Is there life on Venus?

Gas in clouds may be from aliens (well, microbes...)

‘It used to be a lot more habitable’

IT’S ferociously hot, the winds blow at 220mph and the toxic atmosphere is so heavy it would crush a human being in an instant.

So Venus has long been ruled out as a potential home for life. Instead, our other neighbour, Mars, has been the focus of the scientists’ investigations.

But now, however, they may have to think again. Astronomers have picked up a signal from a gas in the clouds above the planet which may have been belched out by hardy microbes.

Before it was wrecked by extreme global warming and temperatures hit as high as 462C (864F), Venus’s climate may have been similar to that of Earth.

Experts believe microbes from that time may have hung on, floating up to 38 miles into the clouds where it is a much more pleasant 20C (68F).

This theory is based on a gas called phosphine, which on Earth is produced by bacteria which typically do not need oxygen. It is sometimes found in animal guts and lake sediments. Phosphine was detected in the cloud deck above Venus by the light it absorbed, causing an interruption in the light signal from the planet.

The ‘V-shaped dip’ in the light was picked up by the James Clerk Maxwell Telescope in Hawaii, and the Atacama Large Millimeter/ submillimeter Array in Chile.

The team of researchers reporting the finding, led by Cardiff University, are not certain it is a sign of life. But they have ruled out other sources for the gas, including sunlight, lightning and volcanoes, suggesting these would have produced, at most, a ten thousandth of the amount of phosphine detected.

Professor Jane Greaves, from Cardiff University, who observed the light signal, said: ‘We have detected a rare gas called phosthere phine in the atmosphere of our neighbour planet Venus, and the reason for our excitement is that phosphine gas on Earth is made by micro-organisms that live in oxygen-free environments. And so is a chance that we have detected some kind of living organisms in the clouds of Venus.’

Dr Emily Drabek-Maunder, from the Royal Observatory in Greenwich, one of the team behind the analysis of the signal from Venus, said: ‘For two billion years the planet was a lot more habitable than it is now. It is certainly possible that phosphine comes from microbes that migrated upwards into the clouds.

‘However more study needs to be done before we can figure out the true cause for phosphine gas in Venus’s atmosphere.’

The sticking point for the life on

Venus theory is that those clouds are highly acidic, and in such conditions phosphine could be destroyed very quickly.

Professor Alan Duffy, lead scientist of The Royal Institution of Australia, said: ‘This is one of the most exciting signs of the possible presence of life beyond Earth I have ever seen, and certainly from the most surprising location I could imagine.’

David Rothery, professor of planetary geosciences at The Open University, said the work showed that the concentration of phosphine in Venus’s atmosphere was ‘too high to be simply explained.’