A towering Martian dust devil has been imaged by the High Resolution Imaging Science Experiment (HiRISE) camera aboard NASA’s Mars Reconnaissance Orbiter.
The swirling column of dust was spotted on 14 March when it reached a height of around 20 kilometres, which is over twice the height of Mount Everest. However, despite its grandeur in height, the dust devil only spanned about 70 metres in width.
The spinning dust devil was seen by the Mars Reconnaissance Orbiter in the northern hemisphere of Mars, making its way along the Amazonis Planitia region.
When a spinning column of air sweeps up dust from the ground, it becomes visible as a dust devil. They are usually formed on a clear day, as opposed to the turbulent weather needed for a tornado to form. The Sun heats the ground and the air above it, which causes the heated air to rise rapidly into cooler air above it. If the conditions are just right, then the column of air will then start to rotate.
It is currently late spring in the northern hemisphere of Mars, and the summer solstice took place just two weeks after the image was taken. This is thus the time of the year when the ground gets most strongly heated by the Sun, and dust devils are likely to occur.
A dust devil occurring on an alien planet does not make it an alien phenomenon. Dust devils are a common feature on our own planet, although the larger ones typically only reach one kilometre in height.
The Mars Reconnaissance Orbiter was launched on 12 August 2005, and entered Martian orbit in March 2006. It has since amassed over 21,700 images taken with the HiRISE camera, which can be viewed by the public. Each picture covers several square kilometres, and the camera can resolve objects the size of a desk.
The Mars Reconnaissance Orbiter has a wealth of scientific instruments, and it is now in the extended phase of its mission. It is currently attempting to procure data on the red planet’s ancient environment, as well as how winds, meteorites, and frost influence the surface in the present day.
The HiRISE camera is opeated by the University of Arizona. The Mars Reconnaissance Orbiter, which was built by Lockheed Martin Space Systems, is managed by NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology (Caltech).