Wednesday, April 30, 2008

Dr. Rebecca Ghent of the "LRO 24" presents "a Striking History"

On March 11, Dr. Rebbecca Ghent of the University of Toronto was chosen by NASA as one of the "LRO 24," a group picked by NASA to help decide how best the Lunar Reconnaissance Orbiter will collect science on its mission later this year. The LRO-LCROSS mission is nearly assembled and was reportedly scheduled for vacuum chamber stress testing under supervision by the Goddard Spaceflight Center.

Among the stated goals of LRO are testing new technologies, identifying potential landing sites, sampling the back-scatter from Cosmic Rays and solar particles from the lunar surface and the moon's "striking" geological history, which is believed to be a literal recording of the same history of the Solar System since the Moon formed 4.725 billion years ago.

Overnight Chuck Wood of the Lunar Photograph of the Day (LPOD) wiki has opened a discussion of an "important article" in the May issue of Geology showing an incredible mosaic of lunar radar data.

The image put together by Dr. Ghent and colleagues has resulted in an wrap-around image of lunar morphology adding to debate over the long-theorized relationship between the Mare Orientale impact basin, the "eastern sea" marking the eastern limb of near side with it's familiar bull's eye, and lava-filled floors of older impact craters in the southern highlands and as far away as Shackleton nestled adjacent to the lunar south pole and within the ancient Aiken Basin, eighty percent of which is on the far side and invisible to Earth-bound observations.

Aside from helping establish the relationship between older craters and the freshness of their basalt-filled apparently newer floors, Ghent and her colleague's work will greatly serve the LRO's mission of discovering in situ resources.

Like all but a few of the large basalt-filled lunar "seas" of Earth's moon, which make up such a predominant feature characterizing the familiar near side, tidally locked into ever facing Earth, Mare Orientale is a "mascon," a localized concentration of mass perturbing the orbits of satellites in both equatorial and polar low lunar orbit and demonstrating the still mysterious anisotropy of the moon itself. The center of the large prominent basin is lower, dipping down below the mean levels of the surrounding surface. Two concentric rings encircling the inner basin are also basalt-filled, dipping lower than the mean surface's distance from the unresolved lunar "center."

As with all other mascons, gravity increases in effect on the space surrounding them in inverse proportion to their seeming size. Gravimetric maps of the lunar "seas" show what appears to be a mountainous mass peaked at Mare Orientale's basin with surrounding ridges rather than the circular valleys mapped by radar and Kaguya's laser altimeter.

Now among the "LRO 24," Dr. Ghent teaches geology at the University of Toronto.

She earned a bachelor’s degree in Physics in 1993 from Randolph-Macon Woman’s College. She earned her masters degree a year later at Georgia Tech and taught Physics at Georgia's Gordon College before returning to graduate school to study geology. In 2002, Ghent earned a Ph.D. in geology from Southern Methodist University and held a postdoctoral fellowship at the Smithsonian Institution in DC in 2006, before becoming part of the faculty at Toronto.

No comments: