CME: Coronal Mass Ejections Could Erode Lunar Surface

The moon and other planets could be severely affected by solar storms and the accompanying coronal mass ejections (CMEs) according to a research by NASA scientists.

The research, which is the first attempt to predict the effects of a CME on the moon, showed that that solar storms and CMEs can significantly remove large amount of materials from the lunar surface and cause atmospheric loss for other planets like Mars that are not protected by global magnetic field.

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

According researchers, CMEs are intense gusts of the normal solar wind with a diffuse stream of electrically conductive gas called plasma blown outward from the surface of the Sun into space. CME in its strong state 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.

Meanwhile, the moon has a little atmosphere, technically called an exosphere, is vulnerable to CME effects, thus the plasma from CMEs can impact the lunar surface. Atoms from the surface are ejected in a process called "sputtering," researchers said.

"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."

"Connecting various models together to mimic conditions during solar storms is a major goal of the DREAM project," says Farrell.

Scientists believe that NASA's Lunar Atmosphere And Dust Environment Explorer (LADEE), which is 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.

"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," said Farrell.

However, 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 (Northern and Southern Lights). Other planets like Mars, which does not have a magnetic field, and small bodies like asteroids, can also be severely affected by fast-streaming CME gas.

NASA will launch in late 2013 the Mars Atmosphere and Volatile Evolution (MAVEN) mission that will orbit the Red Planet to investigate exactly how solar activity, including CMEs, removes the atmosphere.