Detecting the green light produced when the sun's rays interact with oxygen atoms in Earth's atmosphere is relatively easy. Millions of plants provide this element in sufficient quantities to cause phenomena such as the polar auroras or the green streak visible, mainly at night, from space. However, locating a similar phenomenon on other planets was, until now, a theoretical approach that did not fit with experimental measurements. A modification of the orientation of the NOMAD instrument, on board the TGO- missionExoMars, from the European and Russian space agencies, has managed to detect, for the first time, the green streak on Mars. This finding, published in Nature Astronomy, allows us to devise formulas to identify sources of oxygen in other celestial bodies and more precisely analyze the density and composition of the atmosphere, something essential for future missions that plan to land on the red planet.
