NASA’s Mars rover Curiosity has spotted a dust devil swirling through the parched Red Planet landscape. Curiosity photographed the dust devil on Aug. 9, capturing a spectral feature dancing along the border between dark and light slopes inside Mars’ 96-mile-wide (154 kilometres) Gale Crater. It’s no surprise that these dry whirlwinds, which we also get here on Earth, are cropping up inside the crater these days, Curiosity team members said. “It’s almost summer in Gale Crater, which puts us in a period of strong surface heating that lasts from early spring through mid-summer,” Claire Newman, an atmospheric scientist at the Arizona-based company Aeolis Research, wrote in a mission update on Wednesday (Aug. 26). (Gale lies about 4.5 degrees south of the Martian equator.)
“Stronger surface heating tends to produce stronger convection and convective vortices, which consist of fast winds whipping around low pressure cores,” Newman wrote. “If those vortices are strong enough, they can raise dust from the surface and become visible as ‘dust devils’ that we can image with our cameras.” Dust devils are typically quite faint, so Curiosity photos often must be processed before the features are visible, Newman added. But the Aug. 9 whirlwind showed up even in the raw, unprocessed rover imagery.