Meteor showers and cometary debris are kicking up lunar dust at rates much higher than initially assumed, producing towering clouds above the Moon’s surface. But what goes up must come down — meaning it’ll only be a matter of time before those iconic astronaut footprints will be gone forever.
Though we can’t see it from Earth, the Moon features a non-uniform layer of dust just slightly above its surface. These towering clouds are comprised of tiny particles of moon and space dust kicked-up by the endless onslaught of incoming space debris. Such are the findings of a new Nature study by a University of Colorado research team led by physicist Mihaly Horanyi.
Because the Moon lacks an atmosphere, every single object caught in its gravity well is guaranteed to strike its surface — including tiny bits of dust. As noted in the Los Angeles Times’ coverage of the new study, the moon encounters no less than five tons of space dust each day, creating mini-explosions that cause the lunar dust to rise up as much as 125 miles.
Above: Artist’s conception of the lunar dust and LADEE spacecraft trajectory. The colors represent the amount of material thrown up from the surface and the gray haze represents the dust cloud. (credit: Daniel Morgan and James Szalay)
“This is day in and day out,” Horanyi told the LA Times. “It is continuously ongoing. Every impact is just a little speck of dust being replaced, but eventually, this process will erase the footprints of the first astronauts to step on the moon.”
Horanyi gave no indication as to when the Apollo footprints might disappear, but his team’s work suggests they could be erased by gradual geological processes rather than via falling ejecta produced by and handful of large impacts.
Interestingly, the dust clouds are asymmetrical. From the LA Times:
The scientists explain that one side of the moon — what [study co-author James] Szalay calls “the front windshield” — is more likely to get hit by especially fast moving particles that come from comets. Because these particles are moving at extra high speeds, they cause more dust to be shot off the moon when they strike. That leads to a dust cloud that is more dense than on the “rear windshield” side of the moon.
The researchers now suspect that all airless bodies in the solar system have similar dust clouds, including the moons of Mars and Mercury.
Much more at the Los Angeles Times.