With its boiling temperatures and acidic clouds, it’s one of the most formidable worlds in our solar system

But exciting new findings suggest life may exist on Venus, the second planet from the sun.

Researchers have confirmed traces of ammonia and phosphine in the planet’s clouds – two potential ‘biomarkers’ that are indicative of life. 

On Earth, both compounds are produced during the decay of organic matter, such as plants and animals.   

Because there are currently no other known natural processes for its production on Venus, it could be being produced by something scientists aren’t aware of. 

Today, Venus is the warmest planet in the solar system, with a surface hot enough to melt lead and a thick atmosphere containing toxic clouds of sulfuric acid

What have experts found in Venus’ clouds?

  • Ammonia – on Earth produced by decay of plant and animal matter 
  • Phosphine – produced by microbes in the absence of O2 and released from decay of organic matter

(Phosphine was originally found in Venus’ clouds in 2020 but the findings were discredited) 

It follows the original detection of phosphine in Venus’ clouds in 2020 – although the findings were disputed

The new findings were presented at the National Astronomy Meeting 2024 at the University of Hull on Wednesday. 

Professor Jane Greaves, an astronomer at Cardiff University and author on the findings, said ammonia has been seen before in the solar system, but in the gas giant planets Jupiter and Saturn. 

‘It’s natural there because their gas is mostly hydrogen,’ she told MailOnline. 

‘It’s much rarer on the rocky planets like Earth or Venus.’ 

Ammonia is a colorless, poisonous gas that occurs in nature, primarily produced by anaerobic decay of plant and animal matter. 

Professor Greaves and colleagues detected the gas in Venusian clouds using the Green Bank telescope in West Virginia. 

The giant 2.3-acre dish detects weak radio waves that rain down on us from objects in space. 

‘In simple terms, the Green Bank telescope takes a rainbow of light except it does it in radio light,’ Professor Greaves said. 

‘Where there is some missing light, that’s because a molecule has mopped it up and we use the exact wavelength to identify the molecule.’ 

The ammonia was detected in the upper parts of the planet’s clouds where it’s too cold for life to exist. 

However, there is the possibility that the ammonia could also be in the deeper, warmer area of the clouds and is then rising to the upper parts. 

That will be what the researchers will try to establish next. 

Professor Greaves and colleagues detected ammonia there using the Green Bank telescope in West Virginia (pictured)
Thanks to its dense atmosphere, Venus is even hotter than planet Mercury even though the latter orbits closer to the sun

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Meanwhile, phosphine was discovered by a team led by Professor Greaves and Dr Dave Clements at Imperial College London’s physics department, by studying data from the James Clerk Maxwell telescope in Hawaii.

Phosphine, a colourless gas that smells like garlic or decaying fish, is naturally produced on Earth by certain microorganisms in the absence of oxygen. 

It can also be released in small amounts from the breakdown of organic matter, or industrially synthesised in chemical plants.

Dr Clements stressed that the detection of both these gases on Venus is not evidence that life exists there and it’s unknown what processes are emitting them. 

‘It is most likely some chemical process that we don’t currently understand and don’t know about,’ he told MailOnline. 

‘But phosphine has been proposed as a biomarker for exoplanets [planets outside our solar system], and on Earth it is only found in association with life, so life is also a possibility. 

‘At this stage we just don’t know – more observations and more lab and theoretical work is needed to understand what’s going on, and maybe future missions to Venus will help as well.’ 

Traces of phosphine gas detected in the clouds above Venus – seen here in an image taken by NASA’s Mariner 10 spacecraft – could be an indication that the planet supports microbial life

Venus: Earth’s ‘evil twin’

Diameter at the equator: 7,521 miles (12,104 km)

Distance from Earth: 24 million miles (38 million km)

Atmosphere: Mainly CO2 

Surface temperature: 464°C (867°F)

Surface pressure: 92 bar

Day length: 117 Earth days

Year length: 225 Earth days

Venus is known as Earth’s ‘evil twin’ because its also rocky and about the same size, but its average surface temperature is a blistering 870°F (465°C). 

Thanks to its dense atmosphere, Venus is even hotter than planet Mercury, even though the latter orbits closer to the sun.

The rocky sphere is not only inhospitable but also sterile – with a surface hot enough to melt lead and toxic clouds of sulfuric acid. 

Because the clouds are so acidic, the phosphine would be broken down very quickly and must therefore be being continually replenished. 

However, it’s generally believed in the astronomical community that the planet was not always such an unwelcoming place. 

Perhaps as recently as 700 million years ago, Venus likely had oceans similar to Earth’s – and could have harbored life as we know it today. 

But these oceans boiled away when our neighbouring planet underwent ‘a runaway greenhouse effect’ – a dramatic escalation in temperatures. 

Venus is known as Earth’s ‘evil twin’ because its also rocky and about the same size, but its average surface temperature is a blistering 870°F (465°C). Pictured, the surface of Venus, as interpreted by the Magellan spacecraft


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It was back in 2020 that scientists revealed traces of phosphine gas in the planet’s clouds which they said could be coming from microbes. 

At the time, Professor Greaves and colleagues observed Venus using both the James Clerk Maxwell Telescope at Hawaii’s Mauna Kea Observatory and the Atacama Large Millimeter/submillimeter Array in Chile. 

They detected a so-called ‘spectral signature’ that is unique to phosphine and estimated that the gas is present in Venus’ clouds in an abundance of around 20 parts-per-billion. 

However, other scientists claimed not to be able to find the same signal and members of Greaves’ team admitted to a calibration error and downgraded the strength of their claims.

Now, using the James Clerk Maxwell telescope once more, Dr Clements has been able to find phosphine again, and he thinks it may get destroyed by sunlight during the day.

Photograph of the James Clerk Maxwell Telescope on Mauna Kea, Hawaii (centre). To the left is the Caltech Submillimeter Observatory, and to the right is the Smithsonian Submillimeter Array

The UV in sunlight breaks the molecule up, which may explain why some observations have found phosphine while others have not,’ Dr Clements said. 

Dr Robert Massey, deputy executive director at the Royal Astronomical Society who wasn’t involved in the research, called the findings ‘very exciting’. 

‘But it must be stressed that the results are only preliminary and more work is needed to learn more about the presence of these two potential biomarkers in Venus’s clouds,’ he told MailOnline. 

‘Nevertheless, it is fascinating to think that these detections could point to either possible signs of life or some unknown chemical processes.

‘It will be interesting to see what further investigations unearth over the coming months and years.’ 

NASA scientist is ‘absolutely certain’ there is alien life in our Solar System – and reveals why extraterrestrials are most likely to be hiding on Venus 

A planet that suffers scorching 475°C (900°F) temperatures beneath a thick acidic atmosphere may be the last place you’d expect alien life in our Solar System.

But one NASA scientist claims that extraterrestrials are most likely hiding on Venus amid conditions that are unbearable for humans.

The theory was put forward by Dr Michelle Thaller, a research scientist at the US-based Goddard Space Flight Centre.

She says that ‘possible signs of life’ have already been seen within the carbon-dioxide filled atmosphere, adding that she was absolutely certain that life exists somewhere.

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