The National Radio Astronomy Observatorys Green Bank Telescope in Pocahontas County and the Arecibo Observatorys huge radiotelescope in Puerto Rico teamed up earlier this month to generate images of subterranean rock clusters and changes in the composition of dust up to 50 feet below the surface of the moon.

To produce the images, radar signals beamed from the Arecibo telescopes powerful transmitter penetrated 33 to 50 feet through the lunar surface and rebounded back to Earth, where they were detected by the sensitive receivers on the Green Bank Telescope. One image was taken of a portion of the moons Sea of Serenity, not far from Apollo 17s landing site in 1972. Changes in the composition of lunar dust and differences in the abundance of sub-surface rocks could be seen in the radar observations.

A second image was made of a 34-mile wide, 2-mile deep impact crater known as Aristillus, where a dark, halo-like feature surrounding the crater was determined to have been caused by pulverized debris flying out of the crater. The image also shows traces of lava-like features produced when lunar rock heated during impact flew beyond the perimeter of the crater.

According to a release from the National Radio Astronomy Observatorys headquarters in Charlottesville, Va., the subterranean lunar images will help scientists interpret the history of the moon, which is often obscured by billions of years of dust accumulations. They will also help space program researchers better understand the geology of previous lunar landing sites and plan for future landings on the moon.

In late April, the Green Bank Telescope teamed up with the Arecibo scope to observe a passing asteroid known as 2006 SX 217. Once again, radar pulses from Arecibo were bounced off the asteroid as it passed about 3 million miles from Earth, and then received and decoded by the West Virginia observatory. Since the asteroid was heading away from Earth and into the glare of the sun, optical telescopes were unable to observe its passing.

Because the asteroid is spinning, astronomers will be able to analyze how the returning radar signals are spread out, and after careful analysis, be able to construct a 3-D model of it. Preliminary observations indicated that the asteroid is about 4,000 feet in diameter larger than previously thought and unusually dark. An astronomer at the Arecibo observatory described the asteroids color as being about as black as toner in a copier.

The asteroid will not pass close enough to Earth for similar observations until 2066.

The 305-meter Arecibo radiotelescope, perched atop a limestone sinkhole and the 100-meter, fully steerable Green Bank Telescope have cooperated on a number of similar observations over the years, using a technique known as bi-static radar. In 2001, the West Virginia telescopes first scientific observations of the cloud-shrouded surface of Venus and of a smaller asteroid were made in conjunction with the Puerto Rico telescope, using the bi-static technique.

Both observatories are funded through the National Science Foundation. In 2012, an NSF review committee recommended that the Green Bank Telescope be divested from the portfolio of observatories the NSF funds by 2017, while keeping the older Arecibo scope, completed in 1963.

Reach Rick Steelhammer at 304-348-5169 or rsteelhammer@wvgazette.com.

Original post:

Green Bank Telescope helps chart underground features on Moon, provide 3-D image of asteroid