The Science & Society Distinguished Public Talks Series presents, "Is the Moon Wet or Dry? Why Do We Care?," with University of New Mexico Regents Professor Zach Sharp on Thursday, Sept. 23 at 5 p.m. in rm. C of the UNM Conference Center located at 1634 University Blvd. N.E. A meet and greet will also be held prior to the talk at 4:30 p.m. The lecture is free and open to the public. Plenty of free parking is available.

Arguably, the most dramatic geochemical distinction between the Earth and Moon has been the virtual lack of water (hydrogen) in the latter. This conclusion was recently challenged on the basis of geochemical data for lunar materials that suggest that the water content of the Moon might be far higher than previously believed.

Sharp and his colleagues have measured the Chlorine isotope composition of Apollo basalts and found that the range of isotopic values are 25 times greater than for Earth. The huge isotopic spread is explained by volatilization of metal halides during basalt eruption, a process that could only occur if the Moon had H concentration'" 1 04 to 105 lower than Earth, implicating that the lunar interior is essentially anhydrous.

Sharp is a Regents Professor in the Department of Earth and Planetary Sciences and the director of the Stable Isotope Laboratory at UNM. His research centers on the use of stable isotope geochemistry in the fields of metamorphic petrology, volcanology, meteoritics, and atmospheric water vapor. His honors include the Minerology Society of America award, and the Society Prize of the European Society for Isotope Research.

The Science & Society Distinguished Public Talks series are co-sponsored by Albuquerque Section of the Institute of Electrical & Electronic Engineers (IEEE), Sigma Xi (the Scientific Research Society), the Department of Physics & Astronomy, College of Arts & Sciences, University Honors Program, and the Division of Continuing Education.

Media contact: Steve Carr (505) 277-1821; e-mail: scarr@unm.edu