Between satellites and prediction algorithms, forecasting Earth's weather can seem like a breeze. But when it comes to other planets, the lack of data and monitoring systems make predictions much more difficult. So over the years, scientists studying Mars have been gathering information gleaned from rovers, spacecraft and telescopes to study the Red Planet’s regular dust storms—and if their predictions are right, Mars is due for a big one.
Small dust storms are pretty common on Mars, though in real life they aren’t nearly as blustery as portrayed in movies like The Martian. Mars’ atmosphere is thin, so these storms are often about as forceful as a light breeze. Every few years, however, these normal storms whip up into massive weather systems that can envelope the red planet and are visible from Earth.
“It could be that it just takes a while for the sources to replenish themselves,” NASA planetary scientist Michael Smith says in a statement. “Maybe there’s some kind of cycle that the dust has to go through to get back into the right places to trigger a new one, or maybe it’s just kind of luck.”
As on Earth, Martian dust storms are triggered by the sun heating up the atmosphere, which causes air to rise, taking the dust along with it. Usually the large storms happen during Mars’ “summer” season, when the planet is closest to the sun. But until now, the global dust storms have been hard to predict, with the last truly big one taking place in 2007, Samantha Mathewson reports for Space.com. But NASA scientist James Shirley recently discovered evidence of another factor in Mars’ cycles of planet-wide dust storms: the Red Planet’s orbit.
In a study published in the journal Icarus, Shirley describes how Mars’ orbital momentum is slightly altered as it spins past other planets in the solar system. As it twirls around the sun, the Red Planet picks up and loses momentum periodically on a cycle of about every 2.2 Martian years (a little more than once every four Earth years). According to Shirley, the global dust storms tend to happen in years when Mars is gaining orbital momentum at the beginning of dust storm season.
"Mars will reach the midpoint of its current dust storm season on October 29th of this year,” Shirley says in a statement. “Based on the historical pattern we found, we believe it is very likely that a global dust storm will begin within a few weeks or months of this date."
Predicting a planet-wide dust storm would be big news for planetary scientists. Not only would it grant new insight into Martian meteorology, but it would be invaluable for planning future missions, both manned and unmanned. During the last global dust storm, NASA’s Spirit and Opportunity rovers were seriously deprived of solar power, but both luckily managed to survive. It could, however, mean a tricky touchdown for the European Space Agency’s Schiaparelli lander, which is due to arrive on the Red Planet in just a few days, Jonathan Amos reports for the BBC.
“We always knew we could arrive in a dust storm and Schiaparelli was designed with that possibility in mind,” ESA project scientist Jorge Vago tells Amos. “And from the point of view of getting data on the electrification of dusty atmospheres, it could be very nice.”
If the dust clouds do roll in, it could be a boon for future Martian explorers.