WHAT’S BEING CLAIMED:
- An elongated white cloud, more than 930 miles long, has been stretched over Mars’ surface for over a month.
- The cloud is located near the red planet’s equator, over its volcano named Arsia Mons.
- The Martian winter season may be responsible for the cloud’s formation as similar clouds were spotted on Mars during the same time in previous years.
For more than a month, Mars’ red surface has been marked with a strange white cloud. It was first spotted by the Mars Express orbiter owned by the European Space Agency (ESA) back on September 13. Large enough to be seen by telescopes on Earth, the cloud stretches over 930 miles long. It hangs over the Martian volcano Arsia Mons which stands near the red planet’s equator.
The cloud looks similar to volcanic plumes that active volcanoes on Earth tend to produce. However, that’s probably not what it is because Arsia Mons is an extinct volcano. Its last eruption is estimated to have happened around 50 million years ago.
Even so, along with the seasons on Mars as well as the dust levels in the atmosphere, the volcano still plays a part in shaping the water-ice cloud because of its size. It dwarfs even the largest volcanoes on earth, standing 12 miles tall and has a diameter reaching almost 400 miles. When air passes over the volcano’s peak, it is cooled, producing an “orographic cloud” that forms over the downwind slopes- especially on the western side of the volcano.
It seems the winter season on the Martian planet is responsible for the cloud as similar plumes were observed during Mars’ winters in 2009, 2012, and 2015. The current cloud showed up just a few weeks before the Martian winter solstice which is on October 16. Dust storms that raged around the planet June and July probably contributed to the cloud’s size and visibility as well.