A combination of observation and computer simulations conducted by NASA is providing new clues how the moon got inked i.e. swirling pattern of light and dark found at over hundred locations across the planet surface.
According to John Keller, “these light and dark pattern are called Lunar swirls- they are unique as we have only seen these features on the moon and their origin remained a mystery until their discovery”.
Keller is project scientist for NASA’s Lunar Reconnaissance Orbiter (LRO) mission, which made the observations.
Keller said previous observation yielded two significant clues about their formation. First, they appear where ancient bits of the magnetic field are embedded in the lunar crust (although not every “fossil” magnetic field on the moon has a lunar swirl). Second, the bright areas in the eddies appear to be less weathered than their surroundings.
These two clues led to three prominent theories regarding the formation of swirls pattern. The swirls and the magnetic fields could both have formed from plumes of material ejected by comet impacts.
Alternatively, perhaps when fine dust particles get lofted by micrometeorite impacts, an existing magnetic field over the swirls sorts them according to their susceptibility to magnetism, forming light and dark patterns with different compositions.
Finally, since particles in the solar wind (electrons and ions) are electrically charged, they respond to magnetic forces. Perhaps the magnetic field shields the surface from weathering by the solar wind.
The research team of scientist created computer models that provide new insights into how the magnetic shield hypothesis could work.
The new models reveal that the magnetic field can create high electric fields when the solar wind attempts to go flow through. This would reduce the weathering from the sun wind, leaving brighter regions over protected areas.
The observation appears to provide support for the magnetic shield hypothesis, but don’t rule out the other ideas. “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 the ultraviolet and far ultraviolet light are consistent with earlier observations that indicate the swirls are less weathered than their surroundings,” said Keller.
The research was funded by the LRO mission and the DREAM-2 center. DREAM-2 is part of SSERVI at NASA’s Ames Research Center in California’s Silicon Valley.