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December 2016 - A Bright Christmas
Report #22 - November 2016
The Revelation of Mars' Atmosphere
Thanks to NASA's Maven (Mars Atmosphere and Volitile Evolution) Mission, the answer explaining how Mars has evolved from such a luscious, warm planet to that of a red, deserted one has finally been discovered. Through analyzing MAVEN's data, scientists were able to conclude that Mars Atmosphere's current rate of gas loss to space increases significantly during solar storms. Without a thick atmosphere, basic necessities for life, such as water, cannot be maintained on a planet, hence why Mars, with its currently very thin atmosphere, cannot house life and is not the Earth-like planet it used to be.
An artist's impression of Mars' "Transformation" from its former luscious, Earth-like conditions to the desolate red planet it is today.
An artist's impression of the solar wind as it strips Mars of gas particles.
According to measurments from MAVEN, a solar wind strips gas from Mars at a rate of about 100 grams (1/4 pound) per second. This may seem like a low number, however, overtime, this loss of gas builds up. To make matters worse, scientists have observed that a series of solar storms have ambushed Mars in 2015. The sum of increased rate of gas loss during these storms and the frequent appearence of them is the recipe to the drastic thinning of Mars' astmosphere and change of the planet's climate.
What Is A Solar Wind?
NASA's definition of a solar wind is "a stream of particles, mainly protons and electrons, flowing from the sun's atmosphere at a speed of about one million miles per hour."
How Does A Solar Wind Strip Mars' Atmosphere?
An electric field, generated from the magnetic field carried by the solar wind as it rushes past Mars, accelerates electrically charged gas atoms (ions) and sends them flying out of Mars' upper atmosphere into space. Without these ions, gases in Mars' atmosphere, such as oxygen and nitrogen, disappear from the planet. Mars loses most of its ions (about 75%) from the "tail" region of the planet, or where the solar winds flow behind Mars. 25% of escaped ions come from the "polar plume" region of Mars, or above the planet's poles. A small fraction of lost ions also come from the extended cloud of gas that engulfs the red planet.
Why Is Earth's Atmosphere Still Intact?
One may question how come Earth's atmosphere is not thinning into space like Mars' and why our planet is not like the current red planet. The answer is all thanks to Earth's global magnetic field, which deflects the stream of protons and electrons that rush from the sun's atmosphere during a solar storm, keeping the Earth's gas ions intact and from shooting off into space. Unfortunately, Mars does not have this important defensive shield, or gobal magnetic field, when a solar storm hits, leaving the poor planet's upper atmosphere vulnerable to the one-million-miles-per-hour stream of particles.
An artist's impression of the intereaction between the solar wind and two inner planets, Mars and Earth, during a solar storm.
Mars vs. Solar Wind (left): As the solar wind hits Mars, without a global magentic field, gas particles from the planet's atmosphere are thrown out into space.
Earth vs. Solar Wind (right): As the solar wind approaches Earth, the planet's global magentic field deflects the it before it can make contact with Earth and knock its particles into Space.
SOURCES:
NASA's Scientific Visualization Studio and the MAVEN Science Team
http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=12046
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