NASA officials said Wednesday that a massive solar winds could displace large portions of the moon’s topsoil.
Solar storms remove a surprisingly large amount of material from the lunar surface, according to computer simulations conducted by the space agency over the past year.
NASA said Tuesday that “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.”
Scientists said strong solar mass ejections were to blame for the potential hazard posed to the moon. Such ejections can contain around a billion tons of plasma – electrically charged particles – moving at up to a million miles per hour in a cloud many times the size of Earth. The moon, which lacks an atmosphere to protect it, suffers disproportionately when particles ejected by the solar storms impact the surface.
“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. 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,” explained official William Farrell. “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.”
Plasma is created when energetic events, like intense heat or radiation, remove electrons from the atoms in a gas, turning the atoms into electrically charged particles called ions. The Sun is so hot that the gas is emitted in the form of free ions and electrons called the solar wind plasma. Ejection of atoms from a surface or an atmosphere by plasma ions is called sputtering.
The study is the first to explain the effect of solar mass ejections on the surface of the moon. NASA officials likened the impact of the solar storms on the moon to a “sandblaster,” warning that significant layers of soil on the moon would be shifted and disturbed. NASA estimated that upwards of 100 to 200 tons of moon soil could be striped off of the surface.
“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 NASA’s William Farrell.
NASA officials also noted that the moon is the not the only celestial body at risk of losing its topsoil. Mars is also reportedly at risk as well. With very little of the Red Planet covered with a magnetic field, a fast traveling burst of energy in the direction of Mars would have a similar sandblasting effect.
The team used data from satellite observations that revealed this enrichment as input to their model. For example, helium ions comprise about four percent of the normal solar wind, but observations reveal that during a CME, they can increase to over 20 percent. When this enrichment is combined with the increased density and velocity of a CME, the highly charged, heavy ions in CMEs can sputter 50 times more material than protons in the normal solar wind.