Solar Storms Could Significantly Erode Lunar Surface

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According to a new set of computer simulations by NASA scientists Solar storms and associated Coronal Mass Ejections (CMEs) can significantly erode the lunar surface. 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. 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.” According to William Farrell, DREAM team lead at NASA Goddard they 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, 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. The researchers believe that NASA‘s Lunar Atmosphere And Dust Environment Explorer (LADEE) , a lunar orbiter mission scheduled to launch in 2013, will be able to test their predictions. The strong sputtering effect should kick lunar surface atoms to LADEE’s orbital altitude, around 20 to 50 kilometers (about 12.4 to 31 miles), so the spacecraft will see them increase in abundance. The moon is not the only heavenly body affected by the dense CME driver gas. Space scientists have long been aware that these solar storms dramatically affect the Earth’s magnetic field and are responsible for intense aurora.