It is becoming more and more possible that, in the end, the first extraterrestrial life form we encounter will not be in Martebut much further away, on Enceladus, the frigid moon of Saturn.
Numerous studies, in fact, had already shown that its great subterranean ocean, buried under a thick layer of ice and heated by the gravitational shocks of Saturn, contains most of the basic elements for the development of life. Most, yes, although one was missing.
But that just changed. This was announced just a few days ago Frank Postberg, from the Free University of Berlin, during the Europlanet Science Congress recently held in Granada. Postberg and his team, in fact, have discovered that there is also phosphorus on Enceladus, which means that this distant ice moon houses each and every one of the elements necessary for life as we know it to exist.
Here on Earth, all forms of life contain six essential elements: carbon, hydrogen, nitrogen, oxygen, phosphor y sulfur. And the presence of all of them, except phosphorus, had already been confirmed on Enceladus, in combination with the waters of its inner ocean. For this reason, and despite the fact that this moon was already considered one of the most favorable scenarios, many believed that the lack of phosphorus would prevent life from forming.
in E-ring
But now the Enceladus phosphor has appeared, and it has done so in the e-ring of Saturn. For more than ten years, between 1999 and 2009, the Cassini mission, which operated until its scheduled suicide against the large ringed planet in 2017, collected small grains of icy rock from this ring of Saturn. The E ring is powered by the ‘jets’ of ice vapor that Enceladus continuously launches into space, formed from the water of its ocean. But previous analyzes of these tiny grains, the last in 2009, failed to find any trace of phosphorus.
Something that Postberg and his colleagues seem to have just achieved with a new analysis carried out with more advanced techniques than those available at the time. Enceladus now satisfies what is generally considered one of the most stringent requirements for habitability.
The 2009 analyzes could only look at average grain spectra, and also lacked good reference spectra of known, laboratory-derived compounds to compare with Cassini samples to determine the presence of phosphorus.
But now, Postberg and his team have analyzed many more individual grains, comparing their spectra with the high-resolution spectra that other research groups have been capturing in their labs over the decade since the first analysis.
Between 100 and 1,000 times more than on Earth
In total, the researchers analyzed more than a hundred grains, and nine of them showed “without a doubt” the unmistakable trace of phosphorus, in the form of phosphates. Based on the levels of phosphorus present in the grains, Postberg believes that the Enceladus ocean has relatively high levels of this element. “We are talking about a concentration that is between 100 and 1,000 times greater than that found in our terrestrial oceans,” said the scientist during his conference.
Now, with all the necessary elements present, all that remains is to take the final big step: send a new mission there to search for life. Something that, by the way, will happen soon, since Enceladus is precisely one of NASA’s priority objectives for the next decade.