Worlds in Collision
Tim Callahan, religion editor of "Skeptic", presses the case further in claiming that the composition of the atmosphere of Venus is a complete disproof of "Worlds in Collision". "...Velikovsky's hypothesis stands or falls on Venus having a reducing atmosphere made up mainly of hydrocarbons. In fact, the atmosphere of Venus is made up mainly of carbon dioxide—carbon in its "oxidized" form—along with clouds of sulfuric acid. Therefore, it couldn't have carried such an atmosphere with it out of Jupiter and it couldn't be the source of hydrocarbons to react with oxygen in our atmosphere to produce carbohydrates. Velikovsky's hypothesis is falsified by the carbon dioxide atmosphere of Venus."
Transit of Venus
The existence of an atmosphere on Venus was concluded by Mikhail Lomonosov on the basis of his observation of the transit of Venus of 1761 from the Imperial Academy of Sciences of St. Petersburg. He used a two-lens achromat refractor and a weak solar filter (smoked glass) and reported seeing a bump or bulge of light ("Lomonosov's arc") off the solar disc as Venus began to exit the Sun. Lomonosov attributed that effect to refraction of solar rays through an atmosphere; he also reported the appearance of a sliver around the part of Venus that had just entered the Sun's disk during the initial phase of transit. In 2012, Pasachoff and Sheehan reported, based on knowing what Venus's atmosphere would look like because of Pasachoff and Schneider's observations of the 2004 transit of Venus, that what Lomonosov reported was not Venus's atmosphere. To make a decisive test, a group of researchers carried out experimental reconstruction of Lomonosov's discovery of Venusian atmosphere with antique refractors during the transit of Venus on 5–6 June 2012. They observed the "Lomonosov's arc" and other aureole effects due to Venus's atmosphere and concluded that Lomonosov's telescope was fully adequate to the task of detecting the arc of light around Venus off the Sun's disc during ingress or egress if proper experimental techniques as described by Lomonosov in his 1761 paper are employed.