Once upon a time, Mars could be a real paradise for organic life: seas splashed on its surface, a dense atmosphere protected the planet from the fall of asteroids, and a warm climate contributed to the development of life. This did not last long: as a result of a catastrophe that we had not yet studied, the planet’s atmosphere suddenly became thinner, the magnetic field went blank, and the seas and oceans of our cosmic neighbor either evaporated or went deep beneath its surface. All that remains of the day of a grand catastrophe of planetary proportions – rusty sand, stones and various rocky debris – does not at all resemble what the fourth planet was in ancient times. Hoping to find the remains of bacteria that may have inhabited Mars before the mysterious deadly event, scientists over and over again sent a large number of various missions to this deserted world, but attempts to search for them have remained futile for a long time. Or is it still not?
Organic matter discovered on Mars
Gale Crater on Mars is an unusual place. Its diameter is as much as 154 kilometers, and the walls of this object are covered with sedimentary rocks, which once could fill the crater completely. Although the nature of these sediments has not yet been fully studied, there is a high degree of probability that once upon a time the crater was a rather large lake in whose waters life could be hidden. A new analysis of organic molecules found in the dried Martian mud of Gale Crater has once again shown that the hypothesis described above may be true. So, particles found in this unusual place may be of biological origin, the portal sciencealert.com claims.
Although our understanding of Martian molecules is limited and incomplete, the information that we already have may be compatible with the life that existed on the Red Planet billions of years ago. When the molecules were removed by the Curiosity rover from a clay section called the Murray Formation, their preliminary analysis revealed the presence of a group of aromatic compounds called thiophenes in them. On Earth, these compounds are commonly found in crude oil, consisting of superheated dead organisms such as zooplankton and algae, as well as in coal from dead plants. It is believed that such a formation appears in an abiotic way – that is, through a physical process, for example, when sulfur reacts with organic hydrocarbons at temperatures above 120 degrees Celsius. Although this reaction can occur without the participation of living organisms, both hydrocarbons and sulfur can be of biological origin. In order to identify the origin of the detected substance, scientists from Washington State University decided to use the pyrolysis method to analyze the detected thiophenes.
There are several ways in which thiophenes could appear on Mars without the need for the presence of life. So, they could arise during volcanic activity or some other geological processes that can produce heat. In addition, particles were discovered by us earlier in space wanderers – meteorites. However, there is something very interesting in Martian thiophenes: all the geological processes described above require that sulfur be nucleophilic, i.e. capable of giving electrons to its partner by reaction. However, most of the sulfur on Mars exists in the form of non-nucleophilic sulfates, which most often appear during biological intervention.
So it is quite possible that once a very long time, long before the appearance of humanity and even dinosaurs on Earth, Mars could boast of the existence of bacterial colonies that produced thiophenes. Then, when Mars dried up, thiophenes were petrified, but were found by us several billion years later.
In order to verify the data obtained by the Curiosity rover, Roscosmos and the European Space Agency plan to send a new rosalind Franklin rover to the Red Planet, which is scheduled for launch in July 2020. It is known that the device will have on board a highly sensitive device capable of detecting and analyzing any thiophenes. If the data of the rover confirm the information previously obtained by us, the scientific world can expect a real revolution to search for past or present life on other planets of the solar system.