Scientists detect potential signs of extraterrestrial life on Venus

According to the study's co-author Clara Sousa-Silva, the most plausible explanation for finding phosphine on Venus is the existence of extraterrestrial life.

Sep 15, 2020 14:13 IST
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Scientists revealed on September 14, 2020 that they have detected potential signs on life on the inhospitable Venus. The scientists have detected a gas called phosphine in the acidic clouds of Venus that indicates microbes may inhabit Earth’s neighbor.

Though the researchers did not discover actual life forms, this discovery raises hopes of potential life beyond Earth. The researchers noted that phosphine is produced by bacteria thriving in oxygen-starved environments on the Earth. 

The presence of Phosphine was first spotted in Venus clouds by an international scientific team using the James Clerk Maxwell Telescope in Hawaii. The researchers later confirmed the discovery using the ALMA (Atacama Large Millimeter/submillimeter Array) radio telescope in Chile.

The study was published in the scientific journal - Nature Astronomy. The lead author of the study, astronomer Jane Greaves from Cardiff University said, "I was very surprised - stunned, in fact.”

NASA Administrator Jim Bridenstine tweeted saying that the discovery of phosphine is the most significant development yet in building the case for life off Earth.” He further added that it is time to prioritize Venus. 

What does the discovery mean?

According to the study's co-author Clara Sousa-Silva, the most plausible explanation for finding phosphine on Venus is the existence of extraterrestrial life. Sousa-Silva is a molecular astrophysicist at the Massachusetts Institute of Technology.

Sousa-Silva continued by saying that life, as an explanation for their discovery, should be, as always, the last resort. She further explained saying that this is important because, "if it is phosphine, and if it is life, it means that we are not alone." 

She added saying that it means that life itself must be very common and there must be many other inhabited planets throughout our galaxy.

What is Phosphine?

Phosphine is a flammable, colorless and explosive gas at ambient temperature that has the odor of garlic or decaying fish.

Presence of Phosphine on Venus

• Phosphine was detected in the temperate zone of Venus' atmosphere at an altitude of about 50 km at 20 parts-per-billion, a concentration which is not possible with known chemical processes, as Venus lacks the high temperatures and pressures to form phosphine the way other gas giants like Jupiter do.

The study states that the possible explanations for the presence of phosphine on Venus could be some unknown photochemistry or geochemistry or going by the analogy of biological production of PH3 on Earth- it could be from the presence of life. The study's lead author Jane Greaves revealed that the researchers examined potential non-biological sources such as volcanism, meteorites, lightning and various types of chemical reactions, but none appeared viable.

As per the researchers, it is not possible that phosphine would persist in the Venusian atmosphere, as it would eventually be consumed by water and carbon dioxide after being subjected to ultraviolet radiation. This means that it would have to be replenished.

On the Earth, phosphine is produced by microorganisms in “anaerobic” environments - an ecosystem that does not rely on oxygen such as swamps, sewage plants, rice fields, marshlands, lake sediments and excrements and intestinal tracts of animals. Phosphine is also produced non-biologically in certain industrial settings. 

Research is currently continuing to either confirm the presence of life on Venus or find an alternative explanation.

Potential signs of Extraterrestrial Life

The existence of extraterrestrial life has been one of the paramount questions of science ever since space studies were undertaken. Scientists have used probes and telescopes to seek “biosignatures” or indirect signs of life on other planets and moons in our solar system and beyond.

However, Venus had never been the focus of the search for life in our solar system. Planets like Mars and other worlds have been largely the focal point for detecting potential signs of extraterrestrial life.

Why is Venus inhospitable?

•  Venus, the second planet from the Sun and Earth’s closest planetary neighbor, has a structure that is similar but slightly smaller than Earth. The planet is known to be wrapped in a thick, toxic atmosphere that traps heat. The surface temperatures of Venus are known to reach till about 471 degrees Celsius, which is hot enough to melt lead. Hence, the planet is regarded inhospitable as no life would be able to survive on the surface of Venus.

•  According to the study's co-author Clara Sousa-Silva, Venus could have had life on its surface a long time ago before a runaway greenhouse effect left the majority of the planet completely uninhabitable. She further stated that she can only speculate on what life might survive on Venus if indeed it is there.

•  She added saying that if it is microorganisms, they would have access to some sunlight and water and maybe live in liquid droplets to stop themselves dehydrating, but they would need some unknown mechanism to protect against corrosion by acid.

•  As per the study, Venus should be hostile to phosphine as its surface and atmosphere are rich in oxygen compounds that would rapidly react with and destroy phosphine. Hence, according to another study co-author Anita Richards, “Something must be creating the phosphine on Venus as fast as it is being destroyed.” Richards is an astrophysicist associated with the University of Manchester in England.


In the past, scientists have suspected that the Venusian high clouds with mild temperatures around 30 degrees Celsius could host aerial microbes that could endure extreme acidity. These clouds are made up of 90 percent sulphuric acid. The earth microbes could not survive the high level of acidity.

A new space probe to Venus may be needed to confirm the presence of life on the planet. The latest study may bring a huge shift in the international strategy to find traces of extraterrestrial life. 

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