New clues on the environment favorable to life in the oceans of Europa and Enceladus

Plumes on Europa (Image NASA, ESA, W. Sparks (STScI), and the USGS Astrogeology Science Center)
Plumes on Europa (Image NASA, ESA, W. Sparks (STScI), and the USGS Astrogeology Science Center)

Yesterday, NASA held a press conference to explain the latest news about the studies of alien oceans. The attention was focused on the two most popular underground oceans, the one in Jupiter’s satellite Europa and the one in Saturn’s satellite Enceladus. There are confirmations of plumes from Europa, also described in an article published in “The Astrophysical Journal Letters”. The presence of molecular hydrogen in the Enceladus ocean was announced, also described in an article published in the journal “Science”.

Plumes that rose from the surface of Europa were identified in observations carried out with the Hubble Space Telescope in recent years and its study was presented in September 2016. New observations made in 2016 still show plumes that rose from the same area that rise up to about 100 kilometers (about 62 miles) above the surface. It’s an important confirmation of their existence and the fact that it wasn’t a momentary phenomenon.

Another step forward was made by comparing the area in which the plumes were detected using the Hubble Space Telescope with the data collected in the ’90s by NASA’s Galileo space probe, which also examined Europa in the course of its mission in Jupiter’s system. The result was that that area was identified as abnormally warm with features on its surface that appeared to be fractures in the ice crust.

It’s a situation similar to that existing on Enceladus, where the geysers and the conditions in the area where they erupt are well documented as well as the hydrothermal activity, illustrated in the image at the bottom, that generate them. New evidence that there are activities in that ocean are interesting because if there are the right elements along the necessary energy, chemical reactions that create complex molecules, perhaps even life forms, can happen.

The fact that in recent years there was the Cassini space probe to investigate what’s happening on Enceladus is a great help to get useful data. For example, mission managers were able to bring it down to 49 kilometers (about 30 miles) above this moon’s surface almost exactly above the plumes to analyze their contents. The result is that Cassini’s INMS (Ion and Neutral Mass Spectrometer) instrument obtained data to try to understand the amounts of water, carbon dioxide and molecular hydrogen.

In particular, the scientists were interested in hydrogen because it could be a key energy source for life forms born in that underground ocean. The result is another confirmation of the presence of hydrothermal springs in the depths of Enceladus with conditions that show a really interesting potential. In fact they’re similar to those existing in the depths of Earth’s oceans, where there are life forms that survive without photosynthesis.

For both Europa and Enceladus we’re still far from understanding whether there are life forms but so far every new discovery seems to offer new clues in favor of such a possibility. Mind it, so far those are still clues in favor of the potential that these two moons have and there’s still a lot to discover in order to have real answers.

Unfortunately, the Cassini space probe is running out of fuel so its mission will end in a few months. At NASA they’re thinking about a possible new mission in the Saturn system with the right instruments to study the Enceladus’ ocean but who knows how many years it will take for to have the chance to launch a new space probe. Instead, a mission to study Europa has been in its planning stage for some years so a space probe could study this moon’s ocean in a few years.

Ho hydrothermal activity works on Enceladus (Image NASA/JPL-Caltech/Southwest Research Institute)
Ho hydrothermal activity works on Enceladus (Image NASA/JPL-Caltech/Southwest Research Institute)

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