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This new image is no exception. It focuses on the Tharsis region, which covers about one-quarter of the planet’s surface and is home to Mars’s famously colossal volcanoes. Many volcanoes can be seen here: Olympus, Arsia, Pavonis and Ascraeus Mons, and Jovis, Biblis and Ulysses Tholus. Olympus Mons is the largest, reaching nearly 22 km high (compared to Mount Everest’s 8.8 km here on Earth).
Canyons and clouds
Fascinating as they are, Mars’s volcanoes are far from the only interesting feature seen here. Excitingly, Mars Express has also captured an unexpected visitor in Mars’s largest moon, Phobos, which can be seen as a dark blob passing through to the lower left. Phobos sits very close to Mars by Solar System standards, orbiting just 6000 km from Mars's surface. For context, our own moon lies about 385 000 km away from Earth’s surface.
The fractured, fissured canyons of Noctis Labyrinthus – viewed several times before by Mars Express, including in a visualised fly-through – can also be seen below the trio of volcanoes slicing across the frame. The large landslide of Lycus Sulci can be spotted just north of Olympus Mons, as can the troughs and valleys of Tantalus Fossae to the upper right. These features have also been explored before by Mars Express.
Some fascinating weather features can be seen to the bottom of the frame, where a blue tinge creeps into this otherwise sand-hued scene. The colourful bands are clouds: a small, bright band of clouds to the right, and rippling ‘lee wave’ clouds to the left. Lee wave clouds arise when stacks of air flow over an obstacle on the terrain below, like a raised ridge, and receive a burst of speed in the process. The air then forms a wave-like feature on the sheltered (lee) side of the ridge.