̽��ֱ�� of Cambridge - Cardiff ̽��ֱ��

Strongest hints yet of biological activity outside the solar system

sc604 — Thu, 17 Apr 2025 04:09:34 +0000

Astronomers have detected the most promising signs yet of a possible biosignature outside the solar system, although they remain cautious.

Origins of black holes revealed in their spin, study finds

sc604 — Tue, 07 Jan 2025 12:12:06 +0000

̽��ֱ��size and spin of black holes can reveal important information about how and where they formed, according to new research. ̽��ֱ��study tests the idea that many of the black holes observed by astronomers have merged multiple times within densely populated environments containing millions of stars.

̽��ֱ��team, involving researchers from the ̽��ֱ�� of Cambridge, examined the public catalogue of 69 gravitational wave events involving binary black holes detected by ̽��ֱ��Laser Interferometer Gravitational-Wave Observatory (LIGO) and Virgo Observatory for clues about these successive mergers, which they believe create black holes with distinctive spin patterns.

They discovered that a black hole’s spin changes when it reaches a certain mass, suggesting it may have been produced through a series of multiple previous mergers.

Their study, published in the journal Physical Review Letters, shows how spin measurements can reveal the formation history of a black hole and offers a step forward in understanding the diverse origins of these astrophysical phenomena.

“As we observe more black hole mergers with gravitational wave detectors like LIGO and Virgo, it becomes ever clearer that black holes exhibit diverse masses and spins, suggesting they may have formed in different ways,” said lead author Dr Fabio Antonini from Cardiff ̽��ֱ��. “However, identifying which of these formation scenarios is most common has been challenging.”

̽��ֱ��team pinpointed a clear mass threshold in the gravitational waves data where black hole spins consistently change.

They say this pattern aligns with existing models which assume black holes are produced through repeat collisions in clusters, rather than other environments where spin distributions are different.

This result supports a robust and relatively model-independent signature for identifying these kinds of black holes, something that has been challenging to confirm until now, according to the team.

“Our study gives us a powerful, data-driven way to identify the origins of a black hole’s formation history, showing that the way it spins is a strong indicator of it belonging to a group of high-mass black holes, which form in densely populated star clusters where small black holes repeatedly collide and merge with one another,” said co-author Dr Isobel Romero-Shaw, from Cambridge’s Department of Applied Mathematics and Theoretical Physics.

Their study will now help astrophysicists further refine computer models which simulate the formation of black holes, helping to shape how future gravitational wave detections are interpreted.

“Collaborating with other researchers and using advanced statistical methods will help to confirm and expand our findings, especially as we move toward next-generation detectors,” said co-author Dr Thomas Callister from the ̽��ֱ�� of Chicago. “ ̽��ֱ��Einstein Telescope, for example, could detect even more massive black holes and provide unprecedented insights into their origins.”

Reference:
Fabio Antonini, Isobel M Romero-Shaw, and Thomas Callister. 'Star Cluster Population of High Mass Black Hole Mergers in Gravitational Wave Data.' Physical Review Letters (2025). DOI: 10.1103/PhysRevLett.134.011401

Adapted from a Cardiff ̽��ֱ�� media release.

Gravitational waves data held clues for high-mass black holes’ violent beginnings.

NASA, ESA, and D Coe, J Anderson, and R van der Marel (STScI)

Computer-simulated image of a supermassive black hole at the core of a galaxy.

̽��ֱ��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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Earth’s earliest forest revealed in Somerset fossils

sc604 — Thu, 07 Mar 2024 10:27:02 +0000

̽��ֱ��oldest fossilised forest known on Earth – dating from 390 million years ago – has been found in the high sandstone cliffs along the Devon and Somerset coast of South West England.

‘Antisocial’ damselfish are scaring off cleaner fish customers – and this could contribute to coral reef breakdown

cg605 — Thu, 23 Feb 2023 09:00:35 +0000

̽��ֱ��meal of choice for the Caribbean cleaner fish, the sharknose goby, is a platter of parasites, dead tissue, scales and mucus picked off the bodies of other fishes. By removing these morsels, gobies are offering their ‘cleaning services’ to other marine life – a famous example of a mutually beneficial relationship between species.

But new research from the ̽��ֱ�� of Cambridge and Cardiff ̽��ֱ�� shows that when gobies inadvertently set up shop within the territories of aggressive damselfish, damselfish scare off the gobies’ ‘choosy client customers’.

̽��ֱ��study, published today in Behavioral Ecology, is an example of a largely unexplored phenomenon: a mutually beneficial relationship in nature being disrupted by a third party.

Sharknose gobies work solo or band together and set up a ‘cleaning station’: a fixed location in a particular nook of coral reef, where other marine life burdened by parasites go to take advantage of the gobies’ dietary needs.

“Gobies wait at cleaning stations for customers to visit, similar to shops. And with customers, come the parasites,” said Dr Katie Dunkley, a behavioural ecologist at the ̽��ֱ�� of Cambridge’s Department of Zoology. “In return for providing a cleaning service the gobies receive a payment of food.”

Customers are varied and include parrotfish, surgeonfish and butterflyfish. These choosy client fish shop around, visiting different cleaning stations open for business. If interested, they will adopt a stationary pose that makes a clean more likely – typically a head or tail-stand position with all fins flared.

During a clean – which could last from a few seconds to several minutes – gobies make physical contact with the customer, removing parasites and other dead body tissue. This is known as ‘tactile stimulation’ and, as well as getting rid of parasites, it may act as a massage reducing the customer’s stress, says Dunkley. Previous research has established the importance of cleaners – their removal led to fewer numbers and less variety of fish species on reefs.

“Cleaning stations act as a marketplace, and if customers stop showing up, over time a cleaning station is going to go out of business,” said Dunkley.

Five researchers spent over 34 hours observing cleaning stations on a shallow fringing reef in Tobago over a period of six weeks. Equipped with snorkels and waterproof paper they recorded underwater interactions for 10-minute periods from 8am-5:15pm each day.

They found that client fish were less likely to go to cleaning stations that were more often patrolled by damselfish, who scared ‘intruders’ away.

“I thought that damselfish might play a role as they visit cleaning stations too – although don’t often get cleaned – but to see just how influential they were was startling.

“Damselfish act like farmers as they weed out algae they don’t want, to encourage their preferred algae to grow. Damselfish are protective over their algal territories, and these antisocial fish spend a lot of time patrolling their territories, scaring away intruders through biting, attacking, chasing or threatening displays.”

Damselfish’s territories cover up to 70% of some reefs. On a healthy coral reef, a balance is maintained between algae and coral. But as reefs deteriorate and overfishing intensifies, algae thrive. As reefs deteriorate damselfish may become more common and/or aggressive – leading to fewer species receiving the goby cleaning treatment needed to keep them healthy, says Dunkley. This could ultimately contribute to the breakdown of delicate ecosystems supported by reefs.

“In future we’d like to tease out the motives of damselfish. Are they driven by wanting to protect their algae farms or monopolise cleaning stations?” said Dunkley, a Charles Darwin and Galapagos Islands Fund Junior Research Fellow at Christ’s College, Cambridge.

“Just as humans are connected through family, friends and colleagues, all fish are connected to each other. It’s important that we don’t just look at relationships in isolated bubbles. We need to step back and see how all fish are connected so that we can protect ecosystems like coral reefs.”

̽��ֱ��study was funded by a Natural Environment Research Council GW4+ studentship and Christ’s College ̽��ֱ�� of Cambridge Galapagos Islands Fund (both awarded to first author, Katie Dunkley). Last author, James Herbert-Read, was supported by the Whitten Lectureship in Marine Biology, and a Swedish Research Council Grant (2018–04076).

Dunkley et al, ̽��ֱ��presence of territorial damselfish predicts choosy client species richness at cleaning stations, Behavioral Ecology, DOI: doi.org/10.1093/beheco/arac122

Damselfish have been discovered to disrupt ‘cleaning services’ vital to the health of reefs. And climate change may mean this is only likely to get worse.

"We need to step back and see how all fish are connected so that we can protect ecosystems like coral reefs."

Dr Katie Dunkley

Secrets of the reef revealed

Federica Grassi / Moment via Getty Images

̽��ֱ��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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Hints of life discovered on Venus

sc604 — Mon, 14 Sep 2020 15:00:00 +0000

Astronomers have speculated for decades that high clouds on Venus could offer a home for microbes – floating free of the scorching surface, but tolerating very high acidity. ̽��ֱ��detection of phosphine molecules, which consist of hydrogen and phosphorus, is an important step in the search for life beyond Earth, a key question in science. ̽��ֱ��results are reported in the journal Nature Astronomy.

̽��ֱ��discovery was made by Professor Jane Greaves while she was a visitor at the ̽��ֱ�� of Cambridge’s Institute of Astronomy. Greaves and her collaborators used the James Clerk Maxwell Telescope (JCMT) in Hawaii to detect the phosphine, and followed up their discovery on the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile. Both facilities observe Venus at a wavelength of about 1 millimetre, much longer than the human eye can see.

“This was an experiment made out of pure curiosity, really – taking advantage of JCMT’s powerful technology, and thinking about future instruments,” said Greaves, who is based at Cardiff ̽��ֱ��. “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!”

Luckily, conditions were good at ALMA for follow-up observations while Venus was at a suitable angle to Earth. Processing the data was challenging, however, as ALMA isn’t usually looking for subtle effects in bright objects like Venus.

“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,” said Greaves.

Using existing models of the Venusian atmosphere to interpret the data, the researchers found that phosphine is present but scarce – only about twenty molecules in every billion. ̽��ֱ��astronomers then ran calculations to see if the phosphine could come from natural processes on Venus. They caution that some information is lacking – in fact, the only other study of phosphorus on Venus came from one lander experiment, carried by the Soviet Vega 2 mission in 1985.

On Earth, phosphine is only made industrially or by microbes that thrive in oxygen-free environments. Co-author Dr William Bains from MIT led the work on assessing natural ways to make phosphine on Venus. Ideas included sunlight, minerals blown upwards from the surface, volcanoes, or lightning, but none of these could make anywhere near enough. Natural sources were found to make at most one ten-thousandth of the amount of phosphine that the telescopes saw.

To create the observed quantity of phosphine on Venus, terrestrial organisms would only need to work at about 10% of their maximum productivity, according to calculations by co-author Dr Paul Rimmer of Cambridge’s Department of Earth Sciences. Any microbes on Venus will likely be very different from their Earth cousins though, to survive in hyper-acidic conditions.

“This discovery brings us right to the shores of the unknown,” said Rimmer, who is also affiliated with Cambridge's Cavendish Laboratory. “Phosphine is very hard to make in the oxygen-rich, hydrogen-poor clouds of Venus and fairly easy to destroy. ̽��ֱ��presence of life is the only known explanation for the amount of phosphine inferred by observations.

“Both of these facts lie at the edge of our knowledge: the observations could be caused by an unknown molecule, or could be caused by chemistry we’re not aware of. Ultimately, the only way to find out what's really happening is to send a mission into the clouds of Venus to take a sample of the droplets and look at them to see what's inside.”

Earth bacteria can absorb phosphate minerals, add hydrogen, and ultimately expel phosphine gas. It costs them energy to do this, so why they do it is not clear. ̽��ֱ��phosphine could be just a waste product, but other scientists have suggested purposes like warding off rival bacteria.

Co-author Dr Clara Sousa Silva from MIT was also thinking about searching for phosphine as a ‘biosignature’ gas of non-oxygen-using life on planets around other stars because normal chemistry makes so little of it. “Finding phosphine on Venus was an unexpected bonus,” she said. “ ̽��ֱ��discovery raises many questions, such as how any organisms could survive. On Earth, some microbes can cope with up to about 5% acid in their environment – but the clouds of Venus are almost entirely made of acid.”

Other possible biosignatures in the Solar System may exist, like methane on Mars and water venting from the icy moons Europa and Enceladus. On Venus, it has been suggested that dark streaks where ultraviolet light is absorbed could come from colonies of microbes. ̽��ֱ��Akatsuki spacecraft, launched by the Japanese space agency JAXA, is currently mapping these dark streaks to understand more about this unknown ultraviolet absorber.

̽��ֱ��team believes their discovery is significant because they can rule out many alternative ways to make phosphine, but they acknowledge that confirming the presence of ‘life’ needs a lot more work. Although the high clouds of Venus have temperatures up to a pleasant 30 degrees Celsius, they are incredibly acidic – around 90% sulphuric acid – posing major issues for microbes to survive there. ̽��ֱ��researchers are investigating the possibility that the microbes could shield themselves inside droplets.

̽��ֱ��team is now awaiting more telescope time to establish whether the phosphine is in a relatively temperate part of the clouds and to look for other gases associated with life. New space missions could also travel to our neighbouring planet, and sample the clouds to search for signs of life.

Professor Emma Bunce, President of the Royal Astronomical Society, said: “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.”

Reference:
Jane S. Greaves et al. ‘Phosphine Gas in the Cloud Decks of Venus.’ Nature Astronomy (2020). DOI: 10.1038/s41550-020-1174-4

Adapted from an RAS press release.

A UK-led team of astronomers has discovered a rare molecule – phosphine – in the clouds of Venus, pointing to the possibility of extra-terrestrial ‘aerial’ life.

̽��ֱ��presence of life is the only known explanation for the amount of phosphine inferred by observations

Paul Rimmer

JAXA / ISAS / Akatsuki Project Team

Synthesized false colour image of Venus

Yes

New type of supercomputer could be based on ‘magic dust’ combination of light and matter

sc604 — Mon, 25 Sep 2017 15:00:00 +0000

̽��ֱ��researchers, from Cambridge, Southampton and Cardiff Universities in the UK and the Skolkovo Institute of Science and Technology in Russia, have used quantum particles known as polaritons – which are half light and half matter – to act as a type of ‘beacon’ showing the way to the simplest solution to complex problems. This entirely new design could form the basis of a new type of computer that can solve problems that are currently unsolvable, in diverse fields such as biology, finance or space travel. ̽��ֱ��results are reported in the journal Nature Materials.

Our technological progress -- from modelling protein folding and behaviour of financial markets to devising new materials and sending fully automated missions into deep space -- depends on our ability to find the optimal solution of a mathematical formulation of a problem: the absolute minimum number of steps that it takes to solve that problem.

̽��ֱ��search for an optimal solution is analogous to looking for the lowest point in a mountainous terrain with many valleys, trenches, and drops. A hiker may go downhill and think that they have reached the lowest point of the entire landscape, but there may be a deeper drop just behind the next mountain. Such a search may seem daunting in natural terrain, but imagine its complexity in high-dimensional space. “This is exactly the problem to tackle when the objective function to minimise represents a real-life problem with many unknowns, parameters, and constraints,” said Professor Natalia Berloff of Cambridge’s Department of Applied Mathematics and Theoretical Physics and the Skolkovo Institute of Science and Technology, and the paper’s first author.

Modern supercomputers can only deal with a small subset of such problems when the dimension of the function to be minimised is small or when the underlying structure of the problem allows it to find the optimal solution quickly even for a function of large dimensionality. Even a hypothetical quantum computer, if realised, offers at best the quadratic speed-up for the “brute-force” search for the global minimum.

Berloff and her colleagues approached the problem from an unexpected angle: What if instead of moving along the mountainous terrain in search of the lowest point, one fills the landscape with a magical dust that only shines at the deepest level, becoming an easily detectible marker of the solution?

“A few years ago our purely theoretical proposal on how to do this was rejected by three scientific journals,” said Berloff. “One referee said, ‘Who would be crazy enough to try to implement this?!’ So we had to do it ourselves, and now we’ve proved our proposal with experimental data.”

Their ‘magic dust’ polaritons are created by shining a laser at stacked layers of selected atoms such as gallium, arsenic, indium, and aluminium. ̽��ֱ��electrons in these layers absorb and emit light of a specific colour. Polaritons are ten thousand times lighter than electrons and may achieve sufficient densities to form a new state of matter known as a Bose-Einstein condensate, where the quantum phases of polaritons synchronise and create a single macroscopic quantum object that can be detected through photoluminescence measurements.

̽��ֱ��next question the researchers had to address was how to create a potential landscape that corresponds to the function to be minimised and to force polaritons to condense at its lowest point. To do this, the group focused on a particular type of optimisation problem, but a type that is general enough so that any other hard problem can be related to it, namely minimisation of the XY model which is one of the most fundamental models of statistical mechanics. ̽��ֱ��authors have shown that they can create polaritons at vertices of an arbitrary graph: as polaritons condense, the quantum phases of polaritons arrange themselves in a configuration that correspond to the absolute minimum of the objective function.

“We are just at the beginning of exploring the potential of polariton graphs for solving complex problems,” said co-author Professor Pavlos Lagoudakis, Head of the Hybrid Photonics Lab at the ̽��ֱ�� of Southampton and the Skolkovo Institute of Science and Technology, where the experiments were performed. “We are currently scaling up our device to hundreds of nodes, while testing its fundamental computational power. ̽��ֱ��ultimate goal is a microchip quantum simulator operating at ambient conditions.”

Reference:
Natalia G. Berloff et al. ‘Realizing the classical XY Hamiltonian in polariton simulators.’ Nature Materials (2017). DOI: 10.1038/nmat4971

A team of researchers from the UK and Russia have successfully demonstrated that a type of ‘magic dust’ which combines light and matter can be used to solve complex problems and could eventually surpass the capabilities of even the most powerful supercomputers.

One referee said, ‘Who would be crazy enough to try to implement this?!’

Natalia Berloff

Kirill Kalinin

Creating polariton condensates in the vertices of an arbitrary graph and reading out the quantum phases that represent the absolute minimum of an XY Model

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

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New origami-like material may help prevent brain injuries in sport

sc604 — Wed, 23 Dec 2015 06:00:00 +0000

Researchers from Cambridge and Cardiff Universities are developing an origami-like material that could help prevent brain injuries in sport, as part of a programme sponsored in part by American football’s National Football League (NFL).

A number of universities and commercial companies are taking part in the NFL’s Head Health Challenge, which, as one of its goals, aims to develop the next generation of advanced materials for use in helmets and other types of body protection, for sport, military and other applications.

̽��ֱ��Cambridge and Cardiff team are working in collaboration with helmet designer and manufacturer Charles Owen Inc, with funding support from the NFL, GE Healthcare, Under Armour and the National Institute of Standards and Technology, to develop and test their material over the next 12 months.

̽��ֱ��Head Health Challenge competition is a $20 million collaborative project to develop new and innovative technologies in order to improve early-stage detection of mild traumatic brain injuries and to improve brain protection. ̽��ֱ��five-year collaboration is aiming to improve the safety of athletes, members of the military and society overall.

“ ̽��ֱ��key challenge for us is to come up with a material that can be optimised for a range of different types of impacts,” said Dr Graham McShane of Cambridge’s Department of Engineering, who is part of the team behind the material. “A direct impact is different than an oblique impact, so the ideal material will behave and deform accordingly, depending on how it’s been hit – what we are looking at is the relationship between the material, geometry and the force of impact.”

In high-impact sports such as American football, players can hit each other with the equivalent of half a ton of force, and in an average game, there can be dozens of these high-impact blocks or tackles. More than 100 concussions are reported each year in the NFL, and over the course of a career, multiple concussions can do serious long-term damage.

̽��ֱ��Head Health Challenge has created three separate challenges as part of its program of funding: Challenge I – Methods for Diagnosis and Prognosis of Mild Traumatic Brain Injuries; Challenge II – Innovative Approaches for Preventing and Identifying Brain Injuries; and Challenge III – Advanced Materials for Impact Mitigation. ̽��ֱ��C³ project is part of Challenge III. ̽��ֱ��various projects from Challenge III will have their efforts judged in a year’s time by a review panel, with the most promising technology receiving another $500,000 to develop the material further.

̽��ֱ��multi-layered, elastic material developed by McShane and his colleagues at Cambridge and Cardiff, called C³, has been designed and tested using a mixture of theoretical and experimental techniques, so that it can be tailored for specific impact scenarios.

C³ has its origins in cellular materials conceived in the Department of Engineering for defence applications, and is based on folded, origami-like structures. It is more versatile than the polymer foams currently used in protective helmets, which are highly limited in terms of how they behave under different conditions.

Structures made from C³ can be designed in such a way that impact energy can be dissipated relatively easily, making it an ideal material to use in protective clothing and accessories.

Dr Peter Theobald, a Senior Lecturer at Cardiff ̽��ֱ�� who is leading on the project, said: “Head injury prevention strategies have remained relatively stagnant versus the evolution of other technologies. Our trans-Atlantic collaboration with Charles Owen Inc. has enabled us to pool our highly relevant skills and expertise in injury prevention, mechanics, manufacturing and commercialisation.”

“This approach has already enabled us to develop C³which, in the words of our evaluators, presents a potentially ‘game-changing’ material with great promise to better absorb the vertical and horizontal components of an oblique impact. This highly prestigious award provides us with a platform to continue developing C³ towards our ultimate goal of achieving a material that provides a step-change in head health and protection, whilst achieving metrics that ensure commercial viability.”

Inset image: Sample of C³. Credit: Cardiff ̽��ֱ��.

Adapted from Cardiff ̽��ֱ�� press release.

Researchers are developing the next generation of advanced materials for use in sport and military applications, with the goal of preventing brain injuries.

̽��ֱ��key challenge for us is to come up with a material that can be optimised for a range of different types of impacts

Graham McShane

Elvis Kennedy

Eddie Lacy (cropped)

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

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