A long, thin cloud was spotted by the Visual Monitoring Camera attached to Mars Express, a satellite that’s been orbiting Mars since 2004. The appearance of the cloud isn’t a surprise to scientists, as it is a recurrent feature on the planet. The cloud is composed of water ice, as Gizmodo detailed:
The cloud is a recurrent feature on Mars, appearing annually above Arsia Mons, a 12.4-mile-high (20-kilometer) volcano located near the Martian equator. The cloud resembles a volcanic plume, but it’s not associated with any kind of volcanic activity. Composed of water ice, the cloud arises along the volcano’s leeward slope, that is, the side not facing the prevailing winds.
The Arsia Mons Elongated Cloud, or AMEC, as it’s called, can reach about 1,110 miles (1,800 km) in length. Incredibly, it can get big enough to be spotted by telescopes on Earth, according to the ESA.
image via Gizmodo