Medium in size, without great atmospheric or geological spectacles, the main feature of Mars (apart, of course, from its proximity to Earth) is its color . But what produces it? A group of researchers led by researchers from the Higher Council for Scientific Research (CSIC), in which the University of Vigo and NASA have also collaborated, offer an answer.
According to experts in the journal Scientific Reports , the origin is possibly the intense oxidation that pyrite produces, in an atmosphere without oxygen . Because when dissolved, the microparticles of this mineral –formed almost in equal parts by iron and sulfur– would generate the precipitation of iron oxides and sulphates, with their typical red color .
“During its dissolution, pyrite, the most common iron disulfide (FeS2) on Earth, is capable of producing highly reactive substances , including hydrogen peroxide – commonly known as hydrogen peroxide – and a set of radicals very unstable free “, indicates Carolina Gil Lozano, CSIC researcher at the Madrid Astrobiology Center and main author of the study.
Their work therefore suggests that the dissolution of pyrite microparticles unleashes an oxidation power capable of functioning even in atmospheres lacking oxygen such as Mars .
To reach this conclusion, scientists have combined computational models and laboratory experiments . Specifically, they designed a reactor to record the formation and decomposition of the aforementioned substances in controlled atmospheres using spectrophotometry and sensors.
Gil Lozano explains the technical details of the chemical process that “blushes” the neighboring planet: “The data obtained suggest that the hydrogen peroxide generated by the surface of pyrite reacts with iron released during its dissolution through the so-called ‘reaction of Fenton ‘, forming a large amount of free radicals in solution . From these data, we build a kinetic model to analyze the evolution of the free radicals involved in the process . “
