Why is Mars red? These research may reveal the secret of the planet's past

The atmosphere of Mars is too cold for liquid water on its surface. However, thanks to many space missions, we have premises that the planet was full of billions of years ago. This is evidenced, for example, by formations reminiscent of dried lakes or rivers, as well as minerals, which can still be found on the surface of the red planet.

The latest research, the results of which were published on Tuesday in the scientific journal “Nature Communications” suggest that it is one of the minerals that may be responsible for the coloring of Martian dust. It is ferrihydrite or using the chemical – metastable hydrated oxygen iron (III). It occurs in the form of small molecules, on Earth it is found in soil and ground waters, where it can play a role in storage of iron, as well as water purification or biological reactions.

This discovery gives another, very important clue that reveals a scrap of secrets of the geological past of Mars. Ferrihydrite arises in the presence of water and a temperature lower than other potential minerals (such as hematite), which were previously taken into account for the cause of the planet's color. This, according to scientists, can confirm that the red planet was able to keep the water in a liquid state billions of years ago.

– The question is why Mars is red, he has been considered for hundreds, if not thousands of years – said the main author of the study Adam Valantinas from the Brown University in Providence in the American state of Rhode Island. – Based on our analysis, we believe that ferrihydrite is everywhere in dust, and probably in rock formations. We are not the first to consider ferrihydrite to be the cause of Mars's color, but now we can test it better using observation data and innovative laboratory methods to basically recreate Martian dust in the laboratory – he added.

– These discoveries indicate that in the past Mars could be suitable for living. They also emphasize the value of coordinated research NASA and its international partners during the exploration of fundamental issues regarding our solar system and the future of exploration space – said Geronimo Villanueva from the NASA Space Flight Center Goddard, Maryland, who co -founded the study.

Work results are the result of data analysis of a lot of Martian missions and orbital observations of many devices. First, research instruments on orbiters and rover provided detailed information regarding the surface of the planet. Then they were compared with laboratory experiments, in which the team tested how the light affects the ferrihydrite particles or other minerals in simulated Martian conditions.

“We want to understand the ancient atmosphere of Mars and his chemical processes – also those present,” explained Valantinas. – There are questions about whether life has ever existed there. To understand this, you need to know the conditions that prevailed during the formation of this mineral. The study gave us evidence indicating the formation of ferrihydrite, and we know that in order for this to happen, there must have to be conditions in which oxygen from the air or other sources and water could react with iron. These conditions were very different from today's dry, cold environment. When the Martian wind spread this dust everywhere, he created the iconic red look of the planet, he said.

The team will have a chance to test their hypotheses as soon as there are samples of the Martian surface, taken by the Perseverance rover.

– Mars is still a red planet. Just our understanding of why it is actually red, it has been transformed – summed up Valantinas.