New NASA research may help explain 'lunar swirls'

GREENBELT, Md., May 2 (UPI) -- Scientists have been perplexed by "lunar swirls," or what some call the moon's "tattoos," but new research may help solve the mystery.

The markings known as lunar swirls are lighter in tone than their surroundings and appear both in groups and alone. The locations of the swirls correspond with portions of the moon's fossilized magnetic field, though some bits of ancient magnetic field exist without a tattoo present.

The swirls also appear to be less weathered than the surrounding lunar surface, which may explain the difference in color and tone.

Over the years, scientists have offered three main theories for the swirls' origins. First, researchers hypothesized that the swirls and magnetic fields were formed by material ejected by comets during impact.

Another theory is that existing magnetic fields governed the arrangement of materials stirred up by comet and asteroid impacts. It's also been suggested that the magnetic field protects the surface from weathering by solar winds' charged particles.

Some scientists have suggested the moon's buried magnetic field isn't strong enough to protect the surface from weathering, but new models based on observations by NASA's Lunar Reconnaissance Orbiter prove otherwise.

In a series of journal articles, NASA scientists describe the level of agreement between the new model's simulations and the three theories. The calculations suggest the magnetic field is significant enough to slow solar winds and protect the surface from weathering, which could explain the brighter swirls.

But the simulations don't rule out the other two theories.

"Until you have somebody making measurements on the lunar surface we may not get a definitive answer, but the new observations that analyze the swirls in ultraviolet and far-ultraviolet light are consistent with earlier observations that indicate the swirls are less weathered than their surroundings," John Keller, an LRO scientists at NASA's Goddard Space Flight Center, concluded in a news release.

Keller and his colleagues are continuing to study the interactions between lunar surface and different solar wind strengths and directions to better understand how weathering can alter the appearance the moon's surface.