Tuesday, December 6, 2011

CME's could 'sandblast' the Moon

Dust off: Images from computer simulations of the lunar calcium exosphere during a Coronal Mass Ejection (CME-left) and slow solar wind (SW-right) condition. Red and yellow indicate a relatively high abundance of calcium ions and blue, purple, and black indicate a low abundance. A CME produces a much denser exosphere than the slow solar wind. View movie of simulation HERE [NASA/Johns Hopkins-APL].
Bill Steigerwald

Solar storms and associated Coronal Mass Ejections (CMEs) can significantly erode the lunar surface according to a new set of computer simulations by NASA scientists. In addition to removing a surprisingly large amount of material from the lunar surface, this could be a major method of atmospheric loss for planets like Mars that are unprotected by a global magnetic field.

The research is being led by Rosemary Killen at NASA's Goddard Space Flight Center, Greenbelt, Md., as part of the Dynamic Response of the Environment At the Moon (DREAM) team within the NASA Lunar Science Institute.

CMEs are basically an intense gust of the normal solar wind, a diffuse stream of electrically conductive gas called plasma that's blown outward from the surface of the Sun into space. A strong CME may contain around a billion tons of plasma moving at up to a million miles per hour in a cloud many times the size of Earth.

The moon has just the barest wisp of an atmosphere, technically called an exosphere because it is so tenuous, which leaves it vulnerable to CME effects. The plasma from CMEs impacts the lunar surface, and atoms from the surface are ejected in a process called "sputtering."

"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," said William Farrell, DREAM team lead at NASA Goddard. "The model predicts 100 to 200 tons of lunar material – the equivalent of 10 dump truck loads – could be stripped off the lunar surface during the typical 2-day passage of a CME."

This is the first time researchers have attempted to predict the effects of a CME on the moon. "Connecting various models together to mimic conditions during solar storms is a major goal of the DREAM project," says Farrell.

Read the NASA/GSFC News Release, HERE.


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