NASA’s new Lunar Reconnaissance Orbiter has only been on the job for three months, but even while researchers were calibrating its instruments it was already making new discoveries about our moon. The orbiter swooped down above the moon’s mysterious south pole, and measured temperatures in the permanently shadowed craters that are the lowest ever detected in our solar system. It has also detected traces of hydrogen in various lunar locations, which may indicate buried water ice.
The extent of the deep freeze in the southern lunar craters surprised scientists, says lunar scientist David Paige: “Right here in our own backyard are definitely the coldest things we’ve seen in real measurements.” Temperatures there were measured at 397 degrees below zero. That’s just 62 degrees higher than the lowest temperature possible. Pluto is at least a degree warmer even though it is about 40 times farther away from the sun [AP].
Such temperatures probably allowed for the preservation of ices of water, methane, or ammonia from ancient comet collisions…. Such ices could be valuable resources that human lunar explorers could use. And they would help answer questions about the arrival of such “volatiles” to the Earth-moon system – evidence that Earth’s geological processes have largely erased from its own surface [Christian Science Monitor]. Researchers scheduled the LRO to scrutinize the moon’s south pole in particular because of this combination of potentially useful resources and scientifically interesting sites.
The presence of water ice on the moon has been a point of contention for the past decade. NASA’s 1998 Lunar Prospector detected hydrogen at the poles, but last October a Japanese lunar probe failed to find icy patches in shadowy craters. The latest findings from LRO are intriguing because the orbiter detected hydrogen not just in the dark and icy craters, but also in nearby regions on the sunlit surface.
NASA scientists said Thursday that this could mean water is buried underground. Water could not exist on the surface, where it is exposed to daytime temperatures as high as 220 degrees Fahrenheit…. “We don’t know the abundance or how deeply it is buried” [Los Angeles Times], says project scientist Richard Vondrak.
Researchers won’t have to wait long for more data. In a matter of weeks, a second spacecraft known as the Lunar Crater Observation and Sensing Satellite (LCROSS) will launch a crash-landing probe into the floor of a south-pole crater, Cabeus A. The impact is scheduled for Oct. 9. Scientists will monitor the impact, analyzing the plume of material kicked out of the crater for evidence of water and other ices [Christian Science Monitor].
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