Phosphine gas detected in the clouds of Venus could be a sign of life or some strange unknown chemistry, Lisa Grossman reported in “Possible sign of life is found on Venus” (SN: 10/10/20 & 10/24/20, p. 6).
The story brought back memories for reader Bruce Hapke, a professor of planetary science at the University of Pittsburgh.
“In 1975, my colleague Robert M. Nelson and I published the first high-quality, broadband spectrum of the clouds of Venus … which we obtained using the 106-inch telescope at McDonald Observatory in Texas,” Hapke wrote. “This spectrum turned out to be identical to that of a form of elemental sulfur, and we suggested that tiny particles of sulfur in the clouds are responsible for their yellowish color. The sulfur comes from volcanic eruptions.”
By then, “Russia had launched several unmanned spacecraft that had successfully landed on the surface of