9781916296459_

A concise history of Venus from the earliest pre-telescopic observations, to the often fraught efforts of 18th century astronomers to observe transits, to the robotic probes of the Space Age. This 12,000 word eBook Short Read describes how our views of Venus have changed over the last two centuries - from a tropical or possibly ocean world to a hellish place with surface temperatures high enough to melt lead. Despite these hostile conditions, the possibility of life cannot be ruled out.

Did you know?

*The minimum Earth-Venus distance of 40 million km (25 million miles), rather less than that of Mars, which is never closer than 56 million km (35 million miles).

*Venus is the only planet in the solar system with a rotation period longer than its orbital period. It rotates on its axis once every 243.025 days, but the orbital period is only 224.701 days; in other words, a Venusian 'day' is longer than a Venusian 'year'. Along with that of Uranus, the rotation of Venus is retrograde (i.e., clockwise as viewed from above the Sun's north pole). The rotation of most other large Solar System bodies is prograde (i.e., in an anticlockwise direction as viewed from above the Sun's north pole).

*The obliquity or axial tilt of Venus is 177°21' in relation to the plane of its orbit, but that is based on the convention that planetary rotation is always direct. If the rotation of Venus is taken to be retrograde, then the obliquity is just 3°39', which is lower than any other planet except Mercury.

*There are several historical accounts of daytime sightings of Venus. Danish astronomer Tycho Brahe (1546-1601) reported daylight sightings in both the morning and the evening in February 1587. Napoleon Bonaparte is reputed to have seen it at noon while attending a public event in Luxembourg after noticing that the assembled crowd were staring up at the sky rather than listening to him. Napoleon's followers subsequently referred to Venus as being 'the star of the Conqueror of Italy'. Venus was also seen in daylight during the inauguration of Abraham Lincoln for his second term as President on 4 March 1865, and it again caused a considerable commotion among those attending.

*Venus is bright enough to cast shadows at night, a phenomenon that was first recorded by the Roman author Pliny the Elder (AD 23-79). Unlike the diffuse-edged shadows cast by the Sun or the Moon, shadows cast by Venus are sharp-edged. This is because the Sun and the Moon are extended objects, whereas Venus is effectively a point source.

*The US Mariner 2 became the first crewless space probe to reach another planet, when it made a fly-by of Venus on 14 December 1962, passing to within 34,773 km (21,607 miles) of the planet. The probe was based on the Ranger lunar impactor but enjoyed rather better fortune. At the time of the Venus flyby, Rangers 1 to 5 had all failed, and the Ranger program did not chalk up its first success until Ranger 7 in July 1964.

*A total of six probes have used Venus for a gravity assist while en route to other parts of the Solar System. This is more than for any other planet. Jupiter has featured in three gravity assists and Mars in two. Three other probes made gravity assist flybys of Venus but also returned important data from the planet. The US Mariner 10 probe returned the first pictures of Venus while on its way to Mercury and the Soviet probes Vega 1 and Vega 2 released landers and atmosphere probes while en route to Halley's Comet.

Venus: Queen of Heaven or Hell Planet?

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