If we walked on the surface of Mars at night, the stars would not be the main characters of our walk. The European Space Agency’s (ESA) ExoMars Trace Gas Orbiter (TGO) mission has discovered a mesmerizing green glow reflecting off the Martian night sky. According to its researchers, The phenomenon could become so bright that it would be visible to the human eye.
Something similar should have happened on the Red Planet, but until now it had never been directly observed. Green skies on Mars occur when two oxygen atoms combine to form one oxygen molecule about 50 km above the surface.
These oxygen atoms form on the dayside of Mars when sunlight breaks down carbon dioxide molecules. Then they go to the other side of the planet where it is night. They stop worrying about the Sun, they regroup and that’s it: a magical green glow at the lowest altitudes.
ESA says this would be equivalent to seeing lunar clouds on Earth. “These observations are unexpected and interesting for future trips to the Red Planet.”says Jean-Claude Gerard, lead author of a new study published this week in the journal Nature Astronomy.
Clues hiding behind the green skies of Mars
The green skies of Mars were discovered thanks to monitoring carried out by the TGO mission orbiting 400 kilometers from the planet. For this case, he used the ultraviolet-visible channel of his NOMAD instrument. This instrument covers the spectral range from near ultraviolet to red light. The team conducting this operation sent TGO to the edge of the planet to better observe the upper atmosphere.
The light that can be seen does not remain anecdotal. The night glow provides clues to atmospheric processes on Mars. It can provide information about the composition and dynamics of a difficult-to-measure region of the atmosphere. Also about the oxygen density on the red planet.
In its statement, ESA explained that views of Mars’ skies can also reveal how sunlight and solar wind – the stream of charged particles emanating from our star – release energy. All this is invaluable data for future space missions. For example, the density of the atmosphere directly affects the drag experienced by orbiting satellites and parachutes used to deliver probes to the surface of Mars.
Martian green sky and northern lights
They are similar, but not. The Northern Lights are another phenomenon that illuminates the atmospheres of planets. And they have been recorded both on Earth and on Mars. Their formation varies: auroras occur when energetic electrons from the Sun collide with the upper atmosphere. Moreover, they vary in space and time, and the green glow of the night sky of Mars is more uniform.
Earth also detects a green glow similar to that of Mars, only it is so faint that it cannot be observed with the naked eye. Both night lights and auroras can have a wide range of colors, depending on which atmospheric gases are most abundant at different altitudes.
Source: Hiper Textual
