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| Image Credit : ESA/GCP/UPV/EHU Bilbao. |
Arsia Mons on Mars is one of the solar system's tallest
volcanoes, towering over two times Mount Everest, and the site of a strange
weather phenomenon. During the season, a long and large cloud of water ice can
be seen rising from the extinct volcano's summit. Scientists have now cracked
the code to its secrets.
The cloud is measured to be 1,800 kilometers (1,120 miles)
long and 150 kilometers (93 miles) wide, according to a report published in the
Journal of Geophysical Research. According to observations, the cloud is
orographic, forming as a result of the volcano.
Arsia Mons, at a height of 20 kilometers (63,360 feet), has
a major impact on the local weather. Even a world as barren as Mars has some
moisture in its atmosphere. This is directed up the volcanoes' flanks, where it
condenses into a cloud at higher and cooler altitudes.
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VMC observation of the Arsia Mons Cloud forming. Image Credit:
ESA/GCP/UPV/EHU Bilbao. |
For several months, this occurrence has happened every
morning. The cloud will begin to form just before sunrise and spread westward
at a speed of about 600 kilometers per hour (375 miles per hour) at an altitude
of 45 kilometers (27 miles). It detaches as it reaches its full length,
floating westward before evaporating in the afternoon.
Orographic clouds are normal on Earth, but they don't hit
such great lengths or have such vivid dynamics, according to co-author Agustin
Sánchez-Lavega of the University of the Basque Country. Understanding this
cloud gives us the exciting opportunity to use models to try to simulate the
cloud's formation, which will help us learn more about climatic environments on
Mars and Earth.
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| The creation, evolution, and demise of the Arsia Mons Cloud are depicted in this infographic. ESA provided this image. |
Sánchez-Lavega is the science lead for the VMC (Visual
Monitoring Camera), one of the instruments aboard the European Space Agency's
Mars Express mission. The instrument, dubbed "the Webcam," is a
low-resolution wide-field camera that was first used to confirm the separation
of Mars Express and the Beagle 2 lander in 2003 and is now being used for
public outreach.
The VMC, however, was recently reclassified as a science
camera, according to lead author Jorge Hernández Bernal, also of the University
of the Basque Country. It has a large field of view – important for seeing the
big picture at various local times of day – and is great for monitoring a
feature's evolution over time and in small time measures, despite its low
spatial resolution. As a result, we were able to analyze the entire cloud over
several life cycles.
VMC has now been able to describe how this cloud shapes,
shifts, and disappears, thanks to other instruments from Mars Express and
missions from NASA and the Indian Space Research Organization.
Read Original Article Here.
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