Excerpt from smnweekly.com
By David M. DeMar
New radio telescope data from the National Radio Astronomy Observatory has revealed for the first time ever just what Venus has under its thick veil of clouds that otherwise occlude its surface from view.
25 million miles distant from us, Venus looks to the naked eye – or through a light telescope – much like a cloudy marble, thanks to the thick cloudbanks of carbon dioxide ringing the planet. However, the surface underneath, long a mystery to planetary scientists, has been laid bare thanks to the work of Puerto Rico’s Arecibo Observatory radio transmitter and the Green Bank Telescope, a radio telescope located in West Virginia and operated by the National Science Foundation.
The two facilities worked together with the NRAO in order to uncover the hidden surface of Mars. Arecibo sent radar signals to Venus, where they penetrated the thick atmosphere and bounced off the ground. The returning radio signals were picked up by the GBT in West Virginia in a process known as bistatic radar; the result is a radar image that shows craters and mountains strewn across the surface of Venus at a surprisingly high resolution.
The image is bisected by a dark line, representing areas where it’s particularly difficult to receive useful image data through the use of bistatic radar. However, scientists are intending to compare multiple images as time goes by in order to identify any active geologic processes on the surface of Venus such as volcanic activity.
It’s no particularly easy task to compare radar images in search of evidence of any change in this manner says Smithsonian senior scientist Bruce Campbell, but the work will continue. Campbell, who works at the National Air and Space Museum in the nation’s capital and is associated with the center for Earth and Planetary Studies, added that combining images from the latest NRAO endeavor and others will yield large amounts of data on how the surface of Venus might be altered by other processes.
The radar data, and a scientific paper based on it, will be published in April in Icarus, the scientific journal dedicated to studies of the solar system.