The enigma behind the moon’s swirling patterns of light and dark found scattered across the surface of our natural satellite may have been answered through observations and computer simulations.
The patterns, which have also been called the moon’s “tattoos,” have been observed throughout the lunar surface. “These patterns, called ‘lunar swirls,’ appear almost painted on the surface of the moon,” John Keller, of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, said. “They are unique; we’ve only seen these features on the moon, and their origin has remained a mystery since their discovery.”
The observations, made by NASA’s Lunar Reconnaissance Orbiter (LRO), revealed that these lunar swirls can stretch up to miles, and that they can either occur in groups or be isolated. Previous studies directed to understand the formation of these swirls have revealed that they are observed in areas where magnetic field can be found in the lunar crust. There are several factors – including solar wind and microscopic winds, according to NASA – that can cause the darkening of the material exposed to space.
According to the new findings, areas that are bright in the swirls have been less weathered. A definite magnetic field can cause the formation of an electric field when the solar wind flows through. This electric field, comprising of hundreds of volts, causes the slowing of the solar wind, limiting the weathering and resulting in more bright spots.
While the new study has shown support for the protection of the weathering as a result of the magnetic field, there still are other ideas and hypotheses to consider.
“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,” Keller said.
Funded by the LRO mission and the DREAM-2 Center, the new models were published in three papers – in Icarus by lead author Andrew Poppe of the University of California at Berkeley on March 1, 2016; in the Journal of Geophysical Research: Space Physics by lead author Shahab Fatemi of University of California, Berkeley on June 18, 2015; and in the Journal of Geophysical Research: Planets by lead author Michael Zimmerman of The Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland on November 25, 2015.
The research was funded by the LRO mission and the DREAM-2 center.