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article imageSolar storm can strip a planet of its atmosphere, says NASA study

By JohnThomas Didymus     Dec 7, 2011 in Science
A NASA study says that solar storms and Coronal Mass Ejections (CMEs) can erode the surface of a body and also strip it of its atmosphere. The study says CMEs might have caused loss of atmosphere by some planets unprotected by magnetic field.
CMEs are massive bursts of solar wind, plasma and magnetic fields rising above the solar corona and released into space. They are often associated with other forms of solar activity, including solar flares.
Science Daily says that a strong CME could contain about a billion tons of plasma traveling in a cloud many times the size of the Earth, at up to a million miles per hour.
The research led by Rosemary Killen at NASA's Goddard Space Flight Center, Greenbelt, Md., says our moon has a very sparse atmosphere called an exosphere, and it is very vulnerable to CME activity. When a plasma from a CME impacts on lunar surface, atoms from the surface of the moon are ejected in a process scientists call "sputtering."
The research team says their study, published in the Journal of Geophysical Research Planets, is the first attempt at studying the impact of CMEs on the lunar surface. According to William Farrell, leader of the team at NASA's Goddard Space Flight Center,
"We found that when this massive cloud of plasma strikes the moon, it acts like a sandblaster and easily removes volatile material from the surface. The model predicts 100 to 200 tons of lunar material could be stripped off the lunar surface during the typical 2-day passage of a CME."
According to Killen,
"'Sputtering' is among the top five processes that create the moon's exosphere under normal solar conditions, but our model predicts that during a CME, it becomes the dominant method by far, with up to 50 times the yield of the other methods,"
The study explained that CMEs are able to strip the lunar surface because they are denser and faster than ordinary solar wind and also because, in contrast to solar winds which consist mostly of light hydrogen ions or protons, they are rich in highly charged heavy ions. Heavier helium ions have a greater electric charge than protons and can "sputter" tens of times more atoms from the lunar surface.
Dana Hurley of the John Hopkins University's Applied Physics Laboratory in Laurel, Md., and co-author of the research paper, said:
"The computer models isolate the contributions from sputtering and other processes. Comparing model predictions through a range of solar wind conditions allows us to predict the conditions when sputtering should dominate over the other processes. Those predictions can later be compared to data during a solar storm."
The researchers are hoping that NASA's Lunar Atmosphere and Dust Environment Explorer (LADEE) scheduled for launch in 2013 will be able to test predictions of their work. The "sputtering" effect is predicted to raise atoms on the lunar surface to 20 to 50 kilometers altitude where LADEE would be able to detect them. Farell says:
"This huge CME sputtering effect will make LADEE almost like a surface mineralogy explorer, not because LADEE is on the surface, but because during solar storms surface atoms are blasted up to LADEE."
Could a CME end the world in 2012?
The NASA researchers say the moon is not the only body that may be affected by CMEs. CMEs can also have significant effect on the Earth's atmosphere and its magnetic field. CMEs, according to scientists, are responsible for intense aurora, the so-called Northern and Southern Lights.
Aurora Borealis. - United States Air Force photo by Senior Airman Joshua Strang
Aurora Borealis. - United States Air Force photo by Senior Airman Joshua Strang
To illustrate the potential effect of CMEs on a planet, the researchers say that Mars might have had an atmosphere in the past that was eroded by CMEs. Mars, unlike the Earth, does not have a magnetic field that surrounds the entire planet. CMEs may therefore sputter and erode the planet's upper atmosphere. NASA says it plans to launch in 2013 the Mars Atmosphere and Volatile Evolution (MAVEN) mission that will orbit Mars and investigate how solar activity may remove a planet's atmosphere.
Is our planet Earth adequately protected by its magnetic field from the sputtering effect?
Digital Journal recently reported that NASA officials released a statement in November 10 that denied doomsday predictions that the world will end in a massive solar flare or a CME in 2012. The NASA statement which said such solar flares are physical impossibility, explained:
"...some people worry that a gigantic 'killer solar flare' could hurl enough energy to destroy Earth. Citing the accurate fact that solar activity is currently ramping up in its standard 11-year cycle, there are those who believe that 2012 could be coincident with such a flare..."
The NASA statement denied the doomsday scenario, saying:
"...it there simply isn't enough energy in the sun to send a killer fireball 93 million miles to destroy Earth."
NASA said that while solar flares cannot literally "end the world," a massive flare could have significant effect on the Earth. The statement said:
"Solar flares, for instance, affect Earth's upper atmosphere and may disrupt satellite communication systems. Another form of the sun's activity called coronal mass ejections (CMEs) may have more dramatic effect. A CME, according to NASA, could disrupt GPS signals and radio communications. But not even the most powerful CME can bring about the end of the world, NASA assures everyone."
More about Solar storms, lunar surface, Coronal mass ejection, NASA
 
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