Where in the solar system to look for life?

In the title, the question is not “whether?”, but “where?”. So we're guessing that life is probably out there somewhere, which wasn't so obvious just a few decades ago. Where to go first and what missions should be allocated to relatively limited space budgets? After a recent discovery, voices have appeared in the atmosphere of Venus to aim our rockets and probes there, especially close to Earth.

1. DAVINCI mission - visualization

In February 2020, NASA awarded $XNUMX million to four project teams. Two of them are focused on mission preparation. Venus, one focuses on Jupiter's volcanic moon Io, and the fourth focuses on Neptune's moon Triton. These teams are the finalists of the qualification procedure NASA Discovery class mission. These are called small missions with an estimated budget of no more than $450 million, in addition to larger NASA missions. Of the four selected projects, a maximum of two will be fully funded. The money allocated to them will be used to develop the mission plan and concepts related to their mission within nine months.

One of the Venusian missions known as DAVINCHI + () provides, among other things, by sending a probe deep into the atmosphere of Venus (one). Although the search for life was not initially out of the question, who knows if the September revelations about a possible derivative of life, phosphine in the planet's clouds, will affect the mission plan. The mission to Triton involves the search for the underwater ocean, and the results of the study of Enceladus by the Cassini spacecraft always smell of traces of life.

last discovery in the clouds of Venus this fueled the imagination of researchers and desire, and so after the discoveries of recent years. So where are the other most promising places for extraterrestrial life? Where should you go? What caches of the System, besides the mentioned Venus, are worth exploring. Here are the most promising directions.

March

Mars is one of the most Earth-like worlds in the solar system. It has a 24,5-hour clock, polar ice caps that expand and contract with the seasons, and a large number of surface features that have been carved by flowing and stagnant water throughout the planet's history. Recent discovery of a deep lake (2) under south polar ice cap i methane in the Martian atmosphere (the content of which varies depending on the time of year and even the time of day) make Mars an even more interesting candidate.

2. Vision of water under the surface of Mars

methane this is important in this cocktail because it can be produced by biological processes. However, the source of methane on Mars is not yet known. Perhaps life on Mars was once in better conditions, given the evidence that the planet once had a much more favorable environment. Today, Mars has a very thin, dry atmosphere, almost entirely composed of carbon dioxide, which offers little protection from solar and cosmic radiation. If Mars managed to keep a little below the surface water reservesIt is possible that life could still exist there.

Europe

Galileo discovered Europe more than four hundred years ago, along with three other major the moons of Jupiter. It is slightly smaller than the Earth's Moon and revolves around the gas giant in a 3,5-day cycle at a distance of about 670. km (3). It is constantly being compressed and stretched by the gravitational fields of Jupiter and other moons. It is considered a geologically active world, much like Earth, because its rocky and metallic interior is heated by strong gravitational influences, keeping it partially molten.

3. Artistic vision of the surface of Europe

Europe Square it is a vast area of ​​water ice. Many scientists believe that below the frozen surface there is a layer of liquid water, a global ocean, which is warmed by its heat and can be more than 100 km deep. Evidence for the existence of this ocean, among other things, geysers an explosion through cracks in the ice surface, a weak magnetic field, and a chaotic surface pattern that could be deformed by rotation underneath ocean currents. This ice sheet insulates the subsurface ocean from extreme cold and space vacuumas well as from the radiation of Jupiter. You can imagine hydrothermal vents and volcanoes at the bottom of this ocean. On Earth, such features often support very rich and diverse ecosystems.

Enceladus

Like Europe, Enceladus is an ice-covered moon with a subsurface ocean of liquid water. Enceladus goes around Saturn and first came to the attention of scientists as a potentially habitable world after the discovery of huge geysers near the south pole of the moon.(4) These jets of water emerge from large cracks in the surface and splash across space. They are clear evidence underground liquid water storage.

4. Visualization of the interior of Enceladus

In these geysers, not only water was found, but also organic particles and small grains of stony silicate particles that occur during the physical contact of subsurface ocean water with the rocky ocean floor at a temperature of at least 90 ° C. This is very strong evidence for the existence of hydrothermal vents at the bottom of the ocean.

Titanium

Titan is Saturn's largest moon i the only moon in the solar system with a thick and dense atmosphere. It is shrouded in an orange haze made up of organic molecules. This was also observed in this atmosphere. weather systemin which methane appears to play a role similar to that of water on Earth. There are precipitation (5), periods of drought, and surface dunes created by the wind. Radar observations have revealed the presence of rivers and lakes of liquid methane and ethane, and possibly the presence of cryovolcanoes, volcanic formations that erupt liquid water rather than lava. This suggests that Titan, like Europa and Enceladus, has an underground reservoir of liquid water.. The atmosphere is composed primarily of nitrogen, which is an essential element in the building of proteins in all known life forms.

5. Vision of methane rain on Titan

At such a great distance from the Sun, Titan's surface temperature is far from comfortable -180˚C, so liquid water is out of the question. However, the chemicals available on Titan have raised speculation that there may be life forms with a chemical composition entirely different from the known chemistry of life. 

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