The European Space Agency’s (ESA) use of its satellites and the ExoMars Trace Gas Orbiter (TGO) sensor on a Mars exploration mission has led to an exciting and unexpected discovery. It was observed for the first time that the atmosphere of Mars glows green in the visible light spectrum during the night.
This effect is known as airglow, a phenomenon that also occurs on Earth, but is slightly different from the northern lights known as the aurora borealis. On Earth, nightglow is created when two oxygen atoms react to form the ozone molecule, while aurora borealis glow occurs when charged particles from the Sun collide with the Earth’s magnetic field.
It has been thought for about 40 years that there is airglow on Mars, and it was first detected a decade ago by the European Space Agency’s Mars Express spacecraft, which detected the phenomenon in the infrared. In 2020, this phenomenon was also observed in visible light using TGO during the day.
These new observations are interesting, especially for future missions to Mars. The airglow in Mars’ polar regions is very intense, which means simple and relatively inexpensive instruments cannot be used to study it.
Night airglow research on Mars is planned to continue as part of the TGO mission, as it will provide an excellent way to study the composition and dynamics of the planet’s upper atmosphere between 40 and 80 kilometers of altitude. Our better understanding of the Martian atmosphere could also contribute to the design of future missions to the Red Planet, by building satellites that can withstand atmospheric drag or designing parachutes that help reduce payloads on the surface of Mars.
Frequently asked questions:
What is nighttime airglow on Mars?
Nighttime airglow is a phenomenon that occurs in the Martian atmosphere when two oxygen atoms react to form an ozone molecule at an altitude of about 31 miles (50 km) from the planet’s surface.
Are there similar phenomena on Earth?
Yes, similar phenomena exist on Earth such as the northern lights known as the aurora borealis. However, Mars’ nocturnal airglow is slightly different from the aurora in composition and causes.
What is the importance of studying airglow on Mars?
Studying airglow helps understand the processes occurring in the Martian atmosphere, and provides insight for scientists in designing future missions to the Red Planet, including building satellites capable of dealing with different weather conditions and designing parachutes that help lower payloads to the surface of Mars.
