Saturn's icy moon, Enceladus, is on everyone's lips since the announcement made by NASA last week. According to the agency, molecular hydrogen has been found in the subglacial ocean of Enceladus, which may be an indicator that the satellite may have an environment suitable for extraterrestrial life. Despite its very cold external nature, the ocean on Enceladus can be warm, especially in the deep part of it, scientists say. We are talking about temperatures up to 90 degrees Celsius. In general, if you are an astrobiologist or just a big space exploration enthusiast, then this news should definitely inspire you. Because, you know, aliens!
The discovery of hydrogen on a satellite is actually great news, but professional and amateur astronomers have long suspected that life might exist on Enceladus. In 2015, NASA's Cassini spacecraft flew through the geysers of Enceladus and collected samples of organic components. So, among 62 Saturian satellites, Enceladus became the most interesting overnight. How else? The presence of organic molecules and water means only one thing: Enceladus is suitable (or at least once was suitable) for life.
The question of today's article is what exactly can live in the ocean of this icy world? Of course, no one has an answer to this question yet, but isn't it interesting to at least speculate on this topic?
“I think that inside the solar system, if we find something [living], it will be some kind of microorganisms. If we find the remains of something extinct, then it is also likely to be some kind of microorganisms,”says Rocco Manicelli, astrobiologist at NASA.
It is unlikely, of course, that narwhals are splashing under the ice crust of Enceladus (but what if?), Since this world is still not as fabulous as it might seem at first glance. The surface of Enceladus reflects a lot of heat, so the temperature here always remains very low and often reaches -201 degrees Celsius. Of course, this does not exclude the possibility of life on it, but complex organisms are unlikely to be able to survive under such conditions.
“The key question here is how will living organisms survive here? Life needs to have a source of energy, as well as the ability to reproduce itself. What could be an energy source on Enceladus? The ice crust of the satellite is very thick, so sunlight is not suitable for microorganisms (if any) as an energy source,”says Manicelli.
If there is at least some life on Enceladus, then, most likely, it is concentrated around geothermal sources, which can also represent an ideal habitat, at least here on Earth. Recent studies that have found very ancient fossils of microorganisms have shown that such geothermal sources were essential for the origin of life on Earth. A wide variety of fauna can live here, ranging from tube worms to various types of shrimp. They all live in places where there is no access to sunlight. How do they survive? All thanks to chemosynthesis - a process, according to the publication Ocean Portal, with the help of which “microorganisms located at the lower levels of the food chain are able to obtain the necessary chemicals directly from geothermal sources,converting them into usable energy and food."
It is possible that Enceladus does not have all the necessary components that would allow the emergence of complex living organisms, but, according to new research, there is a high probability that the satellite can still support simple organisms. And who knows, maybe these microorganisms have found a way to use some other energy source available on the satellite and evolve accordingly. Obviously, the same narwhals. Joke.
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There is also the possibility that Enceladus' microbes use bioluminescence to survive. This ability is possessed by some types of terrestrial deep-sea and terrestrial organisms. It allows you to convert energy into the form of light. For organisms that may have to live several kilometers below the crust of Enetzelada, this may seem like a very suitable alternative.
Astronomers have figured out that Enceladus has all the basic ingredients necessary for the birth of life, so the most obvious further solution is to send a lander to the satellite, or even better - a mobile autonomous scientific station like Curiosity on Mars. NASA is already discussing such missions. Among them are, for example, Enceladus Life Finder (ELF). According to Manicelli, this project will allow us to study the satellite from different angles at once and ultimately determine whether there is life on Enceladus. Even in the form of microorganisms.
“An integrated approach is needed, not a search for life based on one or two biosignatures. There will be little sense from this. We have to consider all the possibilities of the environment and find out how these biosignatures appeared there,”explains Manicelli.
We may not eventually find bioluminescent whales hiding under the water and ice of Enceladus, but there is a possibility of finding something like our terrestrial tardigrades there. These crumbs are known to be able to survive almost anywhere.
“Tardigrades are truly amazing creatures. The presence of similar organisms on Enceladus is not a fantasy. This is one of the possibilities. These crumbs, however, are very tenacious,”says Manicelli.
NIKOLAY KHIZHNYAK