BOULDER, Colo., June 17 (UPI) -- New data collected by NASA's LADEE mission confirms the presence of a large, lopsided dust cloud surrounding the moon.
Scientists say the cloud is created by the impacts of tiny interstellar particles and debris left behind by comets and asteroids. As each of these larger dust particles strike the lunar surface, thousands of smaller dust specks are disturbed and sent flying into the airless space around Earth's moon.
Dust clouds on the moons of Jupiter and Saturn have previously been identified, but this is the first time a dust cloud has been confirmed on the moon.
"Identifying this permanent dust cloud engulfing the moon was a nice gift from this mission," lead study author Mihaly Horanyi, a professor of astrophysics at the University of Colorado, said in a press release. "We can carry these findings over to studies of other airless planetary objects like the moons of other planets and asteroids."
Horanyi leads the team of scientists in charge of LADEE's dust-detection instrument known as LDEX.
Because cometary dust streams through space in a counterclockwise orbit around the sun -- opposite Earth's path -- the particles mostly strike the lunar surface head-on, creating a dust cloud that is normally thickest at the protruding front end.
"The Earth/moon system orbits the sun with an average speed of 67,000 miles per hour, and like bugs on a car windshield, the interplanetary micrometeoroid materials smack into the 'upstream' side of the Earth and moon," Rick Elphic, a LADEE project scientist who didn't participate in the recent study, told Mashable.
"On Earth these cause meteors, which burn up in the atmosphere, but with the almost negligible atmosphere on the moon, these particles smash right into the lunar surface with tremendous speed."
During meteor showers, when the Earth and moon cross paths with the debris-dense tails of comets and asteroids, the dust cloud surrounding the moon spikes in thickness and density.
Scientists are excited by the new discovery, but it doesn't help solve the ongoing mystery of the dusty glow reported by astronauts on the Apollo missions of the 1960s and 70s.
Astronauts observed an odd glow along the horizon just before sunrise on the moon, leading scientists to hypothesize about the presence of a dust cloud. But the latest findings don't mesh with those early observations.
"The cloud we identified is comprised of bigger particles and their density is so low that this cloud could not have been noticed by the astronauts," said Horanyi.
The new research was published this week in the journal Nature.