The Red planet is windier than we thought. The movement of “megaripples” in Martian desert sands reveals that powerful winds do occur, and that Mars has a more dynamic atmosphere than previously assumed.
Megaripples are features of deserts on both Earth and Mars. These larger waveforms (up to tens of metres across) have courser grains of sand at their crest and migrate more slowly than their smaller cousins, requiring stronger winds to shift the larger sand grains.
Until recently scientists had considered the megaripples on Mars to be stationary – a relic of Mars’s more geologically active past. But high resolution images gathered by the Mars Reconnaissance Orbiter since 2006, show Martian megaripples moving up to 1.2m over five Martian years – just over twice as fast as our hair grows.
The atmosphere on Mars is 100 times less dense than Earth’s and many had assumed that this thin atmosphere would make it impossible to whip up winds capable of moving the hefty sand grains that sit at the crest of megaripples. However, the latest findings (published in the Journal of Geophysical Research: Planets) record the stately march of massive Martian megaripples (up to 35m apart), opening up new questions about the weather on Mars.
