Possible life in the atmosphere of Venus: how do you find extraterrestrial life? | NOW

Scientists announced on Monday that chemicals have been found in Venus’ atmosphere that indicate that the planet could support life. “I wouldn’t immediately think of Venus as a place of life,” says astrobiologist Floris van der Tak, who works at the SRON space research institute, in conversation with NU.nl. “But it doesn’t seem impossible to me.” How do we find that alien life?

In the atmosphere of the second-innermost planet in the solar system is phosphine found it. We only know this substance on earth in the emissions from factories or from micro-organisms. A specific source of the phosphine has not yet been found. It may be a sign of life on Venus.

Astrobiologist Van der Tak explains that the conditions on Venus are tough for life forms. “After all, it is very hot on the surface and the air pressure is very high.” But he adds that life is much more than just plants and animals. “And some bacteria can take a lot.”

This makes it perhaps unexpected for Van der Tak, but not impossible that there is life on Venus, so also elsewhere in the solar system than just on earth. But how do we find life on other planets?

Search for traces of life as known on Earth

“When we look for life on other celestial bodies, we usually look for traces of life as we know it on earth,” explains Van der Tak. This is done because otherwise astronomers would not know which tracks to follow.

Phosphine is therefore a molecule that we know as a possible emission of a micro-organism. This allows researchers to use it as an indicator of life. Another trace of possible life is (liquid) water, or oxygen.

People also use special equipment to search for radio signals. However, this has not yet paid off. “If there were extraterrestrial civilizations that emit radio signals, we might have already discovered them,” said Van der Tak.

The CHIME is a Canadian radio telescope that scans space for signals. (Photo: CHIME)

Venus joins celestial bodies in solar system with potential for life

There has long been speculation about life in the atmosphere of Venus, but with the discovery of phosphine, a trace of it may have been discovered now. This means that Venus is not the only celestial body in the solar system where we suspect that life could have been or has been, says Van der Tak.

For example, humans have been researching life on Mars since the nineteenth century. A year ago, scientists stated that (microscopic) Martians might have about the red planet flying around on dust particles. NASA uses various vehicles, such as the recently launched Perseverance rover, to search for traces of (former) life on the red planet.

There are also a number of moons in our solar system that may have the necessary building blocks for life. The moons Europa and Enceladus, orbiting Jupiter and Saturn respectively, are covered with a thick crust of ice. Underneath those ice crusts may be hidden liquid oceans, which could harbor life.

‘Great chance of life elsewhere in the universe’

The chance that (microscopic) life can be found outside our solar system is very high, according to Van der Tak. “Our sun and earth are not special celestial bodies. So there is a good chance that there are more of them, which may therefore harbor living beings.”

The first life on earth also arose relatively early. Earth was created about 4.5 billion years ago. The first bacteria followed about half a billion years later. “The chance that this process has already taken place elsewhere in the universe seems quite high,” says the astrobiologist.


Enceladus’ ice crust may be hiding an ocean of alien life. (Photo: NASA / JPL-Caltech / Space Science Institute)

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