Scientists find possible life on Venus

Morning star: Venus is one of the brightest objects in the sky, often visible in broad daylight.© NASA

Is there life on our neighbouring planet? A gas detected floating in the clouds above Venus could hold the key to extra-terrestrial life quite unlike anything we have ever imagined.

It’s not at the top of the list when thinking of life elsewhere in our solar system. Indeed, compared to Earth, Venus is hellish – a barren wasteland of scorching heat and thick clouds filled with sulphuric acid.

But traces of a pungent gas wafting through the clouds could be proof of extra-terrestrial life, according to a study published this week.

Long considered Earth’s twin, Venus is about the same size as our home planet, having a similar gravity and composition. For two billion years, it has been considered as temperate, harbouring at least one ocean. But today, the planet has experienced extreme global warming. Carbon dioxide makes up 96% of the atmosphere and temperatures reach up to 450°C.

Far above the surface, though, the weather is cooler. It is here, in the clouds, that a group of researchers has detected phosphine.

This is a molecule made up of one phosphorus atom and three hydrogen atoms. Used as a chemical weapon during World War I, it is still manufactured as an agricultural fumigant.

It is also produced in oxygen-starved environments such as swamps, marshlands and even animals’ innards. As far as we know, on rocky planets such as Earth, it can only be made by life – whether human or microbe.

“Finding a gas like this on Venus is really exciting because of the possibility that it could also have been produced by life, as on Earth,” explained Dr Emily Drabek-Maunder, one of the scientists from the team.

When they first spotted the phosphine back in 2017, it was so unlikely that the team thought they must have made an error. “I immediately freaked out,” said Clara Sousa-Silva, co-author of the study. “I presumed it was a mistake.” But in 2019, they confirmed the discovery using Chile’s Alma telescope.

Phosphine can be produced in volcanic eruptions and lightning strikes, but these events would never be able to produce the amount of gas detected above Venus.

Now, the authors of the study have published their data and are appealing to others for suggestions about the origins of the gas. Individuals from around the world are already contributing. Planetary scientist Sara Seager has suggested a whole life cycle of Venusian microbes.

Meanwhile, Charles Cockell from Edinburgh University remains sceptical. He warns that a biological explanation should always be a “last resort”, adding that “there are good reasons to think the Venusian clouds are dead”.

All agree that, if life does exist, it would be very different from anything we have previously seen. Venus clouds are made up of over 75% sulphuric acid; any microbe capable of surviving in such extreme conditions would a radically different biological structure.

So, should we be optimistic about finding alien life?

Anybody there?

Probably not, say some. The probability that anything could live in the sulphur-heavy clouds above Venus is extremely low. The phosphine is most likely a product of some unknown natural reaction we have yet to discover. Besides, scientists have been searching for centuries and found nothing. We should admit that the universe is a lonely place and be grateful to have our homes here.

Let’s not give up, say others. We should be hopeful about finding other life in our universe. This discovery on Venus is a good sign. It suggests that we may be closer than we think to finding extra-terrestrial life, and provides us with new ideas about where to look. Aliens might not be quite as we have imagined them, but our chances of finding them seem higher than ever.

You Decide

  1. Will scientists ever find intelligent civilisations on other planets?
  2. If intelligent life does exist, would it be wise to make contact with the aliens?

Activities

  1. Draw a map of our solar system. Find a fact about each planet and add them to your diagram.
  2. Imagine you have met a friendly alien. Think of 10 questions to ask about its home planet, and 10 essential things to tell it about ours.

Some People Say...

“Two possibilities exist: either we are alone in the Universe or we are not. Both are equally terrifying.”

Arthur C Clarke (1917–2008), British science-fiction writer

What do you think?

Q & A

What do we know?
It is generally thought that alien life exists on other planets. While it is possible that we may be alone in the universe, most astrobiologists consider this highly unlikely. There are an estimated six billion Earth-like planets in our galaxy alone, and there may be as many as two trillion galaxies in the universe. To be considered Earth-like, a planet must by rocky and orbit a Sun-like star at a habitable distance that can host liquid water and potentially life.
What do we not know?
One main area of debate is why – if there are a huge number of potentially inhabited planets – we have seen no signs of alien life before. The question is known as the Fermi Paradox after the physicist who first post it. Those who think it is because the aliens cannot make contact ware called Cantians (as in the word “can’t”). Those who believe they simply choose not to are called Wontians (as in the word “won’t”).

Word Watch

Sulphuric acid
A mineral acid composed of sulphur, oxygen and hydrogen. The clouds above Venus contain around 75% sulphuric acid, which is corrosive and highly poisonous to any living being from Earth.
Temperate
A climate with tepid temperatures comfortable for life. In the clouds above Venus’s surface, temperatures range between minus 1 and 90°C, a far more habitable climate than the scorching temperatures on land.
Chemical weapon
The gas is extremely poisonous and was released by armies during the war to attack the enemy. It was responsible for around 85,000 deaths.
Fumigant
A chemical that produces fumes to disinfect or purify an area. In agriculture, fumigants are used for pest control.
Spotted
Scientists detected the gas while observing the planet with the James Clerk Maxwell telescope, the largest astronomical telescope in the world.
Alma
A powerful telescope designed to observe molecular gas and dust, and therefore a brilliant tool for studying the atmosphere on Venus from a distance.
Venusian
In science fiction, a person or being living on Venus. It is used to describe anything native to the planet.

Subjects

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