Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site utastro.UUCP Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!mhuxn!ihnp4!qantel!dual!mordor!ut-sally!utastro!bill From: bill@utastro.UUCP (William H. Jefferys) Newsgroups: net.origins Subject: Re: Venus and Velikovsky Message-ID: <705@utastro.UUCP> Date: Thu, 12-Sep-85 18:07:25 EDT Article-I.D.: utastro.705 Posted: Thu Sep 12 18:07:25 1985 Date-Received: Sun, 15-Sep-85 10:02:22 EDT Distribution: net Organization: U. Texas, Astronomy, Austin, TX Lines: 197 I submitted this over a week ago, but it apparently didn't make it out of our site. ------ [Ted Holden writes, in response to my article] > Wildt had proposed a reasonable greenhouse theory calling > for surface temperatures around 275 F, based on these same > hypotheses regarding the age of the solar system and carbon > dioxide in Venus' atmosphere. A Cray I wouldn't have helped him > any more than his calculator; his hypotheses were wrong. Absolutely untrue. Not only do the computer calculations of the Greenhouse Effect accurately predict the 730 K temperature at the surface of Venus, but they accurately reproduce the temperature profile in the atmosphere as observed by spacecraft landing on Venus [1]. The major problems with Wildt's hypotheses were that he didn't know how truly massive Venus' atmosphere was, and he didn't know that there was water vapor on Venus in sufficient amounts to plug the 3.5 micrometer gap. > The runaway-greenhouse theory was concocted by Sagan and > others to deal with this wild departure from what their major > theories regarding our solar system would have called for. It > can be shown to be rubbish by any of several lines of argument > which are well documented. We shall soon see what's rubbish. > Consider that Venus rotates very slowly, about once in 58 > earth days or so. If Venus' sole source of heat was the sun, as > called for by the runaway-greenhouse theory, we would expect it > to be a LOT hotter on the sunlit side of Venus than on the dark > side. Indeed, it would be perfectly logical to expect much > larger temperature differentials between day and night on Venus > than on the earth. Radio emmision analyses have never shown this > to be the case, however. Writing in PHYSICS TODAY, in 1961, > Frank Drake of the National Radio Astronomy Observatory wrote > that "there is little surface temperature difference between the > illuminated and dark hemispheres of Venus". Further exhaustive > radio spectrum analyses which Sagan and David Morrison have > conducted have failed to turn up a shred of evidence which they > could use in their anti-Velikovsky crusading. Morrison claimed > to have discovered "no phase effect after 100 hours of > observations". Ted probably got this argument from the introduction to *Velikovsky Reconsidered* [2]. It's true, the phase effect on Venus is very small. David Morrison (who is Professor of Astronomy at the University of Hawaii, and past Charman of the Division of Planetary Sciences of the American Astronomical Society) says of this idea [3]: "It will be remembered that it was the nonvariation of cloud-top temperatures that apparently led Velikovsky first to hypothesize an internal heat source on Venus. He neglected the alternative possibility that the constancy of temperature could be due to the massive heat capacity of a thick atmosphere. His was perhaps an understandable omission, since the atmosphere of Venus was thought twenty-five years ago to be Earth-like. But no such excuse exists for his supporters today, who are well aware of the 100-atmosphere surface pressure on the planet. "The chain of logic on the question of surface temperature variations is virtually the opposite of that published in defense of Velikovsky. *A large greenhouse effect can only be maintained by a massive atmosphere, and a massive atmosphere must damp out surface temperature variations.* Therefore the absence of such variations is *expected* where a large greenhouse effect exists. The reason the radio observers (and I was one of them) expressed some surprise at the lack of variation seen in their data was that there were previous suggestions that this "microwave phase effect" had been detected, *not because their results contradicted some preconception based on a greenhouse model*. The radio data provide a very weak rod indeed with which to beat greenhouse explanations of the temperature of Venus." [Emphasis added]. > The British astronomer Firsoff simply states: > > "Increasing the mass of the atmosphere may intensify the > greenhouse effect, but it must also reduce the proportion of > solar energy reaching the surface, while the total of the > available energy must be distributed over a larger mass and > volumn. Indeed, if the atmosphere of Venus amounts to 75 > air masses... the amount of solar energy per unit mass of > this atmosphere will be about .01 of that available on the > earth. Such an atmosphere would be strictly comparable to > our seas and remain stone-cold, unless the internal heat of > Venus were able to keep it at temperatures corresponding to > the brightness temperatures derived from the microwave > emission." > > That is, unless Velikovsky is right. This argument can also be found in *Velikovsky Reconsidered* [2]. Firsoff is demonstrably wrong. Firsoff's assertions (which can be found in [4]) are contradicted by both observations and calculations [1]. Indeed, Firsoff was trying to argue that the surface of Venus was *cold*, despite the clear evidence to the contrary which even Velikovskyites accept. To me it seems disingenuous for Velikovsky's supporters to point to Firsoff to bolster their position that Venus is young and hot. If Firsoff was so wrong about the temperature of Venus what gives them confidence that he was right about the Greenhouse Effect? The contemporaneous direct measurements of the light available at the surface of Venus made by the Venus lander Venera 8 show that about 1% of the solar flux actually reaches the surface of Venus. According to Morrison, this is quite adequate to maintain the observed temperature via the Greenhouse Effect [5]. Though questioned by Velikovsky's supporters [6], these measurements have been confirmed by subsequent Venus landers. The most recent of the Venera series used the available light to take pictures of the surface of Venus which were transmitted' to Earth [7]. > Of course, Jupiter, Saturn, AND Venus radiate more energy > than they absorb; no greenhouse theory of any kind could account > for that. And even a pathalogical liar like Sagan would be > loathe to make the statement that Venus retains heat from it's > formation after 4.6 billion years. Wrong again. Venus does *NOT* radiate more energy than it absorbs. Direct measurement by orbiting spacecraft shows that the total energy radiated by Venus is precisely what one would expect from an otherwise cold body at that distance from the Sun. Morrison writes [8] "That Venus has a "hot" surface and a large internal heat source is perhaps the most widely quoted prediction made by Velikovsky. Repeated measurements of the cloud-top temperatures at a variety of infrared wavelengths, including those from the recent Mariner 10 flyby, however, verify that the total energy radiated from Venus is equivalent to that from a black body of about 230 K, or *just what one would expect in the absence of any internal energy source. Thus there is no evidence that Venus radiates more energy than it receives from the Sun.*" [Emphasis added]. These facts have not changed since Morrison wrote his article (Taylor *et. al.* [9]). In the same article, Morrison demonstrates convincingly that *even if we were to accept Velikovsky's hypothesis* that Venus was heated to approximately the melting point of rock ~3000 years ago, it would have cooled so rapidly that the present-day contribution of this heat would produce no more than about a 10 K elevation of the surface temperature of Venus, too small to measure. Velikovsky did not realize that a hot body cools off *much* more rapidly than a cool one, believing erroneously that the drop in temperature from the melting point of rock to 750 K would be linear in time. In fact, the decline from 2250 K to 750 K would have taken place in at most a few hundred years [10]. > > HOLDEN'S PRAYER > > "Thank you Lord for not making me a dingo dog, a citizen of > any communist nation, or a member of any profession which > is obligated to defend major theories which amount to > flagrant bullshit before an incredulous world, and then > cry and attempt to act outraged when the world reacts by > seeking legal limits to the extent to which that profession > may determine the manner in which it's children are being > educated with it's money." Grow up, Ted. This makes you sound very childish. REFERENCES [1] Donahue, T. M. and Pollack, J. B. (1983), in *Venus*, D. M. Hunten. *et. al.*, Editors. University of Arizona Press. p. 1028. [2] The Editors of Pensee (1976), *Velikovsky Reconsidered*, Doubleday. p. xxv. [3] Morrison, D. (1977), in "Scientists Confront Velikovsky*, D. Goldsmith, Editor. Cornell University Press. pp. 164-165. [4] Firsoff, V. A. (1973), *Astronomy and Space Science* *2*, No. 3. [5] Morrison, D. (1977), in "Scientists Confront Velikovsky*, D. Goldsmith, Editor. Cornell University Press. p. 159. [6] The Editors of Pensee (1976), *Velikovsky Reconsidered*, Doubleday. p. xxiv. [7] Florenskiy, K. P., *et. al.* (1983), in *Venus*, D. M. Hunten. *et. al.*, Editors. University of Arizona Press. pp. 137-153. [8] Morrison, D. (1977), in "Scientists Confront Velikovsky*, D. Goldsmith, Editor. Cornell University Press. p. 159. [9] Taylor, F. W., *et. al.* (1983), in *Venus*, D. M. Hunten. *et. al.*, Editors. University of Arizona Press. p. 671. [10] Morrison, D. (1977), in "Scientists Confront Velikovsky*, D. Goldsmith, Editor. Cornell University Press. pp. 161-162. -- Glend. I can call spirits from the vasty deep. Hot. Why, so can I, or so can any man; But will they come when you do call for them? -- Henry IV Pt. I, III, i, 53 Bill Jefferys 8-% Astronomy Dept, University of Texas, Austin TX 78712 (USnail) {allegra,ihnp4}!{ut-sally,noao}!utastro!bill (UUCP) bill@astro.UTEXAS.EDU. (Internet) Brought to you by Super Global Mega Corp .com