By understanding how and where the poles have shifted, researchers could learn how much frozen water has been transformed from solid ice straight into gas — a process called sublimation.
An extreme shift in the lunar poles' locations — especially toward warmer, less shadowy regions of the moon — would have resulted in water being quickly sublimated and lost to space, also giving new water less time to accumulate at the poles. .
"Based on the Moon's cratering history, polar wander appears to have been moderate enough for water near the poles to have remained in the shadows and enjoyed stable conditions over billions of years," Vishnu Viswanathan, a research scientist at NASA Goddard who led the study on the moon's wandering poles, said in a statement (opens in new tab).In the case of the moon, that happened when asteroid impacts carved out deep depressions in the lunar surface, which redistributed mass and left regions of lower mass. .
The moon reoriented itself, shifting these low-mass "pockets" toward the poles.Researchers had attempted a similar process previously, but by focusing only on the largest lunar craters, those efforts did not consider the net effect of smaller impacts on the moon's poles. .The researchers will continue to simulate the removal of smaller craters from the lunar surface, and they plan to remove features caused by volcanic eruptions in the moon's history.