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KRONOS Vol IV, No. 4
A NOTE ON THE TEMPERATURE OF VENUS
C. J. RANSOM
The special issue of KRONOS - Velikovsky and Establishment Science - cites (p. 132) a calculation of mine relating to the temperature of Venus. This calculation should be put in context with the temperature debate, so that its result is neither misconstrued nor used as a real value.
Astronomer W. C. Straka wrote in 1972 that if Venus were incandescent (say, 2000°K) only 3500 years ago, then it would now be much hotter than the measured temperature. Later, Sagan wrote that, if Venus were 6000°K about 3500 years ago, its temperature today would be lower than the freezing point on Earth. Obviously, both honorable astronomers cannot be correct.
Indeed, Sagan's suggestion is so illogical as to cause wonder about his motive for making it. Surely he, of all people, would not insist that Venus had a temperature even greater than 6000°K only 3500 years ago, yet this would have to be the case for his argument to hold true and be consistent with the temperature Venus now has. He implicitly assumes that no radiation from the Sun has impinged on Venus for the last 3500 years. Yet, elsewhere, and repeatedly, Sagan has claimed that a greenhouse effect keeps Venus hotter than anyone except Velikovsky ever expected. For consistency, should not the Venus greenhouse also be asked to function without energy from the Sun? Similar assumptions should be applied to both models - no solar input, if Sagan thinks that was the appropriate condition .
Straka's postulation was considerably more reasonable than Sagan's; however, Straka offered no support for his conclusion. It is permissible to speculate without quantitative analysis, but such a speculation cannot be advanced as "proof" that another is incorrect. This, however, was the apparent intent of Straka's statement. Nevertheless, his argument was reasonable enough to investigate further, so I made a rough calculation. My purpose was to determine whether Straka was uncontestably correct or the question required more detailed study to be resolved.
My calculation assumed a simple, exponential, decay rate. Observational data possibly indicating a cooling trend for Venus were included. A regression analysis was performed to see whether an exponential curve could be fit to the last few points yet lead back to a temperature of more than 1000°K 3500 years ago. A reasonable curve was found for T = 1184°K 3500 years ago. (The curve is steep for times around 3500 years ago, so that values considerably higher or slightly lower than 1184°K would be compatible with my assumption.)
This of course does not demonstrate that the temperature of Venus was actually 1184°K 3500 years ago. It reveals only that a rough calculation admits the possibility that the temperature of Venus was then of that order and that Straka's argument was either purely speculative or based on a more complex model. If the latter were the case, he should have included his calculations with his comment.
An accurate thermal model of Venus would be extremely difficult to develop. If one were attempted, however, it would more than likely be based on modern ideas about convection in planetary interiors, enabling them to lose heat much faster than by conduction alone. At first glance, one would question whether such ideas might exclude the possibility that Venus has had a thermal history consistent with Velikovsky's suggestions.
[*!* Image: INSERT KIV2_27.JPG] A 3500 Year Temperature History of Venus, Using Dr. Ransom's Initial Temperature of 1184 Kelvin.
Dr. C. J. Ransom, by an independent algorithm, had computed an 1184 Kelvin temperature for the Venus of 3500 years ago, by "back calculation" from an assumed 700 Kelvin today.
Dr. Talbott's program, beginning with an 1184 Kelvin temperature 3500 years ago, deduces a 715 Kelvin temperature today. This reasonably close correlation lends significant additional evidence for Dr. Velikovsky's principal thesis.