A mysteriously long, thin cloud appeared again on the Arsia Mons volcano 20 km above Mars.
A recurring feature, the cloud is made of water ice, but despite the appearances it is not a plume associated with volcanic activity. Instead, the current forms as the airflow is influenced by the slope of the volcano ”; the leeward ” – the side that does not face the wind.
These cloud images, which can reach up to 1800-km in length, were taken on July 17 and 19 by the Visual Monitoring Camera (VMC) on Mars Express, which has been studying the planet Red from orbit for the last 16 years. .
“We have been investigating this intriguing phenomenon and have been waiting to see a cloud shape right now,” explains Jorge Hernandez-Bernal, Ph.D. candidate at the University of the Basque Country (Spain) and lead author of the ongoing study.
“This elongated cloud forms a Martian year during this season around the southern solstice, and repeats for 80 days or even longer, after a fast daily cycle. However, we still don’t know if the clouds are always so impressive “.
A Martian day, or sol, is slightly longer than an Earth day in 24 hours, 39 minutes and 35 seconds. A year on the Red Planet consists of 668 sol, about 687 days, so the seasons last twice as long.
The southern solstice is the time of year when the Sun is at its southernmost position in the Martian skies, the same as December 21 on Earth. In the early morning during this period, this flying cloud grows for about three hours, quickly disappearing again a few hours later.
Many spacecraft in orbit around the Red Planet tend to observe in the afternoon, however Mars Express is in a prime position to gather and provide crucial information about this unique effect.
“The extension of this huge cloud can’t be seen if your camera has only a narrow field of view, or if you only observe in the afternoon,” says Eleni Ravanis, a Young Graduate apprentice for the Mars Express mission that works specifically for the VMC instrument.
“Fortunately for Mars Express, the spacecraft’s highly elliptical orbit, combined with the wide field of the VMC instrument, allows us to take photos covering a wide area of the planet early in the morning. That means we can capture it!”
The Mars Express science team has now named the cloud the Arsia Mons Elongated Cloud, AMEC. So, how long has it been disappearing and reappearing? Why only form early in the morning? Stay up to date as scientists continue to investigate, revealing more mysteries from Mars.
Mars Express keeps an eye on curious clouds
Provided by the European Space Agency
Citation: Extremely prolonged cloud return to Mars (2020, 30 July) achieved on 30 July 2020 from https://phys.org/news/2020-07-extremely-elongated-cloud-mars. html
This document is subject to copyright. Apart from any fair business for the purpose of private study or research, no part may be reproduced without written permission. The content is provided for information purposes only.