If you were to gaze carefully at Mars right now, stretched directly above the martian equator and high above the peak of the dormant volcano Arsia Mons, you would see a strangely long cloud covering large swathes of the sky. While it may look as though a volcanic eruption has occurred on the surface of Mars, this is quite impossible. So what could be causing this mysterious cloud?
As ScienceAlert reports, scientists have studied this cloud and believe they have an explanation as they have seen a similar kind of white cloud before. This vapor, which stretches for a full 930 miles, was first noticed recently after images were snapped on September 13 by the Mars Express orbiter.
Ever since that time, this white cloud has continued to be visible in the martian skies, changing slowly as weather conditions also change on Mars, and becoming so long and snake-like that even telescopes on Earth have been able to capture its ethereal whiteness against the deep red hues of the planet’s soil.
Even though it looks like the cloud may have been created by a volcano, scientists working at the European Space Agency have explained that this is nothing but an illusion. After all, volcanoes on Mars have been inactive, as far as we know, for millions of years, and the white cloud could never have emerged from the mouth of Arsia Mons. However, despite the fact that it didn’t come from a volcano, Arsia Mons is still believed to be the driving force behind it.
There's a Strange White Cloud Lingering Over Mars Right Now https://t.co/vtop4nDVFz
— ScienceAlert (@ScienceAlert) October 26, 2018
Meteorologists have announced that the cloud on Mars is what is known as an orographic cloud, which are frequently discovered when looking at the downward side of mountains. These special clouds are created from dense air after it has moved up hills and then expanded, after which it cools down significantly, letting moisture form upon tiny particles of dust.
In fact, scientists have said that while this time of year, clouds are frequently present above Arsia Mons, if you were to watch the Northern Hemisphere of Mars at the time of the winter solstice, these clouds would have long since disappeared. With clouds like this long white one appearing fairly regularly, scientists also note that every few years similar clouds can be spotted, and the Mars Express has also captured them in 2009, 2012, and 2015. As they do seem to show up every few years, it makes sense that in 2018 we would be seeing them again.
Given the pattern of the appearance of the white clouds, scientists are afforded an opportunity once again to study the density of particles in the atmosphere of Mars, and this exciting sighting may also allow researchers to learn more about the rise and fall of dust on the martian surface.