A year after the discovery of phosphine gas in the atmosphere of Venus, a signal many believe could be indications of microscopic life, the research team behind the controversial discovery have reexamined the data. And, they say, this reanalysis only reaffirms their original conclusions.
BACKGROUND: PHOSPHINE AND EXTREMOPHILES
On Earth, most living things expel carbon dioxide or oxygen into the atmosphere. However, certain types of organisms living in extreme environments, dubbed “extremophiles,” can expel a type of phosphorus gas known as phosphine. In 2020, researchers studying data from a pair of large telescopes found the telltale signature of this gas in the Venusian atmosphere, and in concentrations that seemed to indicate the presence of such phosphine belching life.
“The chemical phosphine (PH3) is a considered a biomarker because it seems so hard to create from routine chemical processes thought to occur on or around a rocky world such as Venus,” explains a post by NASA.
This discovery set off a wave of reactions, from outright excitement that signs of extraterrestrial life had been found, to doubts that the signal of phosphine was even detected in the first place.
ANALYSIS: ANOTHER LOOK AT THE DATA REAFFIRMS INITIAL RESULT
In an attempt to resolve the issue, at least as much as possible before on-site measurements by future probes can answer the question once and for all, the original research team behind the controversial results have taken a fresh look at the data. And what they found seems to support their original conclusion.
“A reanalysis of the legacy data collected by the NASA Pioneer Venus Neutral Gas Mass Spectrometer (LNMS) (13) at the altitude of 51.3 km shows evidence of PH3 in the clouds of Venus,” explains the post by the researchers.
Furthermore, they note that “PH3 (phosphine) is the only P-containing molecule that fits the data and is in gas form at Venus’ 51.3 km altitude.”
This is pretty dispositive, the researchers note, because “+P does not overlap with any other neutral gas mass fragment expected from the Venus atmosphere, giving +P a unique and robust detection.”
Feeling confident in their conclusion, the result then underwent further confirmation, including the elimination of a possible false signal from a naturally occurring process.
“One might argue there could be a very tiny amount of, e.g., phosphoric acid vapor that could have fragmented into +P,” the researchers postulate, “but the corroborating acid fragmentation ions were not detected and should have been.”
In the end, the research team concluded; “We stand by the existence of Venus atmospheric phosphine, while acknowledging that the debate may never be settled until a return to in situ measurements in the Venus atmosphere.”
OUTLOOK: A CLOSER LOOK WILL ANSWER ALL
In June of 2021, NASA announced a pair of future missions to the fiery world, with both carrying instruments that can end the debate of phosphine once and for all. Dubbed “DAVINCI+” (Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging) and “VERITAS” (Venus Emissivity, Radio Science, InSAR, Topography, and Spectroscopy), the two announced missions are part of NASA’s Discovery program.
“Using cutting-edge technologies that NASA has developed and refined over many years of missions and technology programs, we’re ushering in a new decade of Venus to understand how an Earth-like planet can become a hothouse,” said NASA’s associate administrator for science Thomas Zurbuchen in a statement on the two new missions. “Our goals are profound. It is not just understanding the evolution of planets and habitability in our own solar system, but extending beyond these boundaries to exoplanets, an exciting and emerging area of research for NASA.”
Both DAVINCI+ and VERITAS are expected to launch around the end of this decade, so it may be a while before the question is definitively answered. However, given the detailed reanalysis of the original signal by the original research team, and those same researchers’ attempts to directly address each of the previous criticisms of their initial find, the options seem to be narrowing more and more toward the original find being a valid one.
Follow and connect with author Christopher Plain on Twitter: @plain_fiction