Mercury Radar Imaging: Evidence for Polar Ice
Abstract
The first unambiguous full-disk radar mapping of Mercury at 3.5-centimeter wavelength, with the Goldstone 70-meter antenna transmitting and 26 antennas of the Very Large Array receiving, has provided evidence for the presence of polar ice. The radar experiments, conducted on 8 and 23 August 1991, were designed to image the half of Mercury not photographed by Mariner 10. The orbital geometry allowed viewing beyond the north pole of Mercury; a highly reflective region was clearly visible on the north pole during both experiments. This polar region has areas in which the circular polarization ratio (μ_c) was 1.0 to 1.4; values <~0.1 are typical for terrestrial planets. Such high values of μ_c have hitherto been observed in radar observations only from icy regions of Mars and icy outer planet satellites.
- Publication:
-
Science
- Pub Date:
- October 1992
- DOI:
- 10.1126/science.258.5082.635
- Bibcode:
- 1992Sci...258..635S
- Keywords:
-
- Ice Mapping;
- Mercury Surface;
- Polar Regions;
- Radar Imagery;
- Nasa Space Programs;
- Radio Astronomy;
- Very Large Array (Vla);
- Lunar and Planetary Exploration