Mars dust storms bury the whole planet

Once or twice a Martian decade, a single dust storm grows large enough to swallow the entire planet. Every crater, every polar cap, every rover — wrapped in the same red haze for months.

Nothing on Earth comes close. Our biggest cyclones are continental; Mars's *global* dust storms are planetary, and they have no obvious off switch. The 2018 storm killed NASA's Opportunity rover after fifteen years of operation by blocking enough sunlight to starve its solar panels.

The mechanism is brutally simple. Mars has almost no liquid water, no vegetation, and a surface coated in fine, easily lifted dust. When sunlight warms a patch of ground, the thin atmosphere heats and rises. Heated dust absorbs more sunlight, which heats the air further, which lifts more dust. On Earth, rain and oceans damp this loop within hours. On Mars, nothing stops it, and a local plume can balloon to cover 165 million square kilometres — every surface on the planet, all at once.

The storms eventually fade as the dust settles out of the still-thin air. Until then, the entire world is inside the weather.