NASA's Astronomy Picture of the Day for November 2, 2026 features a 2018 image of the Arsia Mons Elongated Cloud on Mars, credited to ESA, DLR and FU Berlin, with processing and licensing by J. Cowart. According to the entry, the cloud was first recorded by NASA's Viking Orbiter 2 in 1977 and has since been imaged in greater detail by ESA's Mars Express spacecraft.

The cloud is described as forming only during spring and summer seasons and only during morning hours. It is made of water-ice, and the entry notes that the most familiar process causing cloud crystals to form around dust particles would fail given the thinness and lack of dust high in the Martian atmosphere. Leading speculation holds that dust is not involved. After forming near the volcano Arsia Mons, wind blows the cloud downstream, creating a tail that can extend over 1500 kilometers.

The entry says efforts to better understand the cloud will continue, and that such understanding may support a more complete view of cloud formation on Earth.