Have We Found Life on Venus?

Venus represents second planet from Sun sometimes called Earth’s twin due to nearly identical size and mass with both possessing significant atmospheres suggesting planets should be very much alike despite dramatic differences.

Venus represents toxic hellscape compared to Earth featuring extreme temperatures exceeding 400 degrees Celsius, crushing atmospheric pressure more than 90 times higher than Earth, and monstrously thick atmosphere containing poison sulfuric acid clouds.

Crushing pressure and immense heat make Venus particularly hard place to explore resulting in no Venus rover ever deployed with longest surface mission being stationary lander surviving only two hours before succumbing to conditions.

Carl Sagan wrote 1967 that while Venus surface conditions make life hypothesis implausible the clouds of Venus represent different story altogether proposing alternative habitat decades before phosphine discovery potentially supporting this prescient hypothesis.

Phosphine gas represents substance known on Earth as something to be avoided being colorless, flammable, and very toxic gas with chemical formula PH3 used historically as chemical weapon and currently as agricultural fumigant.

Phosphine can be byproduct of life specifically from some species of anaerobic bacteria representing organisms living in environments with no oxygen such as marshes, landfills, or inside animal guts producing phosphine through metabolic processes.

Scientists determined phosphine to be appropriate biosignature gas earlier in 2020 representing gases produced by life that accumulate in atmospheres to detectable levels helping guide scientists in quest of looking for life on other planets.

Biosignature gases represent those produced by life that accumulate in planetary atmospheres to detectable levels helping guide scientists in their quest of looking for life on other planets through remote atmospheric analysis.

On Earth majority of life centered around oxygen representing byproduct of photosynthesis subsequently used by other life forms to breathe with methane and nitrous oxide also among Earth’s biosignature gases indicating biological activity.

Phosphine takes extremely specific thermodynamic conditions to form outside biological life requiring extremely high temperatures and plenty of elemental hydrogen with scientists knowing no way phosphine can be produced on planets below 527 degrees Celsius.

Gas giant Jupiter possesses high levels of phosphine gas formed in hottest deepest atmosphere layers where hydrogen abundant demonstrating abiotic phosphine production possible under extreme gas giant conditions unlike rocky planets.

Researchers pointing ALMA telescope array at Venus almost could not believe detection discovering far more phosphine than even exists on Earth at 20 parts per billion versus Earth’s 7 parts per trillion representing extraordinary and unexpected finding.

Venus phosphine detected at 20 parts per billion concentration far exceeding Earth’s approximately 7 parts per trillion representing roughly thousand-fold higher abundance despite Earth having known biological phosphine sources.

Most life origin theories include common set of environmental conditions considered vital: liquid water to dissolve molecules, mild temperatures below 122°C to preserve organics, concentration processes, complex diverse environments, and trace metals promoting organic formation.

Venus current conditions seem unlikely for giving rise to life with surface temperatures over 400 degrees Celsius meaning no liquid water can be present and heat would also break down any organic molecules making surface inhospitable.

Carl Sagan postulated 1960s that going up to middle of Venus cloud layer temperatures and pressures become rather Earth-like where water droplets could form and electric discharge in clouds could possibly lead to organic molecule formation.

Cloud life theory falls apart quickly when considering clouds made of sulfuric acid where hyper-acidic environment would break down any free-floating organic compounds making Venus today no place for life to form despite temperate cloud conditions.

Recent computer modeling shows early Venus very similar to early Earth with shallow oceans and mild temperatures for up to two billion years of early history suggesting planet may have been habitable before runaway greenhouse transformed conditions.

Researchers propose if phosphine indicates life this life represents relic of previous biosphere being ancient remnant of once thriving ecosystem that collapsed due to runaway greenhouse effect with life adapting to spread into clouds when climate change boiled oceans.

Researchers 2005 used balloon to collect samples from different levels of Earth’s stratosphere at heights ranging 20 to 41 kilometers detecting 12 bacterial and 6 fungal colonies with microbes from every major biological lineage now detected in upper atmosphere.

Even most durable extremophiles living in acidic conditions on Earth can withstand only around 5 percent acid while Venus cloud conditions exceed 90 percent acid representing environmental extreme far beyond known biological tolerance also ruling out accidental Earth microbe contamination.

Supposed alien life living in Venus environment would have to exist in some form unknown to us either somehow withstanding or protecting their carbon bonds from acid or existing as non-carbon-based life-forms with different chemical bonds altogether.

Researchers carefully examined other possible phosphine origins noting while lightning can occur on Venus it happens much less than on Earth and would fall short of producing energy required to create detected phosphine levels.

Researchers estimated needing more than 200 times as much volcanic activity on Venus as on Earth to inject enough phosphine into atmosphere to be detectable and while thousands of volcanoes exist on Venus none apparently active with maximum volcanic phosphine production at least seven orders of magnitude too low.

Assuming Venus receives same meteorite amount as Earth per year would deliver negligible phosphorus since meteorites contain average 0.25 percent phosphorus by weight and conservatively assuming 100 percent conversion these meteors would deliver maximum around 10 tons phosphine yearly insufficient for detection.

Supposed alien life living in Venus sulfuric acid environment would exist in form unknown to science either somehow withstanding or protecting carbon bonds from acid breakdown or existing as non-carbon-based life-forms with different chemical bonds altogether.

Scientists doubt phosphine detection itself even real noting signal detected was faint and extensive amount of processing needed to pull it from telescope data with processing potentially returning artificial signal at same frequency as phosphine.

Researchers repeated their findings on two different telescope arrays the James Clerk Maxwell Telescope and ALMA finding nearly identical pattern of detection addressing skepticism and strengthening confidence in phosphine signal authenticity.

If researchers confirm phosphine detection beyond shadow of doubt and continue unable to explain it next step will require sending spacecraft to Venus to check exactly what is going on collecting gas samples or even possible alien life.

As Carl Sagan once said extraordinary claims require extraordinary evidence and as planetary science community sets priorities for next decade of space exploration Venus has rocketed to front of list demanding rigorous investigation before accepting life claims.

Even authors of paper emphasize detection of phosphine not robust evidence for life only for anomalous and unexplained chemistry remaining after exhausting known abiotic production pathways leaving mystery requiring further investigation.