A Long Cloud on Mars
What’s causing this unusually long cloud on Mars? Known as the Arsia Mons Elongated Cloud (AMEC) and first recorded by NASA’s Viking Orbiter 2 in 1977, the strange cloud has been imaged in greater detail more recently by ESA’s robotic Mars Express spacecraft. The featured image is from 2018. The cloud forms only during spring and summer seasons and then only during morning hours. Made of water-ice, the most familiar process that causes cloud crystals to form around bits of dust would fail due to the thinness and lack of dust high in the Martian atmosphere. Leading speculation holds that dust is not involved. After the cloud forms near the volcano Arsia Mons, wind blows the cloud downstream — creating a tail that can extend over 1500 kilometers. Efforts to better understand AMECs will continue, an understanding that may bolster a more complete view of cloud formation on Earth.
As the Chief Exoplanet & Cosmic Astrophysicist Narrator, I present your cosmic connection: High above the rusted, dust-swept plains of Mars, a solitary, elongated cloud drifts through a thin atmosphere, a fleeting reminder of the delicate balance required to sustain a planetary veil. This fragile atmospheric dance finds a distant, chilling echo in the realm of GJ 357 d, a super-Earth located 9.44 parsecs away that teeters on the edge of habitability within its star's temperate zone. While the Martian cloud is a transient whisper of water vapor, the thick atmosphere of GJ 357 d holds the profound, frozen potential to trap enough warmth to transform its sub-zero 220K surface into a cradle for liquid water.