The uncertainty of science: According to a paper published at the end of October, scientists have used data from the LADEE lunar orbiter (that circled the Moon in 2013-2014) and found that the surface of the Moon is extremely arid, and if there is any ice trapped in the permanently shadowed craters at the poles it did not come from meteorite impacts elsewhere on the Moon. From the abstract:

The upper bound for exospheric water derived here from data collected in 2013–2014 by the neutral mass spectrometer on the Lunar Atmosphere and Dust Environment Explorer spacecraft [LADEE], about three molecules/cc, pales in comparison to the concentration of ∼15,000 molecules/cc needed to sequester the meteoritic water influx. The only pragmatic conclusion is that the hypothesis for water ice accumulation at the poles due to exospheric transport is false.

The theory had been that any water from these meteorites could have been transported by various processes to the polar cold traps. This data says that did not happen, and if there is water ice in the polar cold traps, its origin remains unknown, though comet impacts at the poles might have been a source.

This result also appears to contradict other orbital data that has suggested there is some water in the lunar regolith at mid and low latitudes.