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Science Frontiers ONLINE No. 101: Sep-Oct 1995 |
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The metal-frosted mountains of venus!
Venus is a very hot planet with a mean surface temperature of 740°K. It is so hot there that some metal compounds of chlorine, fluorine, and sulfur are vaporized in some locales. Such metallic "mists" could well coat out as "frost" on the cooler, higher elevations. Actually, two outstanding Venusian anomalies can be explained by such metallic "frosts."
- Radar signals from earth are strongly reflected from the planet's mountains and high plateaus. These regions may owe their unusually high reflectance to metallic "frosts" consisting of such radarbright minerals as pyrite, which is probably present in vapor form at lower, hotter elevations.
- During the 1978 Pioneer Venus mission, four instrumented probes plunged into the Venusian atmosphere. All instruments with external sensors on all four probes failed mysteriously 12.5 kilometers above the planet's surface. Thinking is that the probes pierced a cloud deck of metallic vapor that condensed on the cold sensor surfaces. (Anonymous; "Metal 'Frost' on Venus?" Sky and Telescope, 90:13, August 1995.)