A group of astronomers, including Craig Sarazin from U.Va., have made the first high-resolution, high-frequency radio map of the Moon. The image, at a radio frequency of 90 GHz, was made with the MUSTANG2 camera on the Green Bank Telescope, the world’s largest steerable telescope. At this radio frequency, the image shows heat radiation form the lunar surface, and brighter regions are hotter. The image shows many of the same features as seen in more familiar optical images. However, because temperature variations across the lunar surface are smaller than the variations in the amount of reflected sunlight, the image has less contrast than an optical image. Also, the optically dark portion of the Moon in optical light is still visible in the radio, as the surface is still warm.
For more images and information, see the press release by the Green Bank Observatory at https://greenbankobservatory.org/gbt-snaps-hot-photos-of-the-moon/
Below: Radio image of the Moon at 90m GHz made with the MUSTANG2 camera on the Green Bank Telescope. Above: Optical image at the same phase.