When mysterious plumes were observed high in the Martian atmosphere by amateur astronomers back in 2012, explanations ranged from massive auroras to a meteor impact. Now it seems that a wild bout of space weather may be to blame for the phenomena.
Clouds on Mars are aregular occurrence, but the majority form relatively lowin the planet's atmosphere, whereas the freak plumes detected in 2012 wereobserved over 250 km (155 miles) above the barren Martian surface.
This altitude puts the plumes in the ionosphere, where the electrically charged solar wind comes into contact with the atmosphere. This suggests that some disturbance of the plasma in the region could beat least partially responsible for the plumes.
Nospacecraft were orbiting in a favorable position to directly observethe 2012 phenomenon. However, a wealth of data on Mars' plasma andsolar wind environment harvested by ESA's Mars Express spacecraftprovided evidence that a significant coronal mass ejection (CME) striking the Martianatmosphere at the correct time and place could account for the plume.
It is theorized thatthe interference caused by the CME may have stirred up the atmosphereof the Red Planet, causing ionospheric plasma and magnetic fields tobuffet high altitude ice dust grains, drawing them into theionosphere as the plasma escaped into space.
At this point there isnot enough evidence conclusively say space weather is afactor in plume creation. There have also been numerousobservations of CME emissions striking the Martian ionosphere thatdid not result in a plume, though this could be the result ofunfortunate viewing conditions between Earth and Mars rather than anabsence of the features.
If it were discoveredthat space weather is indeed a factor, the discovery could informcurrent theories regarding how the Red Planet shed the majority ofits atmosphere to space. Planetary scientists believe that Mars oncehosted an atmosphere thick enough to maintain liquid water, in an environment that may have once been hospitable to microbial life.
Source: ESA
