Looking for aliens on Mars. If there was life, maybe it survived?

Mars has everything necessary for life to exist. Analysis of meteorites from Mars shows that there are substances under the surface of the planet that can support life, at least in the form of microorganisms. In some places, terrestrial microbes also live in similar conditions.

Recently, researchers at Brown University have studied chemical composition of Martian meteorites - pieces of rock that were thrown from Mars and ended up on Earth. The analysis showed that these rocks can come into contact with water. produce chemical energywhich allows microorganisms to live, as at great depths on Earth.

Studied meteorites they may, according to scientists, constitute a representative sample for a large part crust of marsthis means that a significant part of the planet's interior is suitable for life support. “Important findings for the scientific study of layers below the surface are that wherever there is groundwater on Marsthere is a good chance of accessing enough chemical energyto sustain microbial life,” said Jesse Tarnas, head of the research team, in a press release.

Over the past few decades, it has been discovered on Earth that many organisms live deep under the surface and, deprived of access to light, draw their energy from the products of chemical reactions that occur when water comes into contact with rocks. One of these reactions is radiolysis. This happens when radioactive elements in the rock cause the water molecules to split into hydrogen and oxygen. The released hydrogen dissolves in the water present in the area and some minerals such as Pyrites absorb oxygen to form sulfur.

they can absorb hydrogen dissolved in water and use it as a fuel by reacting with oxygen from sulfates. For example, in Canadian Kidd Creek Mine (1) These types of microbes have been found nearly two kilometers deep in water where the sun hasn't penetrated in over a billion years.

1. Boston Dynamics robot explores the mine

Kidd Creek

W Martian meteorite researchers have found substances necessary for radiolysis in quantities sufficient to sustain life. so the ancient wreckage sites have remained largely intact until now.

Earlier studies indicated traces of active groundwater systems on the planet. There is also a significant possibility that such systems still exist today. One recent study showed, for example, the possibility of an underground lake under the ice sheet. So far, subsoil exploration will be more difficult than exploration, but, according to the authors of the article, this is not a task that we cannot cope with.

Chemical clues

In 1976 year NASA Viking 1 (2) landed on the Chryse Planitia plain. It became the first lander to successfully land on Mars. “The first clues came when we received photos of the Viking showing carving marks on Earth, usually due to rain,” he said. Alexander Hayes, director of the Cornell Center for Astrophysics and Planetary Science, in an interview with Inverse. “He has long been present on Mars liquid waterwho carved the surface and he filled the craters, forming lakes».

Vikings 1 and 2 they had small astrobiological "laboratories" on board to carry out their exploratory experiments. traces of life on Mars. The Tagged Ejection experiment involved mixing small samples of Martian soil with drops of water containing a nutrient solution and some Activated carbon study the gaseous substances that can form living organisms on Mars.

Study of soil sample showed signs of metabolismbut scientists disagreed as to whether this result was a sure sign that there was life on Mars, because the gas could have been produced by something other than life. For example, it can also activate the soil by creating gas. Another experiment conducted by the Viking mission looked for traces of organic material and found nothing. Forty years later, scientists treat these initial experiments with skepticism.

In December 1984 V. Allan Hills A piece of Mars has been found in Antarctica. , weighed about four pounds and was likely from Mars before an ancient collision lifted it from the surface. red planet to earth.

In 1996, a group of scientists looked inside a meteorite fragment and made an amazing discovery. Inside the meteorite, they found structures similar to those that could be formed by microbes (3) well found the presence of organic materials. Initial claims of life on Mars have not been widely accepted as scientists have found other ways to interpret the structures inside the meteorite, arguing that the presence of organic material may have caused contamination from materials from Earth.

3. Micrograph of a Martian meteorite

Tue 2008 lazy spirit stumbled upon a strange shape protruding from the Martian surface in the Gusev crater. The structure is called "cauliflower" because of its shape (4). Such on Earth silica formation associated with microbial activity. Some people quickly assumed that they were formed by Martian bacteria. However, they could also be formed by non-biological processes such as wind erosion.

Nearly a decade later, owned by NASA Lasik Curiosity discovered traces of sulfur, nitrogen, oxygen, phosphorus and carbon (vital ingredients) while drilling into Martian rock. The rover also found sulfates and sulfides that could have been used as food for microbes on Mars billions of years ago.

Scientists believe that primitive forms of microbes may have found enough energy to eats martian rocks. The minerals also indicated the chemical composition of the water itself before it evaporated from Mars. According to Hayes, it is safe for people to drink.

4Martian 'cauliflower' photographed

Spirit rover

In 2018, Curiosity also found additional evidence the presence of methane in the Martian atmosphere. This confirmed earlier observations of trace amounts of methane by both orbiters and rovers. On Earth, methane is considered a biosignature and sign of life. Gaseous methane does not last long after production.breaking down into other molecules. Research results show that the amount of methane on Mars increases and decreases depending on the season. This led scientists to believe even more that methane is produced by living organisms on Mars. Others, however, believe that methane can be produced on Mars using as yet unknown inorganic chemistry.

In May of this year, NASA announced, based on the analysis of Sample Analysis at Mars (SAM) data, portable chemistry lab aboard Curiositythat organic salts are likely present on Mars, which may provide further clues to this Red Planet once there was life.

According to a publication on the subject in the Journal of Geophysical Research: Planets, organic salts such as iron, calcium, and magnesium oxalates and acetates may be abundant in surface sediments on Mars. These salts are the chemical residue of organic compounds. Planned European Space Agency ExoMars rover, which is equipped with the ability to drill to a depth of about two meters, will be equipped with a so-called Goddard's instrumentwho will analyze the chemistry of the deeper layers of the Martian soil and perhaps learn more about these organic substances.

The new rover is equipped with equipment to search for traces of life

Since the 70s, and over time and missions, more and more evidence has shown that Mars could have had life in its early historywhen the planet was a humid, warm world. However, so far, none of the discoveries has provided convincing evidence of the existence of Martian life, either in the past or in the present.

Starting in February 2021, scientists want to find these hypothetical early signs of life. Unlike its predecessor, the Curiosity rover with the MSL laboratory on board, it is equipped to search for and find such traces.

Perseverance stings the crater of the lake, about 40 km wide and 500 meters deep, is a crater located in a basin north of the Martian equator. Jezero Crater once contained a lake estimated to have dried out between 3,5 and 3,8 billion years ago, making it an ideal environment to look for traces of ancient microorganisms that could have lived in the lake's waters. Perseverance will not only study Martian rocks, but also collect rock samples and store them for a future mission to return to Earth, where they will be examined in the laboratory.

5. Visualization of SuperCam operation aboard the Perseverance rover.

Hunting for biosignatures deals with the rover's array of cameras and other tools, especially the Mastcam-Z (located on the rover's mast), which can zoom in to explore scientifically interesting targets.

The mission science team can put the instrument into operation. supercam persistence directing the laser beam at the target of interest (5), which creates a small cloud of volatile material, the chemical composition of which can be analyzed. If these data are promising, the control group may give the researcher an order. rover robotic armconduct in-depth research. The arm is equipped with, among other things, a PIXL (Planetary Instrument for X-Ray Lithochemistry), which uses a relatively strong X-ray beam to look for potential chemical traces of life.

Another tool called SHERLOCK (scanning habitable environments using Raman scattering and luminescence for organic and chemical substances), is equipped with its own laser and can detect the concentrations of organic molecules and minerals that form in the aquatic environment. Together, SHERLOCK i PIXEL They are expected to provide high-resolution maps of elements, minerals and particles in Martian rocks and sediments, allowing astrobiologists to assess their composition and identify the most promising samples to collect.

NASA is now taking a different approach to finding microbes than before. Unlike download vikingPerseverance will not look for chemical signs of metabolism. Instead, it will hover over the surface of Mars in search of deposits. They may contain already dead organisms, so metabolism is out of the question, but their chemical composition can tell us a lot about past life in this place. Samples collected by Perseverance they need to be collected and returned to Earth for a future mission. Their analysis will be carried out in ground laboratories. Therefore, it is assumed that the final proof of the existence of former Martians will appear on Earth.

Scientists hope to find a surface feature on Mars that cannot be explained by anything other than the existence of ancient microbial life. One of these imaginary formations might be something like stromatolite.

On the ground, stromatolite (6) rock mounds formed by microorganisms along ancient coastlines and in other environments where there was a lot of energy for metabolism and water.

Most of the water did not go into space

We have not yet confirmed the existence of life in the deep past of Mars, but we are still wondering what could have caused its extinction (if life really disappeared, and did not go deep under the surface, for example). The basis of life, at least as we know it, is water. Estimated early mars it could contain so much liquid water that it would cover its entire surface with a layer from 100 to 1500 m thick. Today, however, Mars is more like a dry desert.and scientists are still trying to figure out what caused these changes.

Scientists try, for example, to explain how did mars lose waterthat was on its surface billions of years ago. For most of the time, it was thought that much of Mars' ancient water had escaped through its atmosphere and into space. Around the same time, Mars was about to lose its planetary magnetic field, shielding its atmosphere from a jet of particles emanating from the Sun. After the magnetic field was lost due to the action of the Sun, the Martian atmosphere began to disappear.and the water disappeared with it. Much of the lost water could have been trapped in rocks in the planet's crust, according to a relatively new NASA study.

Scientists analyzed a set of data collected during the study of Mars over many years, and based on them, however, they came to the conclusion that release of water from the atmosphere in space, it is responsible only for the partial disappearance of water from the Martian environment. Their calculations show that much of the water currently in short supply is bound to minerals in the planet's crust. The results of these analyzes were presented Evie Sheller from Caltech and her team at the 52nd Planetary and Lunar Science Conference (LPSC). An article summarizing the results of this work was published in the journal Nauka.

In studies, special attention was paid to sexual intercourse. deuterium content (heavier isotope of hydrogen) into hydrogen. Deuter occurs naturally in water at about 0,02 percent. against the presence of "normal" hydrogen. Ordinary hydrogen, due to its lower atomic mass, is easier to get out of the atmosphere into space. The increased ratio of deuterium to hydrogen indirectly tells us what was the speed of the exit of water from Mars into space.

The scientists concluded that the observed ratio of deuterium to hydrogen and the geological evidence for water abundance in the Martian past indicate that the planet's water loss could not have occurred solely as a result of atmospheric escape in the Martian past. space. Therefore, a mechanism has been proposed that links the release to the atmosphere with the capture of some water in the rocks. By acting on rocks, water allows clay and other hydrated minerals to form. The same process takes place on Earth.

However, on our planet, the activity of tectonic plates leads to the fact that the old fragments of the earth's crust with hydrated minerals are melted into the mantle, and then the resulting water is thrown back into the atmosphere as a result of volcanic processes. On Mars without tectonic plates, the retention of water in the earth's crust is an irreversible process.

Inner Martian Lake District

We started with underground life and will return to it at the end. Scientists believe that its ideal habitat in Martian conditions reservoirs could be hidden deep under layers of soil and ice. Two years ago, planetary scientists announced the discovery of a large lake salt water under ice at the South Pole of Marswhich was met with enthusiasm on the one hand, but also with some skepticism.

However, in 2020, researchers once again confirmed the existence of this lake and they found three more. The discoveries, reported in the journal Nature Astronomy, were made using radar data from the Mars Express spacecraft. “We identified the same water reservoir that was discovered earlier, but we also found three other water reservoirs around the main reservoir,” said planetary scientist Elena Pettinelli from the University of Rome, who is one of the co-authors of the study. "It's a complex system." The lakes are spread over an area of ​​about 75 thousand square kilometers. This is an area about one-fifth the size of Germany. The largest central lake has a diameter of 30 kilometers and is surrounded by three smaller lakes, each several kilometers wide.

7. Visualization of Martian underground reservoirs

in subglacial lakes, for example in Antarctica. However, the amount of salt present in Martian conditions can be a problem. It is believed that underground lakes on mars (7) must have a high salt content so that the water can remain liquid. Heat from the depths of Mars can act deep below the surface, but this alone, scientists say, is not enough to melt the ice. “From a thermal point of view, this water must be very salty,” says Pettinelli. Lakes with about five times the salt content of seawater can support life, but when the concentration approaches XNUMX times the salinity of seawater, life does not exist.

If we can finally find it life on mars and if DNA studies show that Martian organisms are related to Earth ones, this discovery could revolutionize our view of the origin of life in general, shifting our view from a purely terrestrial to a terrestrial one. If studies showed that Martian aliens have nothing to do with our lives and evolved completely independently, this would also mean a revolution. This suggests that life in space is common as it originated independently on the first planet near Earth.