NASA Captures Leaping Lunar Dust in Moon Images

Earth's moon seems like a lifeless, dead place at first glance. It's cold, inhospitable and possesses little in the way of an atmosphere. Yet our moon may be more active than we at first thought. New research shows that lunar dust leaps over the moon's surface, partially propelled by the solar wind that streams through space.

The research, led by Michael Collier at NASA's Goddard Space Flight Center, noted that electrically charged lunar dust near shadowed craters was lofted above the surface of the moon and bounced back and forth between the sunlit areas on opposite sides. The phenomenon itself is an indicator of unusual surface electrical fields. In the shaded regions, the surface is negatively charged in comparison to the sunlit regions. This creates a complex, larger electric field which causes the dust to leap between regions.

The scientists first observed the phenomenon through Surveyor images. A type of twilight was seen over the landed platforms during dusk and dawn--a surprising image since the moon does not have an atmosphere that's dense enough to scatter light. In the end, the scientists concluded that the image was caused by swarming dust overtop a large number of shaded regions.

The dust itself jumps when solar wind, a thin stream of electrically conducting gas called plasma blown off of the sun at around a million miles per hour, hits the moon. The combination of the solar wind and sunlight knocks negatively charged electrons off of the surface, which gives it a positive charge. On the unlit side of the moon, electrons from the solar wind rush in and give the surface a negative charge.

While the reason for the jumping motion is clear, scientists are still unsure how the dust is launched above the lunar surface in the first place. It's possible that impacts from small meteoroids could help propel the dust into the thin atmosphere, or localized concentrations of electric fields could lift the dust electrostatically from the surface.

The researchers aren't done studying this phenomenon yet, though. They plan to examine how complications will affect the path of a dust particle on the moon and around asteroids. In addition, they hope look at Apollo-era images to evaluate possible evidence of dust canopies over shadowed craters.