NASA’s Perseverance rover recently took nighttime images of a rock outcrop on Mars called the Malgosa Crest abrasion patch using its SHERLOC WATSON camera.
The images revealed unexpected green-hued spots within the predominantly red Martian rock. The largest green spot was about 2 mm in diameter.
On Earth, similar green spots in red rocks can indicate the past presence of liquid water. When water interacts with iron in the rock, it can change the oxidation state of the iron and turn it green.
The green color suggests the rock experienced chemical changes from water before solidifying. Microbes are sometimes involved on Earth, but not necessarily on Mars. Other chemical reactions like those involving sulfur could also cause the greening.
Perseverance was unable to use its arm-mounted instruments to analyze the green spots directly. Identifying the responsible chemical process remains a mystery for now.
The discovery of these enigmatic green features within Mars’ typically red rocks adds to the evidence the rover is finding regarding the planet’s wet past and the potential for ancient microbial life.
Source: Space
