(ORDO NEWS) — When night falls on the dusty plains of Mars, something strange happens. High above the surface, the atmosphere begins to glow with ultraviolet light, sometimes pulsing.
This glow, first detected by the Mars Orbiter mission in 2005, is now well characterized – and its surprising behavior shows how the Martian atmosphere circulates and changes throughout the year.
Despite its thin and tenuous atmosphere, the atmosphere of Mars is surprisingly complex.
The night glow, in comparison with her, is not so mysterious. In fact, the same phenomenon – a night glow caused by a combination of nitrogen and oxygen, albeit in the near infrared wavelengths – has been observed on Venus.
However, it can tell us how Mars’ atmosphere circulates and changes with the seasons to better predict the weather on the Red Planet.
“If we’re going to send humans to Mars,” said scientist Zachariah Milby of the Atmospheric and Space Physics Laboratory at the University of Colorado in Boulder, “we need to understand what’s going on in the atmosphere of the Red Planet.”
The glow occurs when currents in the Martian atmosphere decrease and the temperature drops sharply. At this altitude, nitrogen and oxygen atoms (which were separated from CO2, O2, and N2 by sunlight during the day) combine to form nitric oxide, emitting small flashes of ultraviolet light; collectively, this phenomenon appears as a night glow.
The new observations come from NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) orbiter, which has been studying Mars in great detail since 2014.
Five times a day, MAVEN took detailed images of Mars using its ultraviolet spectrograph; thanks to these observations, scientists were able to track the movement of ultraviolet light for the first time.
Much to the team’s surprise, the atmosphere pulsates three times a night – but only in spring and autumn. At this time, a glow appears around the middle of the planet, which intensifies during the equinox periods.
At other times of the year, the glow is brightest over the polar region, where winter reigns, and at the solstice. There it appears in unexpected configurations – waves and spirals.
There are still a number of questions that need to be answered, but research is a step in properly understanding the complex behavior of Mars’ atmosphere.
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