Scientist are still trying to find out what’s the mysterious giant blob that appeared in the Martian atmosphere in 2012. First spotted on March 12, 2012, at that time it was rising from the southern hemisphere of the Red Planet, reaching 155 miles from the surface. Then the plume grew progressively, reaching over 600 miles across.

Scientists haven’t succeeded in offering any satisfactory explanations for this strange phenomenon yet. According to some descriptions, the haze was about 1,000 times stronger than the strongest aurora ever spotted. The strange plume also occurred in 1997 as well.

But it’s good to know that plumes are rather common traits of Mars’ atmosphere. The Red Planet’s atmosphere, which means that both ice and dust crystals can freely swirl up into the sky. Moreover aurorae are also likely to appear whenever charged particles interact with the magnetic field of the planet. This can also create a plume-like effect. However ice crystals are unlikely to climb above an altitude of 62 miles. Aurorae occur higher in the Martian sky, but no further than 80 miles, they fall short as well.

To cut a long story short, researchers led by Agustín Sánchez-Lavega of the University of the Basque Country in Bilbao, Spain came up with several theories meant to explain the baffling phenomenon.

So beside the plumes they also studied about 3,500 pictures of Mars, which had been captured by amateur astronomers from throughout the world from 2001 to 2014, and apart from these, scientist took a close look at a series of shots taken by the Hubble space telescope from 1995 to 1999, while it was getting close to the Red Planet.

However except for a single shot taken by the Hubble telescope on May 17, 1997, which shows a similar plume located in a similar spot, no other photographs show anything similar to have occurred.

“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,”

said Agustin Sanchez-Lavega.

As far as ice crystals are concerned, apart from the altitude problem, the atmosphere must also be much colder than it typically is at the plume’s height; moreover if the crystals were water ice, conditions must have been wetter than they get so far above ground. Ever.

Dust and aurorae theories have also been dissolved during the process.