The new ngRADAR at the Green Bank Telescope offers unprecedented Earth-based views of the solar system
When a baseball pitcher throws a fastball, the speed pops up on the jumbotron thanks to radar. The technology is also useful for air traffic control, highway speed traps and weather forecasting—and it’s not reserved for Earth. Astronomers have used radar to probe the planets and asteroids around us, measuring their speed as they whiz around the sun and imaging the details of their surface.
A new tool promises to ramp up this brand of science by offering more detailed astronomical radar capabilities than ever before. The team behind a pioneering radar system at the Green Bank Telescope in West Virginia released their first results last month at the 241st meeting of the American Astronomical Society, revealing unprecedented detail on the moon and detecting a near-Earth asteroid. The telescope’s novel radar system, called Next Generation Radar (ngRADAR), “produced results that were beyond expectations,” says Flora Paganelli, a project scientist at the National Radio Astronomy Observatory’s (NRAO’s) radar division.
The ngRADAR system uses the Green Bank Telescope as a huge transmitting antenna, and it uses the Very Long Baseline Array of radio telescopes spread across the U.S., Hawaii and the Virgin Islands as a miles-wide receiver. Green Bank has a 100-meter-diameter dish—a radio telescope’s equivalent of a mirror—making it the largest steerable antenna on Earth, uniquely suited to this job.
To test the new system, the ngRADAR team turned toward the moon to image an Apollo landing site and the prominent Tycho Crater. These are the “highest-resolution images ever taken of the moon from a ground-based system,” Paganelli says. They reveal meter-sized features and are likely to be of great interest to lunar scientists.
“Being able to see distinct surface geology on the floor of Tycho Crater from the ground has been quite breathtaking,” says Patrick Taylor, radar division head at NRAO and Green Bank Observatory. “It will be interesting to see how planetary geologists can make use of this information.”