NASA may have found signs of life on Venus in 1978 without realizing

If life does exist on Venus, NASA may have first detected it back in 1978. But the finding went unnoticed for 42 years.

Life on Venus continues to be an extended shot. But there’s reason to require the concept seriously. On Sept. 14, a team of scientists made a bombshell announcement within the journal Nature Astronomy: Using telescopes, they’d detected phosphine, a toxic gas long proposed as a possible sign of alien microbial life, within the upper a part of the planet’s thick atmosphere. The detection was a landmark within the long look for life elsewhere within the scheme, which has mostly focused attention on Mars and some moons orbiting Jupiter and Saturn. Meanwhile, Venus, hot and poisonous, was long considered too inhospitable for all the world to survive. But now, digging through archival NASA data, Rakesh Mogul, a biochemist at Cal Poly Pomona in California, and colleagues have found a touch of phosphine picked up by Pioneer 13 — an inquiry that reached Venus in December 1978.

“When the [Nature Astronomy paper] came out, I immediately thought of the legacy mass spectra,” Mogul told Live Science.

Mogul and his coauthors were broadly aware of the information from the missions, he said. “So, for us, it absolutely was a natural next step to convey the information another look.  As such, after consulting with my co-authors, we identified the initial scientific articles, and promptly started searching for phosphorous compounds.”

The discovery, published to the arXiv database Sept. 22 and not yet peer-reviewed, doesn’t tell researchers much beyond what was reported in Nature Astronomy — though it does make the presence of phosphine (made of a phosphorus atom and three hydrogens) even more certain, they said. The 1978 data comes from the big Probe Neutral spectroscope (LNMS), one in all several instruments that descended into Venus’ atmosphere as a part of the Pioneer 13 mission. 

An image shows how Pioneer-13’s Large Probe, which carried the LNMS, may need to look at because it plunged through Venus’s clouds.

An image shows how Pioneer-13's Large Probe, which carried the LNMS, might have looked as it plunged through Venus's clouds.

An image shows how Pioneer 13’s large probe, which carried the LNMS, might have looked as it plunged through Venus’s clouds. (Image credit: NASA)

Pioneer 13 dropped an oversized probe (the LNMS) into Venus’ clouds; suspended from a parachute, the probe collected data and beamed it back to Earth because it plummeted toward its robotic death. (Three smaller probes also dropped from Pioneer 13 without parachutes.) The LNMS sampled the atmosphere and ran those samples through mass spectrometry, a typical lab technique accustomed to identify unknown chemicals. When scientists first described the LNMS leads to the 1970s, they didn’t discuss phosphorus-based compounds like phosphine, focusing instead on other chemicals.

When Mogul’s team reexamined the LNMS data from Venus’ lower and middle clouds (a potentially habitable zone on the planet), they found signals that look a good deal like phosphine, the researchers wrote. The scientists also found definitive evidence for atoms of phosphorus within the atmosphere, which likely came from a heavier gas like phosphine.

LNMS wasn’t built to hunt phosphine-like compounds and would have had a tough time distinguishing the gas from other molecules that have similar masses. But Pioneer 13’s sample did have evidence of some molecule present within the gas that had the identical mass as phosphine — in amounts that match the amount described within the Nature Astronomy paper.

“I believe that evidence for [trace chemicals that would be signatures of life] within the legacy data was a form of discounted because it absolutely was thought that they might not exist within the atmosphere,” Mogul said. “I think many of us are now revisiting the notion of Venus as a completely oxidizing environment.” (A “fully oxidizing environment” wouldn’t include phosphine or most other chemicals seen as signs of life.)

Mogul and his colleagues also found hints of other chemicals that shouldn’t arise naturally in Venus’ clouds — substances like chlorine, oxygen, and peroxide.

“We believe this to be a sign of chemistries not yet discovered,” they wrote, “and/or chemistries potentially favorable always.”

What’s needed, they wrote, is further, sustained exploration of Venus.

“We need a more sustained approach for exploration like that of Mars,” Mogul said.

NASA and also the European, Indian and Russian space agencies have plans for Venus probes that may be helpful, he said. 

“However, when considering the past, current, and future habitability of Venus, we might need longer-term chemical and geology studies to grasp the sources of any potential chemical [anomalies] within the clouds,” he said. “This can be from orbital probes, balloon-suspended probes within the clouds, and/or heat-stable lander probes.”

The phrase “heat-stable” is vital, given the planet’s habit of killing any robot that lands on its sizzling hot surface.