UPDATED
Everything you need to know about signs of life discovered on VenusAstronomers have detected a gas in Venus' atmosphere that suggests that the planet might be home to microbial life – one of the most exciting discoveries in recent years
By MATT REYNOLDS
Tuesday 15 September 2020
NASA/JPL-Caltech
Although Venus is the closest planet to Earth, it’s also one of the Solar System’s most under-loved residents. While Mars is inundated with orbiting problems and visits from rovers, at the moment Venus only has one spacecraft keeping it company – the Japanese probe Akatsuki.
That might all be about to change. On September 14 an international team of scientists announced that they had found what might be a sign of life floating in the atmosphere above Venus. After decades of searching fruitlessly for life on Mars, our next door neighbour has surprised us with one of the most promising indicators of life anywhere in the Solar System.
Here’s everything you need to know about one of the most exciting discoveries in the hunt for extraterrestrial life so far.
What’s all the fuss about?
Astronomers have detected a gas called phosphine in the clouds 50 kilometres above the surface of Venus. This is intriguing because we don’t know any non-biological way that phosphine could be made on Venus, which leaves open the possibility that tiny alien microbes in the planet’s atmosphere could be farting out the gas.
So it’s just a gas? I was hoping for something a little more tangible. A photo or something
Sorry about that. In scientific terms, this is a pretty promising signal though. On Earth phosphine is only made in the lab or by microorganisms and can be found in swamps as well as animal intestines. It’s present in large amounts on Jupiter and Saturn, but that’s because those planets have violent storms ideal for producing the gas and these conditions aren’t replicated anywhere else in the Solar System, as far as we know.
There are two other things that make the biological origin of phosphine a credible hypothesis. First, there’s quite a lot of it up there – about five to 20 parts per billion. That might sound tiny, but it’s thousands of times more than what you’d find in Earth’s atmosphere. Second, we know that phosphine is constantly being broken down by light so in order to detect it now it means that some process is constantly replenishing the phosphine in the atmosphere.
Does that mean it’s definitely being produced by life?
No – not by a long shot. What it does mean is that we don’t know any chemical or physical process that could be generating this gas on Venus, which leaves biological origins as a plausible answer. It could be all down to some chemical process that we just don’t understand yet.
Venus is a pretty niche choice for life. I thought Mars was where all the action is?
For decades, scientists have argued that Venus might be able to support life, but we haven’t tried very hard to check it out as attention has focused on Mars and the icy moons of Jupiter and Saturn. It’s easy to see why – the planet’s surface temperature averages more than 420 degrees Celsius and its dense atmosphere exerts a surface press more than 90 times experienced at sea level on Earth. Its clouds, meanwhile, are more than 80 per cent sulphuric acid. This inhospitable environment is partly why we haven’t been able to study Venus as well as we’d like. The planet has a nasty habit of melting and crushing any spacecraft that we send there.
But conditions in Venus’ atmosphere might not be so dreadful. The clouds about 31 kilometres above the rocky surface of the planet might reach temperatures of 30 degrees Celsius and have a pressure similar to that of Earth. We already know that microbes live in the atmosphere on Earth, so it’s plausible that life that once lived on the surface of Venus – back when it was a more hospitable place – could have made its way into the atmosphere and stayed there while conditions on the surface deteriorated.
Sorry about that. In scientific terms, this is a pretty promising signal though. On Earth phosphine is only made in the lab or by microorganisms and can be found in swamps as well as animal intestines. It’s present in large amounts on Jupiter and Saturn, but that’s because those planets have violent storms ideal for producing the gas and these conditions aren’t replicated anywhere else in the Solar System, as far as we know.
There are two other things that make the biological origin of phosphine a credible hypothesis. First, there’s quite a lot of it up there – about five to 20 parts per billion. That might sound tiny, but it’s thousands of times more than what you’d find in Earth’s atmosphere. Second, we know that phosphine is constantly being broken down by light so in order to detect it now it means that some process is constantly replenishing the phosphine in the atmosphere.
Does that mean it’s definitely being produced by life?
No – not by a long shot. What it does mean is that we don’t know any chemical or physical process that could be generating this gas on Venus, which leaves biological origins as a plausible answer. It could be all down to some chemical process that we just don’t understand yet.
Venus is a pretty niche choice for life. I thought Mars was where all the action is?
For decades, scientists have argued that Venus might be able to support life, but we haven’t tried very hard to check it out as attention has focused on Mars and the icy moons of Jupiter and Saturn. It’s easy to see why – the planet’s surface temperature averages more than 420 degrees Celsius and its dense atmosphere exerts a surface press more than 90 times experienced at sea level on Earth. Its clouds, meanwhile, are more than 80 per cent sulphuric acid. This inhospitable environment is partly why we haven’t been able to study Venus as well as we’d like. The planet has a nasty habit of melting and crushing any spacecraft that we send there.
But conditions in Venus’ atmosphere might not be so dreadful. The clouds about 31 kilometres above the rocky surface of the planet might reach temperatures of 30 degrees Celsius and have a pressure similar to that of Earth. We already know that microbes live in the atmosphere on Earth, so it’s plausible that life that once lived on the surface of Venus – back when it was a more hospitable place – could have made its way into the atmosphere and stayed there while conditions on the surface deteriorated.
How do we find out for sure what’s really going on up there?
The phosphine measurements were made using two telescopes, the James Clerk Maxwell Telescope in Hawaii and the Atacama Large Millimeter/submillimeter Array in Chile and the team behind the discovery are working to confirm these observations with even more detailed measurements. But what we really need is a sample from the atmosphere so we can take a proper look at what’s going on.
A private company called Rocket Lab has a mission to Venus planned for 2023. Nasa also has shortlisted two possible Venus probes that could eventually head to our rocky next door neighbour while this discovery is likely to prompt a flurry of new proposed journeys. Any mission is likely to take a long time to be planned and carried out though, so we’ve got a wait on our hands until we have the next piece of evidence.
Matt Reynolds is WIRED's science editor. He tweets from @mattsreynolds1
The phosphine measurements were made using two telescopes, the James Clerk Maxwell Telescope in Hawaii and the Atacama Large Millimeter/submillimeter Array in Chile and the team behind the discovery are working to confirm these observations with even more detailed measurements. But what we really need is a sample from the atmosphere so we can take a proper look at what’s going on.
A private company called Rocket Lab has a mission to Venus planned for 2023. Nasa also has shortlisted two possible Venus probes that could eventually head to our rocky next door neighbour while this discovery is likely to prompt a flurry of new proposed journeys. Any mission is likely to take a long time to be planned and carried out though, so we’ve got a wait on our hands until we have the next piece of evidence.
Matt Reynolds is WIRED's science editor. He tweets from @mattsreynolds1
Life on Venus? Astronomers discover evidence of microbial life
A new study reveals the presence of phosphine on Venus:
a molecule that could be an indicator of microbial life in the planet's clouds.
By Iain Todd
September 14, 2020
Astronomers have discovered a rare molecule in the clouds of Venus that could indicate the presence of microbial life.
Venus is a scorching planet surrounded by thick, poisonous clouds, and might seem like an unlikely place to discover life beyond Earth, but a new study has found a rare molecule known as phosphine in the planet’s clouds.
On Earth, this molecule is only made either industrially or by microbes that survive in oxygen-free environments.
Astronomers have considered the possibility of microbial life high in the clouds around Venus for decades. Such microbes could avoid the scorching temperatures below, but would still need to withstand high levels of acidity.
While there is still much analysis to carry out, the detection of phosphine molecules could be a sign that there is extra-terrestrial life on Venus.
The discovery was made by a team of astronomers led by Professor Jane Greaves of Cardiff University and is described in a new paper in Nature Astronomy.
An artist’s impression of Venus, inset showing a representation of phosphine molecules. Credit: ESO / M. Kornmesser / L. Calçada & NASA / JPL / Caltech
The astronomers used the James Clerk Maxwell Telescope (JCMT) in Hawaii to detect phosphine around Venus, then turned to the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile for follow-up observations.
In both cases they observed Venus at a wavelength of about 1 millimetre, enabling them to see beyond the visible spectrum detectable by the human eye.
While the results look promising for the search for life elsewhere in the Solar System, the team say there is still some information lacking, and the presence of life cannot yet be confirmed.
One team member, Dr William Bains of the Massachusetts Institute of Technology, has been looking into ways that phosphine can be produced naturally.
Examples include sunlight, minerals being blown upwards from the surface of Venus, volcanoes and lighting, but, say the team, none of these sources could produce enough to explain the amount detected in the study.
Left: the James Clerk Maxwell Telescope. Right: ALMA. Credit: A. Woodcraft (AdamW at en.wikipedia) / ESO/José Francisco Salgado (josefrancisco.org)
Contrary to that, in order to create the amount of phosphine observed, terrestrial organisms would only need to operate at around 10% of their maximum productivity, according to Dr Paul Rimmer of the University of Cambridge.
Microbes on Venus would be very different to similar microbes on Earth in order to survive in Venus’s extreme conditions.
Many alternative ways of producing phosphine can be ruled out by this new study, but the team say that confirmation of the presence of life on Venus is still a long way away.
An image of Venus, observed in the 365nm waveband by the Venus Ultraviolet Imager (UVI) on board the Akatsuki probe. The observations were made on 6 May 2016, when the spacecraft saw the whole planet illuminated. Credit: J. Greaves / Cardiff University
Looking for life beyond Earth
The study is the latest in the search for life beyond Earth, whether it be methane on Mars or plumes erupting from subsurface oceans of icy moons like Enceladus at Saturn and Europa at Jupiter.
On Venus, dark streaks where ultraviolet light is absorbed could be explained by colonies of microbes, for example. The Japanese Akatsuki spacecraft is currently mapping these streaks to gather more information.
NASA’s Discovery Program is currently considering a proposed mission to send an orbiter to study Venus’s atmosphere, named DAVINCI+. If selected, it could launch in 2026.
If there is indeed microbial life on Venus, scientists appear to be getting closer and closer to confirming it.
Streaks in the clouds of Venus, as seen by JAXA’s Akatsuki orbiter (left) and reconstructed by simulations with the AFES-Venus computer programme (right). Credit: JAXA
“This was an experiment made out of pure curiosity, really, taking advantage of JCMT’s powerful technology, and thinking about future instruments,” says Professor Greaves.
“I thought we’d just be able to rule out extreme scenarios, like the clouds being stuffed full of organisms. When we got the first hints of phosphine in Venus’ spectrum, it was a shock!
“In the end, we found that both observatories had seen the same thing: faint absorption at the right wavelength to be phosphine gas, where the molecules are backlit by the warmer clouds below.”
A view of Enceladus’s south pole, captured by the Cassini spacecraft, 21 November 2009. On the limb can be seen plumes of water vapour erupting from the subsurface ocean below the moon’s icy crust. Could Enceladus’s ocean host microbial life? Credit: NASA/JPL/Space Science Institute
MIT’s Dr Clara Sousa Silva has been considering the search for phosphine as a so-called ‘biosignature’ gas of non-oxygen-using life on exoplanets.
“Finding phosphine on Venus was an unexpected bonus!” she says.
“The discovery raises many questions, such as how any organisms could survive. On Earth, some microbes can cope with up to about 5% of acid in their environment, but the clouds of Venus are almost entirely made of acid.”
Professor Emma Bunce, President of the Royal Astronomical Society, said of the discovery:
“A key question in science is whether life exists beyond Earth, and the discovery by Professor Jane Greaves and her team is a key step forward in that quest.
“I’m particularly delighted to see UK scientists leading such an important breakthrough: something that makes a strong case for a return space mission to Venus.”
For more information, view the study by visiting the Nature website.
Iain Todd is BBC Sky at Night Magazine’s staff writer.
By Iain Todd
September 14, 2020
Astronomers have discovered a rare molecule in the clouds of Venus that could indicate the presence of microbial life.
Venus is a scorching planet surrounded by thick, poisonous clouds, and might seem like an unlikely place to discover life beyond Earth, but a new study has found a rare molecule known as phosphine in the planet’s clouds.
On Earth, this molecule is only made either industrially or by microbes that survive in oxygen-free environments.
Astronomers have considered the possibility of microbial life high in the clouds around Venus for decades. Such microbes could avoid the scorching temperatures below, but would still need to withstand high levels of acidity.
While there is still much analysis to carry out, the detection of phosphine molecules could be a sign that there is extra-terrestrial life on Venus.
The discovery was made by a team of astronomers led by Professor Jane Greaves of Cardiff University and is described in a new paper in Nature Astronomy.
An artist’s impression of Venus, inset showing a representation of phosphine molecules. Credit: ESO / M. Kornmesser / L. Calçada & NASA / JPL / Caltech
The astronomers used the James Clerk Maxwell Telescope (JCMT) in Hawaii to detect phosphine around Venus, then turned to the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile for follow-up observations.
In both cases they observed Venus at a wavelength of about 1 millimetre, enabling them to see beyond the visible spectrum detectable by the human eye.
While the results look promising for the search for life elsewhere in the Solar System, the team say there is still some information lacking, and the presence of life cannot yet be confirmed.
One team member, Dr William Bains of the Massachusetts Institute of Technology, has been looking into ways that phosphine can be produced naturally.
Examples include sunlight, minerals being blown upwards from the surface of Venus, volcanoes and lighting, but, say the team, none of these sources could produce enough to explain the amount detected in the study.
Left: the James Clerk Maxwell Telescope. Right: ALMA. Credit: A. Woodcraft (AdamW at en.wikipedia) / ESO/José Francisco Salgado (josefrancisco.org)
Contrary to that, in order to create the amount of phosphine observed, terrestrial organisms would only need to operate at around 10% of their maximum productivity, according to Dr Paul Rimmer of the University of Cambridge.
Microbes on Venus would be very different to similar microbes on Earth in order to survive in Venus’s extreme conditions.
Many alternative ways of producing phosphine can be ruled out by this new study, but the team say that confirmation of the presence of life on Venus is still a long way away.
An image of Venus, observed in the 365nm waveband by the Venus Ultraviolet Imager (UVI) on board the Akatsuki probe. The observations were made on 6 May 2016, when the spacecraft saw the whole planet illuminated. Credit: J. Greaves / Cardiff University
Looking for life beyond Earth
The study is the latest in the search for life beyond Earth, whether it be methane on Mars or plumes erupting from subsurface oceans of icy moons like Enceladus at Saturn and Europa at Jupiter.
On Venus, dark streaks where ultraviolet light is absorbed could be explained by colonies of microbes, for example. The Japanese Akatsuki spacecraft is currently mapping these streaks to gather more information.
NASA’s Discovery Program is currently considering a proposed mission to send an orbiter to study Venus’s atmosphere, named DAVINCI+. If selected, it could launch in 2026.
If there is indeed microbial life on Venus, scientists appear to be getting closer and closer to confirming it.
Streaks in the clouds of Venus, as seen by JAXA’s Akatsuki orbiter (left) and reconstructed by simulations with the AFES-Venus computer programme (right). Credit: JAXA
“This was an experiment made out of pure curiosity, really, taking advantage of JCMT’s powerful technology, and thinking about future instruments,” says Professor Greaves.
“I thought we’d just be able to rule out extreme scenarios, like the clouds being stuffed full of organisms. When we got the first hints of phosphine in Venus’ spectrum, it was a shock!
“In the end, we found that both observatories had seen the same thing: faint absorption at the right wavelength to be phosphine gas, where the molecules are backlit by the warmer clouds below.”
A view of Enceladus’s south pole, captured by the Cassini spacecraft, 21 November 2009. On the limb can be seen plumes of water vapour erupting from the subsurface ocean below the moon’s icy crust. Could Enceladus’s ocean host microbial life? Credit: NASA/JPL/Space Science Institute
MIT’s Dr Clara Sousa Silva has been considering the search for phosphine as a so-called ‘biosignature’ gas of non-oxygen-using life on exoplanets.
“Finding phosphine on Venus was an unexpected bonus!” she says.
“The discovery raises many questions, such as how any organisms could survive. On Earth, some microbes can cope with up to about 5% of acid in their environment, but the clouds of Venus are almost entirely made of acid.”
Professor Emma Bunce, President of the Royal Astronomical Society, said of the discovery:
“A key question in science is whether life exists beyond Earth, and the discovery by Professor Jane Greaves and her team is a key step forward in that quest.
“I’m particularly delighted to see UK scientists leading such an important breakthrough: something that makes a strong case for a return space mission to Venus.”
For more information, view the study by visiting the Nature website.
Iain Todd is BBC Sky at Night Magazine’s staff writer.
No comments:
Post a Comment