NASA Says Moon Spin Axis Shifted By 5-Degrees 3 Billion Years Ago

NASA has discovered evidence via research that it funded that indicates eons ago the surface of the moon might have looked different from Earth. According to the research the spin axis of the moon shifted by about 5-degrees around 3 billion years ago. Evidence of this movement was found in how ancient lunar ice is distributed seen as evidence of water delivered to the early solar system.

"The same face of the moon has not always pointed towards Earth," said Matthew Siegler of the Planetary Science Institute in Tucson, Arizona, lead author of a paper in today's journal Nature. "As the axis moved, so did the face of the 'man in the moon.' He sort of turned his nose up at the Earth."

Water ice lives on the moon in areas that are in permanent shadow and can be billions of years old and the authors of research that will be published in an issue of Nature claim that the shift of the lunar axis over time has allowed sun to creep into previously shadowed areas and melt that ancient water ice on some parts of the moon. Researchers found that the ice left behind that wasn't touched by the sunlight as the axis tiled paints a clear picture of how the axis moved.

Researchers discovered that ice concentrations at each pole were displaced by the same distance, but in exactly opposite directions suggesting the spin axis had changed from what we know today. Scientists say that planetary bodies can shift their axis when a large change in mass distribution occurs. In looking for evidence of this large mass change, the only feature that could match direction and amount of axis change is the Procellarum region on the lunar near-side. The scientists say that concentrations of radioactive material in the Procellarum region are high enough to have heated a portion of the lunar mantle and cause a density change significant enough to reorient the moon.

SOURCE: NASA