Broca's Brain - Carl Sagan [64]
With such organic clouds now so thoroughly discredited, why do we hear about space-vehicle research having corroborated Velikovsky’s thesis? This also requires a story. On December 14, 1962, the first successful American interplanetary spacecraft, Mariner 2, flew by Venus. Built by the Jet Propulsion Laboratory, it carried, among other more important instruments, an infrared radiometer for which I happened to be one of four experimenters. This was at a time before even the first successful lunar Ranger spacecraft, and NASA was comparatively inexperienced in releasing the scientific findings. A press conference was held in Washington to announce the results, and Dr. L. D. Kaplan, one of the experimenters on our team, was delegated to describe the results to the assembled reporters. It is clear that when his time came, he described the results with somewhat the following flavor (these are not his exact words): “Our experiment was a two-channel infrared radiometer, one channel centered in the 10.4 micron CO2 hot band, the other in an 8.4 micron clear window in the gas phase of the Venus atmosphere. The objective was to measure absolute brightness temperatures and differential transmission between the two channels. A limb-darkening law was found in which the normalized intensity varied as mu to the power alpha, where mu is the arccosine of the angle between the local planetary normal and the line of sight, and—”
At some such point he was interrupted by impatient reporters, unused to the intricacies of science, who said something like “Don’t tell us the dull stuff; give us the real poop! How thick are the clouds, how high are they, and what are they made of?” Kaplan replied, quite properly, that the infrared radiometer experiment was not designed to test such questions, nor did it. But then he said something like “I’ll tell you what I think.” He went on to describe his view that the greenhouse effect, in which an atmosphere is transparent to visible sunlight but opaque to infrared emission from the surface, needed to keep the surface of Venus hot, might not work on Venus because the atmospheric constituents seemed to be transparent at a wavelength in the vicinity of 3.5 microns. If some absorber at this wavelength existed in the Venus atmosphere, the window could be plugged, the greenhouse effect retained, and the high surface temperature accounted for. He proposed that hydrocarbons would be splendid greenhouse molecules.
Kaplan’s cautions were not noted by the press, and the next day headlines could be found in many American newspapers saying: “Hydrocarbon Clouds Found on Venus by Mariner 2.” Meanwhile, back at the Jet Propulsion Laboratory, several Laboratory publicists were in the process of writing a popular report on the mission, since called “Mariner: Mission to Venus.” One imagines them in the midst of writing, picking up the morning newspaper and saying, “Hey! I didn’t know we found hydrocarbon clouds on Venus.” And, indeed, that publication lists hydrocarbon clouds as one of the principal discoveries of Mariner 2: “At their base, the clouds are about 200 degrees F and probably are comprised of condensed hydrocarbons held in oily suspension.” (The report also opts for greenhouse heating of the Venus surface, but Velikovsky has chosen to believe only a part of what was printed.)
One now imagines the Administrator of NASA passing on the good tidings to the President in the annual report of the Space Administration; the President handing it on yet another step in his annual report to Congress; and the writers of elementary astronomy texts, always anxious to include the very latest results, enshrining this “finding” in their pages. With so many apparently reliable, high-level and mutually consistent reports that Mariner 2 found hydrocarbon clouds on Venus, it is