Mysterious giant Mars plume has astronomers looking for answers

16 Feb 2015

Illustration of Mars' atmosphere. Image via Wikimedia Commons

A mysterious giant plume erupting from the surface of Mars to a height of 250km is leaving scientists struggling to find answers in what is not the first recorded instance of such an event.

The recent findings of these plumes originates from images captured on two occasions between March and April 2012 that showed obvious plumes coming from the planet’s surface.

According to the European Space Agency (ESA), this recorded plume developed over a period of just under 10 hours and covered an area of 1,000km x 500km, remaining visible for about 10 days.

Unfortunately, none of the plant’s orbiting craft were able to get a close-up of the plume due to the viewing geometries and illumination conditions at that time.

What makes this particular plume so mysterious is its height which, based off previous recordings, reached over 150km higher than what would be expected because of the very thin division between the planet’s atmosphere and outer space which lead researcher on the analysis, Agustin Sanchez-Lavega, describes as “extremely unexpected”.

Observations of a mysterious plume-like feature (marked with yellow arrow) at the limb of the Red Planet on 20 March 2012. Image via W. Jaeschke

Sanchez-Lavega and his team searched through the database of Mars images captured by the Hubble Space Telescope between 1995 and 1999 as well as amateur photography between 2001 and 2014 but were unable to find any higher than 100km.

However, while they have yet to figure out what exactly could cause such a plume, Sanchez-Lavega said they have some theories.

“One idea we’ve discussed is that the features are caused by a reflective cloud of water-ice, carbon dioxide-ice or dust particles, but this would require exceptional deviations from standard atmospheric circulation models to explain cloud formations at such high altitudes,” he said.

The top image shows the location of the mysterious plume on Mars, identified within the yellow circle (top image, south is up), along with different views of the changing plume morphology taken by W. Jaeschke and D Parker on 21 March 21 2012. Image via W Jaeschke and D Parker

“Another idea is that they are related to an auroral emission, and indeed auroras have been previously observed at these locations, linked to a known region on the surface where there is a large anomaly in the crustal magnetic field.”

One potential aid in solving this mystery will come following the launch of the ESA’s ExoMars Trace Gas Orbiter in 2016 which will orbit the planet gathering vast quantities of data.

Colm Gorey was a senior journalist with Silicon Republic