For those of you determine off your 2020 bingo plug-in , do n’t care , this foreign , long , slight cloud that has appeared over Mars was n’t all unexpected . In fact , it turned up right on clip , although not to be outdone by this year ’s events , astronomers are uncertain if it is usually this telling .
“ We have been investigating this intriguing phenomenon and were await to see such a cloud form around now , ” said Jorge Hernandez - Bernal , a PhD candidate and lead author of an ongoing study on the mysterious phenomenon , in a European Space Agency ( ESA)statement .
“ This elongated cloud forms every martian twelvemonth during this time of year around the southern solstice , and repeat for 80 days or even more , following a rapid day-after-day cycle . However , we do n’t know yet if the cloud are always quite this impressive . ”
A recur feature , the peculiar cloud forms every year around the southern solstice , when the Sun is in the southernmost position in the Martian skies , like it is in December on Earth . Because a Martian sidereal day , or colloidal suspension , is an supernumerary 39 minutes and 35 second longer than Earth ’s , however , a year on the Red Planet endure 668 sols , or 687 days , making the season twice as recollective , which is why the swarm release up now .
The elongate swarm establishment can turn over 1,800 kilometers ( 1,120 miles ) in distance , and hovers above the 20 - kilometer - gamy ( 12.4 - mile ) Arsia Mons volcano , close to the satellite ’s equator . However , in spite of its location , it ’s not a volcanic plume or tie to any volcanic activity at all , but a cloud of water ice . It ’s cogitate the swarm stream forms due to the volcano ’s leeward side , the side that does n’t face the nothingness . These are called orographic or lee clouds , and just like on Earth , form in response to air being forcibly lifted up due to topographical feature , like a mountain or volcano .
The cloud pictured here was snapped on July 17 ( above ) and July 19 ( top ) by theVisual Monitoring Camera(VMC ) on ESA ’s Mars Express , which has been orbiting Mars for 16 class .
inquisitively , the cloud only seems to work in the other aurora , farm for around three hours , and then quickly disappears , repeating this daily cycle for around 80 day . Most spacecraft orbiting Mars observe it in the good afternoon , but the Mars Express ' highly elliptical range offers a dawn front - row keister to the atmospherical feature .
“ The extent of this huge cloud ca n’t be consider if your camera only has a narrow-minded field of persuasion , or if you ’re only keep in the afternoon,”explainedEleni Ravanis , who works on the VMC instrument as a Young Graduate Trainee for the Mars Express mission .
“ Luckily for Mars Express , the highly elliptical arena of the spacecraft , coupled with the wide field of view of the VMC legal instrument , countenance us take pictures treat a wide area of the satellite in the early forenoon . That means we can catch it ! ”
The squad has now call the cloud the Arsia Mons elongate Cloud , or AMEC , and is set to answer some of the interrogative it throws up every year : why does it only appear in the daybreak , why does it appear and disappear so speedily , and is it usually so impressive , or has it , like many other phenomena this year , look around and thought : 2020 , huh ? Hold my beer .
