For decades, hundreds of spacecraft have explored Mars, bringing back valuable data about its history and characteristics. Scientists have learned that landscapes of dried lakes and rivers on the surface of Mars indicate that liquid water once existed there. Space missions have also discovered ice deposits several kilometers below the surface of the planet's poles, while the Perseverance probe is expected to bring samples to Earth over the next decade to further deepen our knowledge of the "red planet."
But what causes the color red?
characteristic of Mars? Recent studies, published in the scientific journal Nature Communications, show that this color comes from iron oxides that contain small amounts of water. According to the researchers, this iron oxide — or “rust” — could have formed quickly in the presence of cold water, further evidence that Mars once had water on its surface.
A phenomenon known from Earth
Colin Wilson, a scientist at the European Space Agency, explains that the oxidation process on Mars is not that different from that on Earth. Although the atmosphere of Mars is extremely dry, the rust that forms there still has a significant water content. Observations by American and European probes show that the red dust covering the planet is spread by strong winds, and due to the lack of precipitation, this dust has never been washed away.
The importance of the study
Adomas Valantinas, the study's lead author, explains that the new results support the hypothesis that iron oxidation occurred billions of years ago, when Mars still had liquid water and perhaps oxygen from water or other sources. This may have happened around 3 billion years ago, a period when the planet was more Earth-like than it is today.
Although we have ample evidence of the presence of water in the past, its origin remains a mystery. Scientists hope that samples to be brought back from Mars to Earth will confirm these discoveries and provide more complete answers about the red planet's past. In the meantime, NASA is looking for faster and less expensive ways to carry out this historic mission.
