̽��ֱ�� of Cambridge - planets

Researchers deal a blow to theory that Venus once had liquid water on its surface

sc604 — Mon, 02 Dec 2024 16:01:07 +0000

̽��ֱ��researchers, from the ̽��ֱ�� of Cambridge, studied the chemical composition of the Venusian atmosphere and inferred that its interior is too dry today for there ever to have been enough water for oceans to exist at its surface. Instead, the planet has likely been a scorching, inhospitable world for its entire history.

̽��ֱ��results, reported in the journal Nature Astronomy, have implications for understanding Earth’s uniqueness, and for the search for life on planets outside our Solar System. While many exoplanets are Venus-like, the study suggests that astronomers should narrow their focus to exoplanets which are more like Earth.

From a distance, Venus and Earth look like siblings: it is almost identical in size and is a rocky planet like Earth. But up close, Venus is more like an evil twin: it is covered with thick clouds of sulfuric acid, and its surface has a mean temperature close to 500°C.

Despite these extreme conditions, for decades, astronomers have been investigating whether Venus once had liquid oceans capable of supporting life, or whether some mysterious form of ‘aerial’ life exists in its thick clouds now.

“We won’t know for sure whether Venus can or did support life until we send probes at the end of this decade,” said first author Tereza Constantinou, a PhD student at Cambridge’s Institute of Astronomy. “But given it likely never had oceans, it is hard to imagine Venus ever having supported Earth-like life, which requires liquid water.”

When searching for life elsewhere in our galaxy, astronomers focus on planets orbiting their host stars in the habitable zone, where temperatures are such that liquid water can exist on the planet’s surface. Venus provides a powerful limit on where this habitable zone lies around a star.

“Even though it’s the closest planet to us, Venus is important for exoplanet science, because it gives us a unique opportunity to explore a planet that evolved very differently to ours, right at the edge of the habitable zone,” said Constantinou.

There are two primary theories on how conditions on Venus may have evolved since its formation 4.6 billion years ago. ̽��ֱ��first is that conditions on the surface of Venus were once temperate enough to support liquid water, but a runaway greenhouse effect caused by widespread volcanic activity caused the planet to get hotter and hotter. ̽��ֱ��second theory is that Venus was born hot, and liquid water has never been able to condense at the surface.

“Both of those theories are based on climate models, but we wanted to take a different approach based on observations of Venus’ current atmospheric chemistry,” said Constantinou. “To keep the Venusian atmosphere stable, then any chemicals being removed from the atmosphere should also be getting restored to it, since the planet’s interior and exterior are in constant chemical communication with one another.”

̽��ֱ��researchers calculated the present destruction rate of water, carbon dioxide and carbonyl sulphide molecules in Venus’ atmosphere, which must be restored by volcanic gases to keep the atmosphere stable.

Volcanism, through its supply of gases to the atmosphere, provides a window into the interior of rocky planets like Venus. As magma rises from the mantle to the surface, it releases gases from the deeper portions of the planet.

On Earth, volcanic eruptions are mostly steam, due to our planet’s water-rich interior. But, based on the composition of the volcanic gases necessary to sustain the Venusian atmosphere, the researchers found that volcanic gases on Venus are at most six percent water. These dry eruptions suggest that Venus’s interior, the source of the magma that releases volcanic gases, is also dehydrated.

At the end of this decade, NASA’s DAVINCI mission will be able to test and confirm whether Venus has always been a dry, inhospitable planet, with a series of flybys and a probe sent to the surface. ̽��ֱ��results could help astronomers narrow their focus when searching for planets that can support life in orbit around other stars in the galaxy.

“If Venus was habitable in the past, it would mean other planets we have already found might also be habitable,” said Constantinou. “Instruments like the James Webb Space Telescope are best at studying the atmospheres of planets close to their host star, like Venus. But if Venus was never habitable, then it makes Venus-like planets elsewhere less likely candidates for habitable conditions or life.

“We would have loved to find that Venus was once a planet much closer to our own, so it’s kind of sad in a way to find out that it wasn’t, but ultimately it’s more useful to focus the search on planets that are mostly likely to be able to support life – at least life as we know it.”

̽��ֱ��research was supported in part by the Science and Technology Facilities Council (STFC), part of UK Research and Innovation (UKRI).

Reference:
Tereza Constantinou, Oliver Shorttle, and Paul B Rimmer. ‘A dry Venusian interior constrained by atmospheric chemistry.’ Nature Astronomy (2024). DOI: 10.1038/s41550-024-02414-5

A team of astronomers has found that Venus has never been habitable, despite decades of speculation that our closest planetary neighbour was once much more like Earth than it is today.

NASA/Jet Propulsion Laboratory-Caltech

View of surface of Venus

̽��ֱ��text in this work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

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Neon sign identified by JWST gives clue to planet formation

Anonymous — Tue, 05 Mar 2024 15:06:11 +0000

Planetary systems like our Solar System seem to contain more rocky objects than gas-rich ones. Around our sun, these include the inner planets, the asteroid belt and the Kuiper belt. But scientists have known for a long time that planet-forming discs start with 100 times more mass in gas than in solids, which leads to a pressing question; when and how does most of the gas leave the disc/system?

JWST is helping scientists uncover how planets form, by advancing understanding of their birthplaces, the circumstellar discs surrounding young stars. In a new study published in the Astronomical Journal, a team of scientists including those from the ̽��ֱ�� of Leicester, the ̽��ֱ�� of Cambridge and led by the ̽��ֱ�� of Arizona, image for the first time an old planet-forming disc (still very young relative to the Sun) which is actively dispersing its gas content.

Knowing when the gas disperses is important as it constrains the time that is left for nascent planets to consume the gas from their surroundings.

During the very early stages of planetary system formation, planets coalesce in a spinning disc of gas and tiny dust around the young star. These particles clump together, building up into bigger and bigger chunks called planetesimals. Over time, these planetesimals collide and stick together, eventually forming planets. ̽��ֱ��type, size, and location of planets that form depend on the amount of material available and how long it remains in the disc. So, the outcome of planet formation depends on the evolution and dispersal of the disc.

At the heart of this discovery is the observation of T Cha, a young star (relative to the Sun) enveloped by an eroding disc notable for its vast dust gap, approximately 30 astronomical units in radius. For the first time, astronomers have imaged the dispersing gas (aka winds) using the four lines of the noble gases neon (Ne) and argon (Ar), one of which is the first detection in a planet-forming disc. ̽��ֱ��images of [Ne II] show that the wind is coming from an extended region of the disc. ̽��ֱ��team is also interested in knowing how this process takes place, so they can better understand the history and impact on our solar system.

Scientists have been trying to understand the mechanisms behind the winds in protoplanetary discs for over a decade. ̽��ֱ��observations by JWST represent a huge step-change in the data they have to work with, compared to previous data from ground-based telescopes.

“We first used neon to study planet-forming discs more than a decade ago, testing our computational simulations against data from Spitzer, and new observations we obtained with the ESO VLT,” said co-author Professor Richard Alexander from the ̽��ֱ�� of Leicester. “We learned a lot, but those observations didn’t allow us to measure how much mass the discs were losing.

“ ̽��ֱ��new JWST data are spectacular, and being able to resolve disc winds in images is something I never thought would be possible. With more observations like this still to come, JWST will enable us to understand young planetary systems as never before.”

“These winds could be driven either by high-energy stellar photons (the star's light) or by the magnetic field that weaves the planet-forming disc,” said Naman Bajaj from the ̽��ֱ�� of Arizona, the study’s lead author.

To differentiate between the two, the same group, this time led by Dr Andrew Sellek of Leiden Observatory and previously of the Institute of Astronomy at the ̽��ֱ�� of Cambridge, performed simulations of the dispersal driven by stellar photons. They compare these simulations to the actual observations and find dispersal by high-energy stellar photons can explain the observations, and hence cannot be excluded as a possibility.

“ ̽��ֱ��simultaneous measurement of all four lines by JWST proved crucial to pinning down the properties of the wind and helped us to demonstrate that significant amounts of gas are being dispersed,” said Sellek.

To put it into context, the researchers calculate that the mass dispersing every year is equivalent to that of the moon! These results will be published in a companion paper, currently under review at the Astronomical Journal.

̽��ֱ��[Ne II] line was discovered towards several planet-forming discs in 2007 with the Spitzer Space Telescope and soon identified as a tracer of winds by team member Professor Ilaria Pascucci at the ̽��ֱ�� of Arizona; this transformed research efforts focused on understanding disc gas dispersal. Now the discovery of spatially resolved [Ne II] - as well as the first detection of [Ar III] - using the James Webb Space Telescope, could become the next step towards transforming our understanding of this process.

̽��ֱ��implications of these findings offer new insights into the complex interactions that lead to the dispersal of the gas and dust critical for planet formation. By understanding the mechanisms behind disc dispersal, scientists can better predict the timelines and environments conducive to the birth of planets. ̽��ֱ��team's work demonstrates the power of JWST and sets a new path for exploring planet formation dynamics and the evolution of circumstellar discs.

Reference:
Naman S Bajaj et al. ‘JWST MIRI MRS Observations of T Cha: Discovery of a Spatially Resolved Disk Wind.’ ̽��ֱ��Astronomical Journal (2024). DOI: 10.3849/1538-3881/ad22e1

Adapted from a ̽��ֱ�� of Leicester press release.

̽��ֱ��winds that help to form planets in the gaseous discs of early solar systems have been imaged for the first time by the James Webb Space Telescope (JWST) using the noble gases neon and argon.

ESO/M. Kornmesser

Artist's impression of the surroundings of the supermassive black hole in NGC 3783

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Mysterious missing component in the clouds of Venus revealed

vb425 — Tue, 09 Jan 2024 10:05:24 +0000

What are the clouds of Venus made of? Scientists know they are mainly made of sulfuric acid droplets, with some water, chlorine, and iron. Their concentrations vary with height in the thick and hostile Venusian atmosphere. But until now they have been unable to identify the missing component that would explain the clouds’ patches and streaks, only visible in the UV range.

In a study published in Science Advances, researchers from the ̽��ֱ�� of Cambridge synthesised iron-bearing sulfate minerals that are stable under the harsh chemical conditions in the Venusian clouds. Spectroscopic analysis revealed that a combination of two minerals, rhomboclase and acid ferric sulfate, can explain the mysterious UV absorption feature on our neighbouring planet.

“ ̽��ֱ��only available data for the composition of the clouds were collected by probes and revealed strange properties of the clouds that so far we have been unable to fully explain,” said Paul Rimmer from the Cavendish Laboratory and co-author of the study. “In particular, when examined under UV light, the Venusian clouds featured a specific UV absorption pattern. What elements, compounds, or minerals are responsible for such observation?”

Formulated on the basis of Venusian atmospheric chemistry, the team synthesised several iron-bearing sulfate minerals in an aqueous geochemistry laboratory in the Department of Earth Sciences. By suspending the synthesised materials in varying concentrations of sulfuric acid and monitor the chemical and mineralogical changes, the team narrowed down the candidate minerals to rhomboclase and acid ferric sulfate, of which the spectroscopic features were examined under light sources specifically designed to mimic the spectrum of solar flares (Rimmer’s FlareLab; Cavendish Laboratory).

Researchers from Harvard ̽��ֱ�� provided measurements of the UV absorbance patterns of ferric iron under extreme acidic conditions, in an attempt to mimic the even more extreme Venusian clouds. ̽��ֱ��scientists are part of the newly-established Origins Federation, which promotes such collaborative projects.

“ ̽��ֱ��patterns and level of absorption shown by the combination of these two mineral phases are consistent with the dark UV-patches observed in Venusian clouds,” said co-author Clancy Zhijian Jiang, from the Department of Earth Sciences, Cambridge. “These targeted experiments revealed the intricate chemical network within the atmosphere, and shed light on the elemental cycling on the Venusian surface.”

“Venus is our nearest neighbour, but it remains a mystery,” said Rimmer. “We will have a chance to learn much more about this planet in the coming years with future NASA and ESA missions set to explore its atmosphere, clouds and surface. This study prepares the grounds for these future explorations.”

̽��ֱ��research was supported by the Simons Foundation, and the Origins Federation.

Reference:
Clancy Zhijian Jiang et al., ‘Iron-sulfur chemistry can explain the ultraviolet absorber in the clouds of Venus.’ Science Advances (2024). DOI:10.1126/sciadv.adg8826

Researchers may have identified the missing component in the chemistry of the Venusian clouds that would explain their colour and 'splotchiness' in the UV range, solving a longstanding mystery.

FreelanceImages/Universal Images Group/Science Photo Library via Getty Images

Sunrise over Venus

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‘Bouncing’ comets could deliver building blocks for life to exoplanets

sc604 — Wed, 15 Nov 2023 00:10:19 +0000

In order to deliver organic material, comets need to be travelling relatively slowly – at speeds below 15 kilometres per second. At higher speeds, the essential molecules would not survive – the speed and temperature of impact would cause them to break apart.

̽��ֱ��most likely place where comets can travel at the right speed are ‘peas in a pod’ systems, where a group of planets orbit closely together. In such a system, the comet could essentially be passed or ‘bounced’ from the orbit of one planet to another, slowing it down.

At slow enough speeds, the comet would crash on a planet’s surface, delivering the intact molecules that researchers believe are the precursors for life. ̽��ֱ��results, reported in the Proceedings of the Royal Society A, suggest that such systems would be promising places to search for life outside our Solar System if cometary delivery is important for the origins of life.

Comets are known to contain a range of the building blocks for life, known as prebiotic molecules. For example, samples from the Ryugu asteroid, analysed in 2022, showed that it carried intact amino acids and vitamin B3. Comets also contain large amounts of hydrogen cyanide (HCN), another important prebiotic molecule. ̽��ֱ��strong carbon-nitrogen bonds of HCN make it more durable to high temperatures, meaning it could potentially survive atmospheric entry and remain intact.

“We’re learning more about the atmospheres of exoplanets all the time, so we wanted to see if there are planets where complex molecules could also be delivered by comets,” said first author Richard Anslow from Cambridge’s Institute of Astronomy. “It’s possible that the molecules that led to life on Earth came from comets, so the same could be true for planets elsewhere in the galaxy.”

̽��ֱ��researchers do not claim that comets are necessary to the origin of life on Earth or any other planet, but instead they wanted to place some limits on the types of planets where complex molecules, such as HCN, could be successfully delivered by comets.

Most of the comets in our Solar System sit beyond the orbit of Neptune, in what is known as the Kuiper Belt. When comets or other Kuiper Belt objects (KBOs) collide, they can be pushed by Neptune’s gravity toward the Sun, eventually getting pulled in by Jupiter’s gravity. Some of these comets make their way past the Asteroid Belt and into the inner Solar System.

“We wanted to test our theories on planets that are similar to our own, as Earth is currently our only example of a planet that supports life,” said Anslow. “What kinds of comets, travelling at what kinds of speed, could deliver intact prebiotic molecules?”

Using a variety of mathematical modelling techniques, the researchers determined that it is possible for comets to deliver the precursor molecules for life, but only in certain scenarios. For planets orbiting a star similar to our own Sun, the planet needs to be low mass and it is helpful for the planet to be in close orbit to other planets in the system. ̽��ֱ��researchers found that nearby planets on close orbits are much more important for planets around lower-mass stars, where the typical speeds are much higher.

In such a system, a comet could be pulled in by the gravitational pull of one planet, then passed to another planet before impact. If this ‘comet-passing’ happened enough times, the comet would slow down enough so that some prebiotic molecules could survive atmospheric entry.

“In these tightly-packed systems, each planet has a chance to interact with and trap a comet,” said Anslow. “It’s possible that this mechanism could be how prebiotic molecules end up on planets.”

For planets in orbit around lower-mass stars, such as M-dwarfs, it would be more difficult for complex molecules to be delivered by comets, especially if the planets are loosely packed. Rocky planets in these systems also suffer significantly more high-velocity impacts, potentially posing unique challenges for life on these planets.

̽��ֱ��researchers say their results could be useful when determining where to look for life outside the Solar System.

“It’s exciting that we can start identifying the type of systems we can use to test different origin scenarios,” said Anslow. “It’s a different way to look at the great work that’s already been done on Earth. What molecular pathways led to the enormous variety of life we see around us? Are there other planets where the same pathways exist? It’s an exciting time, being able to combine advances in astronomy and chemistry to study some of the most fundamental questions of all.”

̽��ֱ��research was supported in part by the Royal Society and the Science and Technology Facilities Council (STFC), part of UK Research and Innovation (UKRI). Richard Anslow is a Member of Wolfson College, Cambridge.

Reference:
R J Anslow, A Bonsor and P B Rimmer. ‘Can comets deliver prebiotic molecules to rocky exoplanets?’ Proceedings of the Royal Society A (2023). DOI: 10.1098/rspa.2023.0434

How did the molecular building blocks for life end up on Earth? One long-standing theory is that they could have been delivered by comets. Now, researchers from the ̽��ֱ�� of Cambridge have shown how comets could deposit similar building blocks to other planets in the galaxy.

It’s possible that the molecules that led to life on Earth came from comets, so the same could be true for planets elsewhere in the galaxy

Richard Anslow

solarseven via Getty Images

Artist's impression of a meteor hitting Earth

̽��ֱ��text in this work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – as here, on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

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Carbon-based molecules found in atmosphere of exoplanet K2-18b

sc604 — Mon, 11 Sep 2023 11:39:20 +0000

An international team of astronomers led by the ̽��ֱ�� of Cambridge has used data from the NASA/ESA/CSA James Webb Space Telescope to discover methane and carbon dioxide in the atmosphere of K2-18 b, an exoplanet in the ‘Goldilocks zone’. This is the first time that carbon-based molecules have been discovered in the atmosphere of an exoplanet in the habitable zone.

Scottish rocks to play a key role in Mars space mission

sc604 — Fri, 28 Jul 2023 15:48:18 +0000

A group of scientists, including from the ̽��ֱ�� of Cambridge, have this week been collecting samples of rock from the NatureScot National Nature Reserve (NNR) as part of the NASA and European Space Agency (ESA)’s Mars Sample Return Program.

̽��ֱ��programme is gathering samples of rocks from around the world that bear a similarity to those on Mars, ahead of rock samples from the Red Planet being brought back to Earth in 2033.

Rum has been selected as the only UK site for sampling, and is a high priority in the programme, as some of its igneous rocks have a very similar mineral and chemical content to those that have been collected by NASA’s Perseverance Rover during its exploration of an ancient lakebed on Mars.

Intensive study of the rocks from Rum and around the globe will crucially help scientists understand what methods of testing and analysis will work best in readiness for when the Martian rocks return to Earth.

As the first samples from another world, the Mars rocks are thought to present the best opportunity to reveal clues about the early evolution of the planet, including the potential for past life.

̽��ֱ��Rum sampling is being led by Dr Lydia Hallis, a geologist and planetary scientist from the ̽��ֱ�� of Glasgow, and member of the programme’s Science Group. ̽��ֱ��team also includes scientists from the ̽��ֱ�� of Cambridge, the ̽��ֱ�� of Leicester and Brock ̽��ֱ�� in Canada.

“These Rum rocks are an excellent comparison to one particular Martian rock sample, which the NASA Perseverance Rover collected from the igneous Séítah Formation within Jezero crater,” said Hallis. “Not only is the mineralogy and chemistry similar, but the two rocks appear to have a similar amount of weathering.

“This seems strange when we think how wet and warm Rum is compared to present-day Mars, but billions of years ago when the Séítah formation crystallised on Mars the difference in environment would not have been so pronounced. At this time Mars was much wetter and warmer, with a thicker atmosphere that may even have produced rain (though not as much as we get in Scotland!). Over time the Martian atmosphere thinned, leaving the surface much dryer and colder, essentially halting any further weathering within Séítah and preserving the rocks at Jezero Crater for us to investigate today.

“ ̽��ֱ��rocks on Rum are much younger, but their exposure to the Scottish elements has produced roughly the same amount of weathering as was produced in the Séítah Formation during Mars’ early wet and warm climate. Because of all these similarities, analysis of the Rum rocks should give us a good head start and help the samples from the Red Planet achieve their full potential when they are returned to Earth.”

“It’s amazing to think that somewhere right here in the UK might be able to tell us something about the geology of a different planet,” said team member Professor Helen Williams from Cambridge’s Department of Earth Sciences. “We’ve still got several years left to wait before we can study the real Mars rocks, but in the meantime, our Scottish samples will provide scientists with the perfect material to test and refine the analytical techniques they will be using to investigate material returned from the Red Planet.”

Lesley Watt, NatureScot’s Rum NNR reserve manager, said: “With its extinct volcanoes and dramatic mountains, Rum has always been one of the best places to discover Scotland's world-class geology, but we didn’t quite realise that the rocks here were of interplanetary significance as well.

“It has been fascinating to learn more about the NASA/ESA mission, and really exciting for the island to play a small part in this truly historic endeavour to find out more about Mars. We hope it will add yet another element of interest for visitors to this special place.”

Adapted from a NatureScot press release.

Ancient rocks from the Isle of Rum in northwest Scotland are playing an important role in an international space mission to discover more about Mars.

It’s amazing to think that somewhere right here in the UK might be able to tell us something about the geology of a different planet

Helen Williams

NASA/JPL-Caltech

Illustration of NASA's Perseverance rover operating on the surface of Mars.

̽��ֱ��text in this work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – as here, on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

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Liquid water beneath Martian polar ice cap

sc604 — Thu, 29 Sep 2022 14:38:08 +0000

An international team of researchers has revealed new evidence for the possible existence of liquid water beneath the south polar ice cap of Mars.

No signs (yet) of life on Venus

sc604 — Tue, 14 Jun 2022 15:00:00 +0000

Researchers from the ̽��ֱ�� of Cambridge used a combination of biochemistry and atmospheric chemistry to test the ‘life in the clouds’ hypothesis, which astronomers have speculated about for decades, and found that life cannot explain the composition of the Venusian atmosphere.

Any life form in sufficient abundance is expected to leave chemical fingerprints on a planet’s atmosphere as it consumes food and expels waste. However, the Cambridge researchers found no evidence of these fingerprints on Venus.

Even if Venus is devoid of life, the researchers say their results, reported in the journal Nature Communications, could be useful for studying the atmospheres of similar planets throughout the galaxy, and the eventual detection of life outside our Solar System.

“We’ve spent the past two years trying to explain the weird sulphur chemistry we see in the clouds of Venus,” said co-author Dr Paul Rimmer from Cambridge’s Department of Earth Sciences. “Life is pretty good at weird chemistry, so we’ve been studying whether there’s a way to make life a potential explanation for what we see.”

̽��ֱ��researchers used a combination of atmospheric and biochemical models to study the chemical reactions that are expected to occur, given the known sources of chemical energy in Venus’s atmosphere.

“We looked at the sulphur-based ‘food’ available in the Venusian atmosphere – it’s not anything you or I would want to eat, but it is the main available energy source,” said Sean Jordan from Cambridge’s Institute of Astronomy, the paper’s first author. “If that food is being consumed by life, we should see evidence of that through specific chemicals being lost and gained in the atmosphere.”

̽��ֱ��models looked at a particular feature of the Venusian atmosphere – the abundance of sulphur dioxide (SO2). On Earth, most SO2 in the atmosphere comes from volcanic emissions. On Venus, there are high levels of SO2 lower in the clouds, but it somehow gets ‘sucked out’ of the atmosphere at higher altitudes.

“If life is present, it must be affecting the atmospheric chemistry,” said co-author Dr Oliver Shorttle from Cambridge’s Department of Earth Sciences and Institute of Astronomy. “Could life be the reason that SO2 levels on Venus get reduced so much?”

̽��ֱ��models, developed by Jordan, include a list of metabolic reactions that the life forms would carry out in order to get their ‘food’, and the waste by-products. ̽��ֱ��researchers ran the model to see if the reduction in SO2 levels could be explained by these metabolic reactions.

They found that the metabolic reactions can result in a drop in SO2 levels, but only by producing other molecules in very large amounts that aren’t seen. ̽��ֱ��results set a hard limit on how much life could exist on Venus without blowing apart our understanding of how chemical reactions work in planetary atmospheres.

“If life was responsible for the SO2 levels we see on Venus, it would also break everything we know about Venus’s atmospheric chemistry,” said Jordan. “We wanted life to be a potential explanation, but when we ran the models, it isn’t a viable solution. But if life isn’t responsible for what we see on Venus, it’s still a problem to be solved – there’s lots of strange chemistry to follow up on.”

Although there’s no evidence of sulphur-eating life hiding in the clouds of Venus, the researchers say their method of analysing atmospheric signatures will be valuable when JWST, the successor to the Hubble Telescope, begins returning images of other planetary systems later this year. Some of the sulphur molecules in the current study are easy to see with JWST, so learning more about the chemical behaviour of our next-door neighbour could help scientists figure out similar planets across the galaxy.

“To understand why some planets are alive, we need to understand why other planets are dead,” said Shorttle. “If life somehow managed to sneak into the Venusian clouds, it would totally change how we search for chemical signs of life on other planets.”

“Even if ‘our’ Venus is dead, it’s possible that Venus-like planets in other systems could host life,” said Rimmer, who is also affiliated with Cambridge’s Cavendish Laboratory. “We can take what we’ve learned here and apply it to exoplanetary systems – this is just the beginning.”

̽��ֱ��research was funded by the Simons Foundation and the Science and Technology Facilities Council (STFC), part of UK Research and Innovation (UKRI).

Reference:
Sean Jordan, Oliver Shorttle and Paul B Rimmer. ‘Proposed energy-metabolisms cannot explain the atmospheric chemistry of Venus.’ Nature Communications (2022). DOI: 10.1038/s41467-022-30804-8

̽��ֱ��unusual behaviour of sulphur in Venus’ atmosphere cannot be explained by an ‘aerial’ form of extra-terrestrial life, according to a new study.

Even if ‘our’ Venus is dead, it’s possible that Venus-like planets in other systems could host life

Paul Rimmer

NASA/JPL-Caltech

Venus from Mariner 10

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – as here, on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

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