19-05-2007 Venus (Article 86)

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Simon Kenny
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Location: Shannon, Co. Clare, Ireland

19-05-2007 Venus (Article 86)

Post by Simon Kenny » Wed Feb 04, 2009 10:58 am

Venus (Article 86)

A casual observer might not know what it is, but if the Western horizon is clear about a half hour after sunset any evening between January and June 2007, it is unmissable. That intense bright spark is not a plane, a satellite, or a UFO — it is our nearest planetary neighbour that can come within ten million miles of Earth.

Venus features in the folklore of many cultures: the Aztecs of ancient Central America saw Venus as the fearsome god who ruled the midday sky, who could only be placated by human sacrifice. The Mayan culture saw the morning appearance of Venus as an omen of war. Mayans so feared Venus that they covered their chimneys, doors and windows to prevent its light from entering their houses and bringing bad luck. Ancient Indo — European cultures also associated Venus with natural and man-made disasters. We derive our Venusan myths and the name from the Romans, who were so impressed by its sparkle in the sky, that they called it after their goddess of love. Looking up at its intensely bright glint shining through the sun’s glow, it is easy to see why the Romans were charmed.

Venus was long regarded as our twin in the Solar System. Not only does it come closer to us than other planets, it is about the same size, only a little smaller. As details of the surface were hidden by dense cloud, people could only speculate on what, or who existed on its surface. Until the 1950s serious astronomers speculated that Venus had a climate range rather like Earth’s. The climate was expected to be warmer due to its greater proximity to the Sun and those clouds were thought to ensure planet-wide rainfall. However, the fate of the Russian Venera space probes, hinted at a very different reality: two of them were crushed by the enormous atmospheric pressure on the surface, which was measured at ninety times that on the Earth’s surface. The surface temperatures were much higher than expected: 500°C, enough to melt lead, hotter even than Mercury’s surface, which is closer to the Sun. Even the clouds, so bright from Earth, consist of sulphuric acid, or battery acid! The intense heat and pressure is explained by the atmosphere, which is about 97% carbon dioxide, which is heavier than air and traps the Sun’s heat, causing a runaway greenhouse effect, a cautionary tale for planet Earth.

NASA’s 1990 — 1994 Magellan mission to Venus has given us views of its surface in unprecedented detail. Using radar to image the surface through its dense clouds, it uncovered a surface that is waterless, dotted with volcanic features, probably still active and huge mountain and upland areas. The Magellan images of Venus are well worth seeing and can be viewed on: http://www2.jpl.nasa.gov/magellan/images.html
Yes, Venus could be considered a bright planet but with dark secrets — like a neighbour from hell! Clear skies!

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