The Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft, part of NASA’s Mars Scout program, is making fascinating and unexpected discoveries in the upper atmosphere at Mars. In December, it photographed aurorae around the red planet, which were quickly nicknamed the “Christmas lights”.
And now researchers announced that MAVEN has found a “mysterious” cloud of dust around Mars, which was unexpected and remains unexplained. According to Laila Anderson of the University of Colorado’s Laboratory for Atmospherics and Space Physics (CU LASP), “If the dust originates from the atmosphere, this suggests we are missing some fundamental process in the Martian atmosphere.”
The dust cloud is at a height of 93 to 190 miles above the surface. It is very thin, denser at lower altitudes, and its origins are a mystery. It is also not clear if this is a temporary or permanent phenomenon, though it has been in place since MAVEN became operational.
The dust might originate on the moons of Mars, in the solar wind moving off the sun, or debris left behind by comets. It might also have just drifted up from the surface. As yet, researchers are unaware of any mechanisms by which the dust cloud could have been created from any of these sources.
In the days before December 25, MAVEN also recorded a bright ultraviolet auroral glow in the northern hemisphere of Mars. Like the aurorae on earth, these are produced by solar radiation striking atmospheric particles and making them glow. Unlike the earth, however, the aurorae on Mars reach down much lower into the atmosphere. This is because Mars lost its magnetic field billions of years ago, and has no barriers to solar radiation, which can strike deep into the atmosphere.
These discoveries were presented at the 46th Lunar and Planetary Science Conference in The Woodlands, Texas. The MAVEN mission was launched in November 2013, to explore the planet’s upper atmosphere and its interactions with solar radiation. The goal is to study Mars as a dynamic system, looking at its environment, climate, geology and potential for life with a view to human exploration in the not-too-distant future.
