The Red Planet Has a Purple Side

When you picture Mars, the first thing that probably jumps to mind is that classic rusty, iron‑oxide hue – the sort of dusty red that’s earned the planet its nickname, the Red Planet. But the latest pictures from ESA’s Mars Express orbital camera show that, at least in one corner of the world, Mars can pull off a lavender‑purple makeover.

The scene comes from the south‑polar region, centered on a dramatic escarpment called Thyles Rupes. "Rupes" simply means cliff in Latin, and the name “Thyles” harks back to a mythical northern land spoken of by ancient travelers. This cliff tower soars more than a kilometre high, slicing through the landscape like a giant, frozen wall.

What gives this area its unexpected colour is a cocktail of fine Martian dust, seasonal frost and patches of carbon‑dioxide ice. In the early morning light, the fine dust is illuminated in a way that makes the reds shift toward pink, while the frost adds a cool blue‑white sheen. The two together blend into a soft, almost pastel purple that dominates the photograph.

Not all of the material here is the same. The darker, more saturated reds trace back to ancient volcanic eruptions that spewed mineral‑rich lava onto the surface. Those rocks are loaded with olivine and pyroxene – the same silicate minerals that dominate Earth’s mantle. Over time, wind has ground them down into the fine dust that now drifts across the pole.

Meanwhile, the lighter bluish‑white patches are layers of frozen carbon‑dioxide, or "dry ice," that persist year‑round near the pole. Even when spring rolls around, a seasonal frost cap of CO₂ expands over the southern ice cap, then retreats as temperatures rise, giving the region a constantly shifting appearance.

Zooming out, you can also spot a variety of dunes that look a bit out of place. The winds around the pole are fickle, so the dunes aren’t the sleek, rippled forms you see elsewhere on Mars. Instead, you get barchanoid ridges – those half‑moon sand piles that also dot Earth’s deserts, complete with twin “horns” that point down‑wind.

One of the more eye‑catching features in the wider view is Ultima Lingula, a plateau‑like formation about 550 km across. "Lingula" means "little tongue" in Latin, and the name fits the rounded, lobed shape that juts out of the icy terrain. Nearby, Burroughs crater (named after the sci‑fi writer Edgar Rice Burroughs) spans roughly 100 km, adding a touch of literary flair to the otherwise stark landscape.

How did Thyles Rupes get so tall in the first place? Unlike Earth, Mars doesn’t have active plate tectonics. The planet is essentially a single, stagnant lid, so the usual mountain‑building process we see on our own world doesn’t apply. Scientists think the escarpment formed early in Mars’ history, when the planet’s interior cooled and the crust contracted. That contraction forced sections of the crust upward, carving the massive cliff we see today.

Modern orbiters like Mars Express, equipped with high‑resolution stereo cameras, have opened a window onto these hidden corners of the Red Planet. Over the past two decades, the steady stream of images from both ESA and NASA’s Mars Reconnaissance Orbiter has reminded us that even a “dead” planet still has plenty of visual surprises – and plenty to teach us about the geological stories of rocky worlds.

So the next time you think of Mars, imagine not just a barren desert of rust, but also a place where dust and frost can collaborate to paint a fleeting purple sunrise over a cliff that’s older than most human history. It’s a reminder that planetary surfaces are never truly static; they’re always changing, sometimes in the most unexpected colours.