by NASAs Perseverance robber is approaching four years of activity on the surface of Mars – and all the while the rover has been exploring ancient environments, collecting samples and investigating whether our reddish neighbor ever supported microbial life
In his latest findingsUsing the SHERLOC WATSON camera, Perseverance captured a nighttime mosaic image of the Malgosa Crest scour site, at a location called the “Serpentine Rapids.” The image revealed white, black and, surprisingly, greenish spots in the rock. Although the composition of these rocks remains a mystery, the unexpected find has scientists excited about what other hidden gems Perseverance might encounter in the future.
To obtain images from within the rock, Perseverance scoured a rock outcrop called “Wallace Butte.” The abrasion was five centimeters (about two inches) in diameter, and the large green spot seen in the upper left of the image was about two millimeters (about 0.08 inches) in diameter. The image was acquired on August 19, Mars Day 1243 Mars Mission 2020.
Rocks on Earth that resemble the studied red rocks of Mars typically get their color from oxidized iron, the same type of iron that makes our blood red and is similar to the oxidized red rust you find on your car. The green spots seen in Perseverance’s new image are also common in red rocks on Earth, forming when liquid water seeps through sediment before hardening into rock. This process supports a chemical reaction that converts oxidized iron to its reduced form, creating a green hue in the rock.
Related: The Perseverance rover will get a beautiful view of Mars’ large crater from a smooth slope
Microbes sometimes play a role in this process on Earth, but decaying organic material can also create the right conditions for the reduction reaction. Chemical interaction between sulfur and iron can also facilitate iron reduction reactions without the help of microorganisms.
Exactly what type of reaction was responsible for the green spots in Perseverance’s image will remain a mystery, however, as there was not enough room for the rover to safely place its arms on the green spot while holding the SHERLOC and PIXL instruments . Thus, the robotic explorer was denied a closer look. The team hopes that Perseverance will unearth something similar in the future to better understand what types of chemical reactions cause these features in the rock.
Next on the agenda for Perseverance is to ascend to the Jezero crater rimduring which time it will have to cover steep terrain. Then it will finally leave the crater it has called home for the past two years.
