short, it is less of a barrier than a dynamic place, perhaps habitable. However, This study does not allow us to confirm this at all.these results are not derived from direct observations.
” It is comparative planetologyadds the expert. The planet we have the most access to is Earth. But drawing parallels with the Earth is complicated by icy moons. The nearest substitute is the North Pole. The authors work here on a geological structure in Greenland, a “double ridge” (imagine two mountains, with a valley in the middle) which has been compared to the structures seen in Europe. ” Studying this double radar wrinkle, they realized that it had a rise in liquid water, which could explain the existence of these blows. By analogy, this could be formed in Europe. »
Here, then, it is the existence of a double wrinkle that is discovered and analyzed (exhaustively) on Earth. ” We are not yet able to do this type of analysis in Europe, we do not have the data or the observation time we need. Says Inés Belgacem. The specialist emphasizes an obvious limitation to this work: the orders of magnitude are very different between the wrinkles studied in Greenland and those in Europe. ” These ripples form over hundreds of miles, which means we should have water that has risen along that entire length. We are not on the same scale. »
We understand, however, why the hypothesis brings to light the question of Europe’s habitability, even if the conclusion of the study is not certain. Ines Belgacem lists the underlying questions: “ Does this surface liquid water have a direct relationship with the ocean? Could this facilitate the study of habitability in the future? Could it be examined with a future landing in a simpler way than the ocean itself? »
Impossible to decide at the moment, says the scientist, or even in the near future. ” The next JUICE and Europa Clipper missions will arrive on Jupiter around 2030remembers the planetologist. Then we will start to have more advanced data to analyze this kind of thing and maybe help to decide. In the longer term, in 2040, it is even planned to try to place probes on the surface of Europe, to obtain measurements in situ.
While waiting for these deadlines, scientists have every interest in making hypotheses, such as that of this new study. ” We try to understand the history and the mechanisms of formation of the different terrains. And if we can discriminate between the models, it helps our future exploration of Europe concludes the scientist.