This April 2018, image from the European Space Agency (ESA) Mars Express spacecraft shows one of several local small-scale dust storms on the red planet in recent months. It arrived before the particularly intense dust storm season that’s taking place on Mars now, as the planet nears its perihelion (closest point to the sun). ESA said:
A much-larger storm emerged further southwest at the end of May and developed into a global, planet-encircling dust storm within several weeks.
The intensity of this major event means very little light from the sun reaches the Martian surface, a situation extreme enough that NASA’s 15-year-old Opportunity rover has been unable to recharge its batteries and call home: it has been in hibernation mode since mid-June.
Dust storms on Mars occur regularly during the southern summer season when the planet is closer to the sun along its elliptical orbit. The enhanced solar illumination causes stronger temperature contrasts, with the resulting air movements more readily lifting dust particles from the surface – some of which measure up to about 0.01 mm in size.
Martian dust storms are very impressive, both visually like in this image and in terms of the intensity and duration of the rarer global events, but they are generally weaker compared to hurricanes on Earth. Mars has a much lower atmospheric pressure – less than one hundredth of Earth’s atmospheric pressure at the surface – and Martian storms have less than half the typical wind speeds of hurricanes on Earth.
ESA said its Mars Express spacecraft is also equipped with the Visual Monitoring Camera that captures daily images of the red planet. And it said the current dust storm on Mars is being monitored by five ESA and NASA orbiters, while NASA’s Curiosity rover has been observing it from the ground thanks to its nuclear-powered battery.
Bottom line: April 2018 image from ESA’s Mars Express showing one of several small-scale dust storms that preceded the major global dust storm happening on Mars now.
Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. "Being an EarthSky editor is like hosting a big global party for cool nature-lovers," she says.