An international team of astronomers studied clay samples found in the Martian Gale Crater and received “hints” that the Red Planet was once habitable.
The study is published in the journal Nature Astronomy and briefly covered by New Scientist. In their work, the authors write that at least some regions of Mars could have been inhabited for many thousands or even millions of years.
They came to this conclusion after analyzing clay samples taken in 2016 by the Curiosity rover in Gale Crater. Previous studies have proven that in ancient times this crater was a liquid lake, possibly with stable conditions favorable for life.
The Martian soil samples were taken by Curiosity using an airborne drill. As part of the new study, scientists analyzed them using X-rays, using other onboard instruments of the rover. As a result, they revealed the presence in the soil of a clay mineral associated with the so-called glauconite clays. According to the researchers, this indicates “the period of habitability in the past of the crater.”
“The conditions in which these minerals are formed are conducive to the presence of life,” says lead author Elisabeth Losa-Adams of the Spanish University of Vigo.
According to her, glauconite clays are a marker of habitability, but not evidence of the existence of life itself. Nevertheless, scientists called the presence of such mineral remains a promising sign. The very presence of such clays on Mars suggests that stable conditions suitable for life may have existed in Gale Crater for perhaps a million years.
Previous calculations showed that the lake in this crater could have formed about 3.5 billion years ago, when the atmosphere of the Red Planet was denser and able to hold liquid water on its surface.
It has existed for about 10 million years. Scientists have not yet found evidence that this lake had suitable living conditions, such as mild temperatures and neutral acidity. However, new research shows that the likelihood of this is quite high.
“The existence of glauconite clays could provide new insights into the evolution of the ancient lake in Gale Crater,” adds Losa-Adams.