Measuring Moisture For Chances of Life

The giant balloon hoisted the Johns Hopkins telescope 16 miles high--high enough to get it up above most of the dust and water vapor in the Earth's atmosphere, high enough for a clear look at the dark-blue daytime sky where stars and planets glow with hardly diminished brilliance. Most important of all, it was high enough for the mechanized scope to scan accurately the infra red rays from the sun that were being bounced off Venus.

Laboratory Match. Measured by the 180-million-mile voyage of the space craft Mariner II that took it within a scant 21,000 miles of Venus (TIME, Jan. 4, 1963), the telescope's short as cent seems puny indeed, and it cost the sponsoring Air Force an insignificant $100,000. But the data it collected before it parachuted back to Earth promises to stir up a lively astronomical argument. Mariner confirmed earlier radiotelescope observations and reported that the Venusian surface is far too hot and dry to support any Earth-type life. The flying telescope got a vastly different slant. After careful analysis, says Hopkins Balloon Astron omer John Strong, he is convinced that the clouds hiding the Venusian surface are made of ice particles, just like the Earth's high clouds. And if Venus has that amount of water around, it may also have some sort of life.

By combining 120 separate spectroscopic measurements, Dr. Strong and his assistants got a smooth curve showing how strongly the Venusian clouds reflect different wave lengths of solar infrared. This curve matched almost perfectly the reflection spectrum of an ice-crystal cloud observed in the laboratory. It was wholly different from the curves of dust, liquid carbon dioxide, liquid formaldehyde and the other noxious substances that are generally considered to be the content of Venusian clouds.

Far-Fetched Maneuver. Dr. Strong does not reject Mariner figures, only their interpretation. To take the temperature of a planet's invisible surface by radio is, he thinks, a far-fetched maneuver. All sorts of things besides hot rocks and dust can generate radio waves. They may come, for instance, from storms in the thick Venusian atmosphere, which is churned by twice as much solar energy as hits the Earth. Experts on cloud physics are finding that even gently turbulent clouds give off radio waves.

Dr. Strong also doubts the theory that the carbon dioxide known to be present in the atmosphere of Venus must trap sunlight by a "greenhouse effect" and necessarily make the surface too hot for living organisms. The ice crystals in the clouds, he believes, are so highly reflective that they bounce much of the sun's energy back into space before it gets anywhere near the planet's surface. Thus layers of the Venusian atmosphere may be comparatively cool, perhaps as cool as similar layers on the Earth.

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