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Planeten Venus
Venus is almost as big as the Earth and with almost as much mass.
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Scientist on possible life on Venus: "Completely unexpected"

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Almost 50 years ago, David Bowie released the song "Life on Mars". Now it turns out that it may be on the planet Venus that life first will be found. Something that pleases Andreas Johnsson, who is researching life on Mars.

"It feels really great, nonetheless! I think both of these planets have incredibly fascinating stories to tell, stories that are etched in stone and landscapes. On both Mars and Venus, scientists have now discovered gases that could potentially indicate life. Phosphine on Venus and a few years ago, methane on Mars," says Andreas Johnsson, geomorphologist with the planet Mars as his specialty.

It is an international research team that in a new study writes that they discovered concentrations of the molecule phosphine in Venus' atmosphere. The discovery was made in cloud layers at high altitudes where temperature and pressure are similar to those of the Earth's surface. Because phosphine on Earth is a product of biological activity, the discovery may be a sign of microbial life in Venus' atmosphere. Further research is needed to understand the origin of phosphine.

"If the phosphine turns out to come from organisms, it is most likely airborne bacteria with a life cycle that follows the circulation pattern of the atmosphere. The discovery will focus more on Venus for some time to come. And hopefully new probes and landers will be sent out to take a closer look at the phosphine and the composition and structure of the atmosphere."

Venus no previous candidate for life

According to Andreas Johnsson, the discovery of phosphine is great news because it was completely unexpected. Venus has been a bit under the radar as a suitable celestial body for life and the focus has rather been on Mars and the outer solar system moons, such as Europe and Enceladus.

"Venus, however, has an incredibly fascinating geological history. It is almost as big as the Earth and with almost as much mass. Venus may have been favourable to water and life early in its evolution, but traces of the young Venus are shrouded in obscurity."

The reason is that the entire surface of Venus was transformed 600-800 million years ago by globally extensive volcanism. By comparison, at the same time the Earth had developed multicellular organisms and animals were on the verge of settling on land. 

"This is pure speculation. But perhaps Venus evolved life according to the same pattern as on Earth, life that then succumbed when this cataclysm hit the planet. If a certain microbial life, after all, managed this dramatic change, the area where the phosphine was discovered is a suitable place, in protection from the extreme heat in the lower part of the atmosphere. That makes the discovery really exciting."

Much remains before answers about life on the neighboring planets

On Mars, the discovery of methane in 2013 caused a great sensation because methane on Earth largely has a biological origin, but where geological processes can also form it, independent of life. Now the scientific challenge is to try to understand the origin of these gases on each planet.

"If in the future we can prove with certainty that life exists on Venus and or Mars, then the next step will be to investigate the relationship with life on Earth. If it is not related to us, it would be a scientific find with no equivalence in history. Then we know that life can arise on other celestial bodies and the universe could therefore be teeming with different life forms."

Finally, in 1971, David Bowie released the song "Life on Mars". Who do you think will release the song Life on Venus?

"I have googled that 22 bands already have a song called "Life on Venus", but no one has had the success that Bowie had with Mars. Maybe it will change now? I hope that some Swedish metal band, maybe Ghost or Arch Enemy, will take on this important task."

Text: Thomas Melin och Ulrika Lundin

More information

Geomorphology is an academic discipline developed within the boundary area between geology and geography. In geomorphology, landforms, the composition of the landscape and the surface processes on Earth and other planets that form these landforms, are studied.

The article Phosphine gas in the cloud decks of Venus is published in Nature Astronomy.