Skylog: The SkyGuide

Moon Rock Tells New Story

Every Rock Tells a Story.  (This rock tells a doozy!)
A new meteorite adds to the already complicated story of volcanism on Earth's Moon.  And, by the way, did you know that the Moon is lopsided?



Perhaps the most difficult part of my job is keeping up.  Science doesn't stand still, allowing me a chance to catch up with astronomical journal articles!  (So many stars, and so little time!)

I just came across something interesting from the good folks at the Planetary Science Research Discoveries (PSRD) website; an article by G. Jeffrey Taylor, of the Hawai‘i Institute of Geophysics and Planetology, on how a little meteorite named NWA 032 is impacting what we thought we knew about the Moon.

This is a science paper, but accessible to a layperson who may have an interest in Luna or in meteorites.  You'll find the paper at:
  http://www.psrd.hawaii.edu/Sept09/NWA032.html

Following is the paper's summary, which grabs what was for me the take-away of the paper:
"...the farside highlands and perhaps the underlying farside mantle are geochemically different from the nearside highlands. The Moon is physically and chemically lopsided."

We have only, literally, just scratched the surface of the Moon!  Let's go!

The detailed research done on NWA 032 and other lunar meteorites highlights the importance of obtaining additional samples of the Moon. Many chemical features of NWA 032 distinguish it from mare basalts collected by the Apollo program and reveal that the lunar interior differs chemically and mineralogically from place to place. Similarly, Randy Korotev (Washington University in St. Louis) has documented that meteorites from the lunar highlands differ significantly from those collected by the Apollo missions, all to the nearside. Although we do not know where a specific meteorite comes from on the Moon, half of them must come from the farside. Thus, Korotev's observations suggest that the farside highlands and perhaps the underlying farside mantle are geochemically different from the nearside highlands. The Moon is physically and chemically lopsided. [emphasis added ~ Michael]

To continue to understand the diversity of the lunar surface and interior, hence to understand its bulk chemical composition and origin, we need more samples. The meteorites will continue to enlighten, but samples from known locations will be particularly valuable because we can put them into the overall geochemical context provided by global remote sensing data. Of course, retrieving samples is complicated, but certainly possible--in the early to mid-1970s, the Soviet Union flew three unpiloted, sample-return missions, Luna 16, 20, and 24. Lunar scientists have identified numerous sites on the Moon where a simple sample-return mission (grab samples, no rover needed) will enhance our knowledge of the Moon and its geological history.

 * Michael Foerster / The SkyGuide