New Moon Map Shows Uranium in Short Supply
A map of uranium levels on the lunar surface, as measured by the Kaguya mission. The highest levels are at 2.1 parts per million (ppm) at Copernicus crater (C). E and W stand for the east and west highlands on the far side of the moon; A, the Apennine Bench; I, Mare Imbrium; J, Montes Jura; S, South Pole — Aitken Terrane; and T, Mare Tranquillitatis. Full Story.
Credit: N. Yamashita et al., Geophysical Research Letters

A new map of uranium on the moon has revealed the lunar surface to be a poor source of the radioactive stuff, but it could help solve mysteries as to how the moon formed.

This new moon uranium map dampens hopes of a nuclear power industry on the lunar surface, researchers said.

Proponents of lunar bases and future lunar colonies have long pointed to many of the moons minerals, along with water, as being useful to support such efforts.

"Forget things like uranium mines or nuclear reactors," said cosmochemist Robert Reedy, a member of the Kaguya science team and a senior scientist at the Tucson-based Planetary Science Institute. "The concentrations are very far from being of commercial levels."

Uranium on the moon

The new map was created using data from Japan's Kaguya spacecraft, which launched in 2007. The spacecraft found uranium on the moon, along with other radioactive elements, with its advanced gamma-ray spectrometer.

Kaguya crashed into the moon's surface at the end of its mission last year.

The new moon uranium map clearly shows the element is not abundant on the moon. In moon rock, it appears in quantities less than in many Earth granites.

Moon's early history

Still, by analyzing the ratio between the naturally radioactive elements uranium and thorium scientists may yield new insights into the formation and evolution of the moon's surface. In the new map, significant variations in the ratio between uranium and thorium were revealed.

For instance, average uranium abundances could differ by some 60 percent between the east and west highlands on the far side of the moon, while thorium abundances between those areas varied only 10 percent.

These new findings suggest the formation of the lunar crust might not be as uniform as had long been thought.

"The Kaguya gamma-ray spectrometer team wants to finish getting maps for as many elements as possible before drawing detailed conclusions on the Moon's history," Reedy said.

The scientists detailed their findings online May 20 in the journal Geophysical Research Letters.