Readers ask about life on Venus and high-energy cosmic rays

Venusian recollection

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 Venus. In the paper, we pointed out that these spacecraft had not been sterilized and probably were badly contaminated with microscopic, single-cell forms of life, which the landers would then shed as they parachuted down through the clouds,” Hapke wrote. “We also pointed out that many types of microbes are extremely hardy and can readily survive the vacuum of space by going dormant until they are in a hospitable environment. Many can live in sulfuric acid. On Earth they are found in acid drainage from coal mines. Many are anaerobic and do not require oxygen. Instead they generate energy for their metabolism by chemically changing … sulfur that they ingest. E­ssentially, they survive by eating sulfur,” he wrote. “If life does exist in the Venus clouds, it is highly likely to consist of immigrants from Earth.”

Other research groups have been questioning the phosphine detection (SN: 11/21/20, p. 16). “Based on reanalyses of the data, one of those groups suggests the phosphine signal actually was sulfur dioxide. That would mean there’s no reason to get excited about possible life signs — at least not yet,” Grossman says. The theory that microbes can travel from planet to planet, either by hitching a ride on spacecraft or by some other means, is gaining traction among some scientists. Recent evidence suggests some Earth microbes are hardy enough to make such journeys (SN: 9/26/20, p. 10).

Cosmic connections

Magnetized corpses of stars could be a source of fast radio bursts and high-energy neutrinos, Lisa Grossman reported in “Magnetars could solve dual mystery” (SN: 10/10/20 & 10/24/20, p. 8).

Reader James Ash wondered how neutrinos interact with another mysterious phenomenon: high-energy cosmic rays.

Neutrinos are nearly massless s­ubatomic particles with no electric charge. That means they rarely interact with normal matter, including cosmic rays — a type of charged particle with mass, Grossman says. But the two are connected, produced in tandem by energetic celestial objects. Similar to how magnetars might produce both fast radio bursts and high-energy neutrinos, evidence suggests bright galaxies called blazars eject both high-energy cosmic rays and high-energy neutrinos (SN: 8/4/18, p. 6).

Editor’s note

On October 29, Scientific Reports retracted the study described in “M­outhbrooder lives in the deep” (SN: 4/11/20, p. 12) at the researchers’ request. Eggs found in the mouth of a deep-sea fish species, Parazen pacificus, belonged to a species of crab — not the fish, a reanalysis of the eggs confirmed. Though P. pacificus appears to possess traits that suggest it could house fertilized eggs and perhaps hatchlings in the mouth, “the original data is not sufficient to confirm that this species is a mouthbrooder,” ichthyologist Randy Singer of the University of Michigan in Ann Arbor and colleagues wrote in the retraction.

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