NASA | Ames Research Center | SSERVI | 2016 Mar 23
Did the “man in the moon” look different from ancient Earth?
[img3="This polar hydrogen map of the moon’s northern and southern hemispheres identifies the location of the moon’s ancient and present day poles. In the image, the lighter areas show higher concentrations of hydrogen and the darker areas show lower concentrations. (Credits: James Keane, University of Arizona; Richard Miller, University of Alabama at Huntsville)"]http://www.nasa.gov/sites/default/files ... _study.jpg[/img3][hr][/hr]New NASA-funded research provides evidence that the spin axis of Earth’s moon shifted by about five degrees roughly three billion years ago. The evidence of this motion is recorded in the distribution of ancient lunar ice, evidence of delivery of water to the early solar system. ...
Water ice can exist on Earth’s moon in areas of permanent shadow. If ice on the moon is exposed to direct sunlight it evaporates into space. Authors of the Nature article show evidence that a shift of the lunar spin axis billions of years ago enabled sunlight to creep into areas that were once shadowed and likely previously contained ice.
The researchers found that the ice that survived this shift effectively “paints” a path along which the axis moved. They matched the path with models predicting where the ice could remain stable and inferred the moon’s axis had moved by approximately five degrees. This is the first physical evidence that the moon underwent such a dramatic change in orientation and implies that much of the polar ice on the moon is billions of years old. ...
Lunar Polar Ice Reveals Tilting Axis of Earth’s Moon
NASA | Solar System Exploration Research Virtual Institute | 2016 Mar 23
Tales of a Tilting Moon Hidden in its Polar Ice
Planetary Science Institute | 2016 Mar 23
Lunar true polar wander inferred from polar hydrogen - M. A. Siegler et al
- Nature 531(7595):480 (24 Mar 2016) DOI: 10.1038/nature17166