A weird long cloud on Mars has returned. It's right on schedule, scientists say. - Space.com

A weird long cloud has formed so many times over the same Martian volcano that scientists have given up and named it.

Meet the Arsia Mons Elongated Cloud, or AMEC.

Its long bright trail has become a familiar feature over the peak known as Arsia Mons, to the southeast of the more famous Olympus Mons.

Although the cloud comes and goes over the volcano, scientists say it isn't formed by the volcano itself.

So far, scientists have caught the cloud clocking in as long as 1,100 miles (1,800 kilometers), according to ESA.

The tail-like structure is made of water ice, and despite its location over Arsia Mons, it isn't formed by the volcano itself, scientists said, but instead by the way local winds interact with the topography.

And the Arsia Mons Elongated Cloud doesn't just come, stick around for a while, then dissipate.

And the spacecraft's orbit lines up to put Arsia Mons in its view during the morning hours when the cloud is visible.

The scientists last spotted Arsia Mons' tail-like cloud in September and October 2018.