Venus, the second closest planet to the sun and the planet which comes the closest to Earth (Credit: NASA/JPL-Caltech)

Our Next Door Neighbours

On the Detection of Phosphine and the Possibility of Life on Venus

The Ingredients for Life

Before we even consider the existence of life, we need to determine if it is even possible for it to even survive on Venus. In general, for planets to be a potential host for life as we know it, it must have 3 vital ingredients.

💧 Water

One of the guiding policies in the search for alien life is “follow the water”. Why? Well, water does it all. Not only does it support cell structure, but it also acts as a universal solvent. This allows it to transport a variety of important chemicals in cells and remove waste. Water’s many unique qualities make it vital for life as we know it.

🧪 Chemistry

A certain 6 elements make up all of life on earth: carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur (CHNOPS). These elements exist in great abundance in the universe and account for 97% of our bodies. Especially important is carbon, the building block of life as we know it. Carbon bonds easily with a variety of atoms, allowing it to form tons of different compounds. In fact, carbon forms more compounds than all the other elements put together.

⚡️ Energy

All life uses energy to drive chemical reactions and fuel processes essential for their survival. This includes the break-up, transport and assembling of molecules. On Earth, all energy comes directly or indirectly from the sun. Plants use energy from the sun for photosynthesis, converting water and carbon dioxide to glucose to use for energy, and releasing oxygen as a byproduct.

Venus, the Goddess of… Love?

Being outside the habitable zone of our sun, the Earth-sized planet is often described as hellish, and with good reason. However, research suggests that Venus was once home to an ocean of liquid water on its surface, and was very similar to Earth for 2 billion years of its history. How could these 2 planets go on such different paths? The answer lies in Venus’s atmosphere.


Armed with the JCMT and ALMA radio telescopes, the team detected the absorption at a specific wavelength which can only be explained by the presence of phosphine. The data suggests a phosphine concentration of 20 parts per billion in the atmosphere of Venus, 1,000 to a million times larger than found in Earth’s atmosphere.

An artist’s depiction of phosphine molecules in the Venusian atmosphere (Credit: © ESO/M. Kornmesser/L. Calçada & NASA/JPL-Caltech, (CC BY 4.0))
The phosphine molecule, consisting of 1 phosphorus atom (orange) and 3 hydrogen atoms (white)

None of these potential phosphine production pathways are sufficient to explain the presence of ppb phosphine levels on Venus” — Bains et al.

Yes, NONE of these methods produces enough phosphine to explain the amount found in the Venusian atmosphere. In other words, we have no idea where the phosphine is coming from.

Life in the Clouds

Although astronomers had recently focused on Mars and moons in the outer solar system, Venus has not entirely been neglected in the search for life. The idea of life in the clouds of Venus has floated around (pun intended) for quite some time. In 1967, astrobiologist Harold Morowitz and famous astronomer Carl Sagan speculated that there may be life in the clouds of Venus.

An illustration of the layers of atmosphere on Venus. (Credit: Seager et al. 2020)

Next Steps

Before getting too far ahead of ourselves, we need to first confirm that there actually is phosphine in the clouds of Venus. On Earth, astronomers are now following up on the detection to see if they can replicate the results observed by Greaves and her team, and to use different parts of the spectrum to see if they can get other absorption lines associated with phosphine.

Artist’s impression of the ESA and JAXA’s BepiColombo spacecraft, one of the missions scheduled to fly by Venus in the next few months. (Credit: ESA)

New Questions

The potential of life on Venus raises many intriguing questions. How did life get there? Is this life relatively new, emerging within the past few thousand years? Or is it ancient life, evolved from the once possibly habitable Venus from billions of years ago? If so, is life on Earth somehow related to Venusian life? Or, is it a completely different form of life, unknown to humans? Is there more life in our solar system? Our galaxy?

Learn More

A great episode of StarTalk, answering many questions relating to life on Venus.



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