̽��ֱ�� of Cambridge - Harvard ̽��ֱ��

‘Altar tent’ discovery puts Islamic art at the heart of medieval Christianity

ta385 — Sat, 01 Feb 2025 06:00:00 +0000

A 13th-century fresco rediscovered in Ferrara provides unique evidence of medieval churches using Islamic tents to conceal their high altars. Dr Federica Gigante believes the 700-year-old fresco could be the only surviving image of its kind, offering precious evidence of a little-known Christian practice.

Scientists reveal structure of 74 exocomet belts orbiting nearby stars

Anonymous — Fri, 17 Jan 2025 08:00:00 +0000

̽��ֱ��crystal-clear images show light being emitted from these millimetre-sized pebbles within the belts that orbit 74 nearby stars of a wide variety of ages – from those that are just emerging to those in more mature systems like our own Solar System.

̽��ֱ��REASONS (REsolved ALMA and SMA Observations of Nearby Stars) study, led by Trinity College Dublin and involving researchers from the ̽��ֱ�� of Cambridge, is a milestone in the study of exocometary belts because its images and analyses reveal where the pebbles, and the exocomets, are located. They are typically tens to hundreds of astronomical units (the distance from Earth to the Sun) from their central star.

In these regions, it is so cold (-250 to -150 degrees Celsius) that most compounds are frozen as ice on the exocomets. What the researchers are therefore observing is where the ice reservoirs of planetary systems are located. REASONS is the first programme to unveil the structure of these belts for a large sample of 74 exoplanetary systems. ̽��ֱ��results are reported in the journal Astronomy & Astrophysics.

This study used both the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile and the Submillimeter Array (SMA) in Hawai‘i to produce the images that have provided more information on populations of exocomets than ever before. Both telescope arrays observe electromagnetic radiation at millimetre and submillimetre wavelengths.

“Exocomets are boulders of rock and ice, at least one kilometre in size, which smash together within these belts to produce the pebbles that we observe here with the ALMA and SMA arrays of telescopes,” said lead author Luca Matrà from Trinity College Dublin. “Exocometary belts are found in at least 20% of planetary systems, including our own Solar System.”

“ ̽��ֱ��images reveal a remarkable diversity in the structure of belts,” said co-author Dr Sebastián Marino from the ̽��ֱ�� of Exeter. “Some are narrow rings, as in the canonical picture of a ‘belt’ like our Solar System’s Edgeworth-Kuiper belt. But a larger number of them are wide, and probably better described as ‘disks’ rather than rings.”

Some systems have multiple rings/disks, some of which are eccentric, providing evidence that yet undetectable planets are present and their gravity affects the distribution of pebbles in these systems.

“ ̽��ֱ��power of a large study like REASONS is in revealing population-wide properties and trends,” said Matrà.

For example, the study confirmed that the number of pebbles decreases for older planetary systems as belts run out of larger exocomets smashing together, but showed for the first time that this decrease in pebbles is faster if the belt is closer to the central star. It also indirectly showed – through the belts’ vertical thickness – that objects as large as 140 km across and even Moon-size objects are likely present in these belts.

“We have been studying exocometary belts for decades, but until now only a handful had been imaged,” said co-author Professor Mark Wyatt from Cambridge’s Institute of Astronomy. “This is the largest collection of such images and demonstrates that we already have the capabilities to probe the structures of the planetary systems orbiting a large fraction of the stars near to the Sun.”

“Arrays like the ALMA and SMA used in this work are extraordinary tools that are continuing to give us incredible new insights into the universe and its workings,” said co-author Dr David Wilner from the Center for Astrophysics | Harvard & Smithsonian “ ̽��ֱ��REASONS survey required a large community effort and has an incredible legacy value, with multiple potential pathways for future investigation.”

Reference:
L. Matrà et al. ‘REsolved ALMA and SMA Observations of Nearby Stars. REASONS: A population of 74 resolved planetesimal belts at millimetre wavelengths.’ Astronomy & Astrophysics (2025). DOI: 10.1051/0004-6361/202451397

Adapted from a Trinity College Dublin media release.

An international team of astrophysicists has imaged a large number of exocomet belts around nearby stars, and the tiny pebbles within them.

Luca Matra, Trinity College Dublin, and colleagues

Millimetre continuum images for the REASONS resolved sample of 74 exocomet belts

̽��ֱ��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.

Yes

Facing ̽��ֱ��New Reality

plc32 — Tue, 05 Mar 2024 15:24:18 +0000

Climate action film "Facing ̽��ֱ��New Reality" featuring Cambridge Zero Director Professor Emily Shuckburgh is a finalist for the Smiley Charity Film Awards.

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

Yes

Emissions and evasions

plc32 — Wed, 20 Dec 2023 15:58:09 +0000

How Big Oil influences climate conversations on social media.

US gun violence: half of people from Chicago witness a shooting by age 40, study suggests

fpjl2 — Tue, 09 May 2023 15:07:11 +0000

A study tracking the lives of Chicagoans from childhood and adolescence in the 1990s to the start of middle age has found that 56% of Black and Hispanic residents from across the city witnessed at least one shooting by the time they turned 40.

White residents were exposed to gun violence at less than half the rate of Black and Hispanic residents, although it was still high: 25% of White Chicagoans had witnessed a shooting before turning forty.

Across racial categories, 50% of all the study’s participants had been exposed to gun violence by age 40. ̽��ֱ��average age to witness a shooting was just 14 years old.

Of those in the study, more than 7% of Black and Hispanic people had themselves been shot before turning forty, compared to 3% of White people. ̽��ֱ��average age for being shot was 17 years old.

Researchers also compared the locations of gun violence incidents* in the year leading up to recent study interviews in 2021. Rates of shootings within a 250-metre radius of the homes of Black participants were over 12 times higher than those of White participants. Rates of shootings near the homes of Hispanic people were almost four times higher than for White people.

̽��ֱ��research team continued to gather data for participants who had moved out of the city, although the vast majority of gun violence took place within Chicago.

̽��ֱ��sustained stress of living with the potential for gun violence likely takes a “cumulative physiological toll” on Chicago’s citizens – and people in cities across the US, argue researchers.

Findings from the latest study, led by a ̽��ֱ�� of Cambridge criminologist in collaboration with researchers from Harvard and Oxford universities, are published in JAMA Network Open, a journal of the American Medical Association

“Existing evidence suggests that the long-term stress of exposure to firearm violence can contribute to everything from lower test scores for schoolkids to diminished life expectancy through heart disease,” said study lead author Dr Charles Lanfear, from the ̽��ֱ�� of Cambridge’s Institute of Criminology.

“We expected levels of exposure to gun violence to be high, but not this high. Our findings are frankly startling and disturbing,” said Lanfear. “A substantial portion of Chicago’s population could be living with trauma as a result of witnessing shootings and homicides, often at a very young age.”

“It is clear that Black people in particular are often living in a very different social context, with far higher risks of seeing and becoming victims of gun violence in the streets near their homes lasting into middle age.”

̽��ֱ��Project on Human Development in Chicago Neighborhoods (PHDCN), a Harvard ̽��ֱ�� study, has followed thousands of children since they were first surveyed in the 1990s, gathering life experiences as they grow up in the city or move away. Participants are from households selected at random from a set list of eighty Chicago districts – carefully chosen to reflect Chicago’s spectrum of race and levels of social advantage, or lack thereof.

̽��ֱ��latest research focused on data gathered from 2,418 of participants born in the early 1980s through to the mid-1990s, equally split between men and women.**

̽��ֱ��oldest study participants, born in 1981, hit adolescence in the early-to-mid 1990s when lethal violence reached a peak in the US. “ ̽��ֱ��nineties saw a demographic bump collide with high poverty levels and rises in gang crime resulting in part from the crack epidemic,” said Lanfear.

“However, since 2016 we have seen another surge in gun violence. Rates of fatal shootings in Chicago are now higher than they ever were in the nineties.”

Men are far more likely to be involved in violent crime, and this is reflected in the risks of actually being shot by age 40, which are five times higher for men than women. However, there was a much smaller difference between the sexes for exposure to gun violence: 43% of women and 58% of men had seen someone shot.

“ ̽��ֱ��chronic stress effects on women from being so highly exposed to firearm violence may well be substantial in Chicago, and indeed in many US cities,” said Lanfear.

“ ̽��ֱ��study participants are taken from right across Chicago, and only a tiny fraction will be involved in any kind of crime. Given the levels of women and children witnessing gun violence in the city, the vast majority of this exposure will be as bystanders in public spaces, in streets or outside schools.”

“ ̽��ֱ��public health consequences of life in violent and traumatised neighbourhoods will be playing out not just in Chicago, but in many cities right across the United States,” Lanfear said.

Study following thousands of Chicagoans from across the city over a 25-year period found that 50% of the study participants had seen a shooting before middle age.

A substantial portion of Chicago’s population could be living with trauma as a result of witnessing shootings and homicides

Charles Lanfear

Getty images

Police line in Chicago, Illinois, USA

Notes

*Taken from the Gun Violence Archive, and not-for-profit organisation that collates data on gun violence drawn from sources including police departments, media and government agencies.
** Racial make-up of the study participants as follows: 890 Black respondents, 1146 Hispanic respondents, and 382 White respondents. ̽��ֱ��research looked at data from PHDCN study groups born in 1984, 1987 and 1996. ̽��ֱ��research team say they can safely estimate exposure to gun violence up to age 40 for the majority of the study participants. Even the younger group, now 27, are on track to compare with older cohorts, as most shootings are witnessed during youth.

̽��ֱ��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.

Yes

Humanity’s quest to discover the origins of life in the universe

sc604 — Wed, 08 Mar 2023 17:10:32 +0000

For thousands of years, humanity and science have contemplated the origins of life in the Universe. While today’s scientists are well-equipped with innovative technologies, humanity has a long way to go before we fully understand the fundamental aspects of what life is and how it forms.

“We are living in an extraordinary moment in history,” said Professor Didier Queloz, who directs the Leverhulme Centre for Life in the Universe at Cambridge and ETH Zurich’s Centre for Origin and Prevalence of Life. While still a doctoral student, Queloz was the first to discover an exoplanet – a planet orbiting a star other than our Sun. ̽��ֱ��discovery led to him being awarded the 2019 Nobel Prize in Physics.

In the three decades since Queloz’s discovery, scientists have discovered more than 5,000 exoplanets. Trillions more are predicted to exist within our Milky Way galaxy alone. Each exoplanet discovery raises more questions about how and why life emerged on Earth and whether it exists elsewhere in the universe.

Technological advancements, such as the James Webb Space Telescope and interplanetary missions to Mars, give scientists access to huge volumes of new observations and data. Sifting through all this information to understand the emergence of life in the universe will take a big, multidisciplinary network.

In collaboration with chemist and fellow Nobel Laureate Jack Szostak and astronomer Dimitar Sasselov, Queloz announced the formation of such a network at the American Association for the Advancement of Science (AAAS) meeting in Washington, DC. ̽��ֱ��Origins Federation brings together researchers studying the origins of life at Cambridge, ETH Zurich, Harvard ̽��ֱ��, and ̽��ֱ�� ̽��ֱ�� of Chicago.

Together, Federation scientists will explore the chemical and physical processes of living organisms and environmental conditions hospitable to supporting life on other planets. “ ̽��ֱ��Origins Federation builds upon a long-standing collegial relationship strengthened through a shared collaboration in a recently completed project with the Simons Foundation,” said Queloz.

These collaborations support the work of researchers like Dr Emily Mitchell from Cambridge's Department of Zoology. Mitchell is co-director of Cambridge’s Leverhulme Centre for Life in the Universe and an ecological time traveller. She uses field-based laser-scanning and statistical mathematical ecology on 580-million-year-old fossils of deep-sea organisms to determine the driving factors that influence the macro-evolutionary patterns of life on Earth.

Speaking at AAAS, Mitchell took participants back to four billion years ago when Earth’s early atmosphere - devoid of oxygen and steeped in methane – showed its first signs of microbial life. She spoke about how life survives in extreme environments and then evolves offering potential astrobiological insights into the origins of life elsewhere in the universe.

“As we begin to investigate other planets through the Mars missions, biosignatures could reveal whether or not the origin of life itself and its evolution on Earth is just a happy accident or part of the fundamental nature of the universe, with all its biological and ecological complexities,” said Mitchell.

̽��ֱ��founding centres of the Origins Federation are ̽��ֱ��Origins of Life Initiative (Harvard ̽��ֱ��), Centre for Origin and Prevalence of Life (ETH Zurich), the Center for the Origins of Life ( ̽��ֱ�� of Chicago), and the Leverhulme Centre for Life in the Universe ( ̽��ֱ�� of Cambridge).

̽��ֱ��Origins Federation will pursue scientific research topics of interest to its founding centres with a long-term perspective and common milestones. It will strive to establish a stable funding platform to create opportunities for creative and innovative ideas, and to enable young scientists to make a career in this new field. ̽��ֱ��Origins Federation is open to new members, both centres and individuals, and is committed to developing the mechanisms and structure to achieve that aim.

“ ̽��ֱ��pioneering work of Professor Queloz has allowed astronomers and physicists to make advances that were unthinkable only a few years ago, both in the discovery of planets which could host life and the development of techniques to study them,” said Professor Andy Parker, head of Cambridge's Cavendish Laboratory. “But now we need to bring the full range of our scientific understanding to bear in order to understand what life really is and whether it exists on these newly discovered planets. ̽��ֱ��Cavendish Laboratory is proud to host the Leverhulme Centre for Life in the Universe and to partner with the Origins Federation to lead this quest.”

Scientists from the ̽��ֱ�� of Cambridge, ETH Zurich, Harvard ̽��ֱ��, and the ̽��ֱ�� of Chicago have founded the Origins Federation, which will advance our understanding of the emergence and early evolution of life, and its place in the cosmos.

ETH Zurich/NASA

L-R: Emily Mitchell, Didier Queloz, Kate Adamal, Carl Zimmer

̽��ֱ��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.

Yes

Researchers devise a new path toward ‘quantum light’

sc604 — Thu, 02 Feb 2023 16:00:00 +0000

̽��ֱ��researchers, from the ̽��ֱ�� of Cambridge, along with colleagues from the US, Israel and Austria, developed a theory describing a new state of light, which has controllable quantum properties over a broad range of frequencies, up as high as X-ray frequencies. Their results are reported in the journal Nature Physics.

̽��ֱ��world we observe around us can be described according to the laws of classical physics, but once we observe things at an atomic scale, the strange world of quantum physics takes over. Imagine a basketball: observing it with the naked eye, the basketball behaves according to the laws of classical physics. But the atoms that make up the basketball behave according to quantum physics instead.

“Light is no exception: from sunlight to radio waves, it can mostly be described using classical physics,” said lead author Dr Andrea Pizzi, who carried out the research while based at Cambridge’s Cavendish Laboratory. “But at the micro and nanoscale so-called quantum fluctuations start playing a role and classical physics cannot account for them.”

Pizzi, who is currently based at Harvard ̽��ֱ��, worked with Ido Kaminer’s group at the Technion-Israel Institute of Technology and colleagues at MIT and the ̽��ֱ�� of Vienna to develop a theory that predicts a new way of controlling the quantum nature of light.

“Quantum fluctuations make quantum light harder to study, but also more interesting: if correctly engineered, quantum fluctuations can be a resource,” said Pizzi. “Controlling the state of quantum light could enable new techniques in microscopy and quantum computation.”

One of the main techniques for generating light uses strong lasers. When a strong enough laser is pointed at a collection of emitters, it can rip some electrons away from the emitters and energise them. Eventually, some of these electrons recombine with the emitters they were extracted from, and the excess energy they absorbed is released as light. This process turns the low-frequency input light into high-frequency output radiation.

“ ̽��ֱ��assumption has been that all these emitters are independent from one another, resulting in output light in which quantum fluctuations are pretty featureless,” said Pizzi. “We wanted to study a system where the emitters are not independent, but correlated: the state of one particle tells you something about the state of another. In this case, the output light starts behaving very differently, and its quantum fluctuations become highly structured, and potentially more useful.”

To solve this type of problem, known as a many body problem, the researchers used a combination of theoretical analysis and computer simulations, where the output light from a group of correlated emitters could be described using quantum physics.

̽��ֱ��theory, whose development was led by Pizzi and Alexey Gorlach from the Technion, demonstrates that controllable quantum light can be generated by correlated emitters with a strong laser. ̽��ֱ��method generates high-energy output light, and could be used to engineer the quantum-optical structure of X-rays.

“We worked for months to get the equations cleaner and cleaner until we got to the point where we could describe the connection between the output light and the input correlations with just one compact equation. As a physicist, I find this beautiful,” said Pizzi. “Looking forward, we would like to collaborate with experimentalists to provide a validation of our predictions. On the theory side of things, our work suggests many-body systems as a resource for generating quantum light, a concept that we want to investigate more broadly, beyond the setup considered in this work.”

̽��ֱ��research was supported in part by the Royal Society. Andrea Pizzi is a Junior Research Fellow at Trinity College, Cambridge.

Reference:
Andrea Pizzi et al. ‘Light emission from strongly driven many-body systems.’ Nature Physics (2023). DOI: 10.1038/s41567-022-01910-7

Researchers have theorised a new mechanism to generate high-energy ‘quantum light’, which could be used to investigate new properties of matter at the atomic scale.

David Wall via Getty Images

Design of a glowing fractal pattern with stars floating on a black background

Yes