School of Physics and Astronomy

The data gathered provides unprecedented insights into the structure and composition of the Milky Way.

The VISTA (Visible and Infrared Survey Telescope for Astronomy), a European Southern Observatory (ESO) facility in Chile, has successfully mapped over 1.5 billion objects in the Milky Way.

Over the course of 13 years, the VISTA Variables in the Vía Láctea (VVV) survey and its extension, the VVV eXtended survey (VVVX), observed the central regions of the Milky Way. Beginning in 2010, these surveys required 420 nights of observation to capture approximately 200,000 images, monitoring over 1.5 billion celestial objects and generating 500 terabytes of scientific data. This represents the largest volume of data ever collected for an ESO observational project.

Notable discoveries

The data gathered provides unprecedented insights into the structure and composition of the Milky Way, the galaxy that contains our own Solar System. Notable discoveries include:

• Globular clusters: the oldest objects in our Galaxy.
• Hypervelocity stars: stars expelled from the Galaxy by the central supermassive black hole.
• Galactic windows: clear views through interstellar dust and gas to the other side of the Galaxy.
• RR Lyrae variable stars: the oldest known population in the centre of the Galaxy.
• Brown dwarf stars and binary floating planets: unique celestial objects that enhance our understanding of stellar and planetary formation.

UK role on VISTA

The University of Edinburgh is one of 18 UK universities which form part of the VISTA Consortium who work closely together with scientists from the Science and Technology Facilities Council through its team at the UK Astronomy Technology Centre (UK ATC) to play a role in the development and delivery of the telescope to the ESO.

Edinburgh involvement

The Wide-Field Astronomy Unit (WFAU) in the University of Edinburgh’s Institute for Astronomy curates and publishes the VVV/VVVX data, along with that from the other public surveys conducted with the VISTA telescope, in its VISTA Science Archive (VSA).

The WFAU Director, Prof Bob Mann said:

Members of the WFAU team – led by Dr Nick Cross – have been working closely with the VVV/VVVX consortium since their survey started. The VSA provides a long-term home for their survey data and many additional data products derived by the consortium, ensuring that their vast, and wonderfully rich, dataset will remain accessible to astronomers. Sky survey data has a scientific longevity, and researchers will be extracting exciting science from the VVV/VVVX dataset for many years to come.

Research could have implications on the emulsification and stability of new materials.

Physicists and mathematicians have turned their attention to a fascinating observation that has intrigued scientists and cocktail enthusiasts alike: the mysterious way ouzo, the anise-flavoured liquor, turns cloudy when water is added.

The research, which involved experts from the University of Edinburgh, Loughborough University and Nottingham Trent University, has resulted in a new mathematical model that offers insights into the spontaneous formation of microscopic droplets and how they can remain suspended in a liquid for a long time.

Revealing the maths taking place in the glass could have far-reaching implications, such as the creation of new materials, especially in fields such as pharmaceuticals, cosmetics, and food products, where the stability and distribution of microscopic particles are critical.

When water is added to ouzo, microscopic droplets form which are a result of the anise oil separating from the alcohol-water mixture. This causes the drink to turn cloudy as the droplets scatter light. The emulsification - the suspension of well-mixed oil droplets in the liquid - is something that requires a lot of energy in other systems and foods, but in the case of ouzo, it happens spontaneously. What’s also surprising is how long these droplets, and the resulting cloudiness, remain stable in the mixture without separating, especially when compared to other food emulsions.

By mixing alcohol, oil, and water in varying proportions, the researchers were able to observe phase separation and measure key properties like surface tension.

They used this data and a statistical mechanical modelling method known as ‘classical density functional theory’ to develop their mathematical model.

This model has been used to calculate a phase diagram that details the stable combinations of the ouzo ingredients.

Detector explores weaker dark matter interactions than ever searched for before.

Exploring weakly interacting massive particles

Figuring out the nature of dark matter, the invisible substance that makes up most of the mass in our universe, is one of the greatest puzzles in physics. New results from the world’s most sensitive dark matter detector, LUX-ZEPLIN (LZ), have narrowed down possibilities for one of the leading dark matter candidates: weakly interacting massive particles, or WIMPs.

LZ hunts for dark matter from a cavern nearly one mile underground at the Sanford Underground Research Facility in South Dakota. The experiment’s new results explore weaker dark matter interactions than ever searched before and further limit what WIMPs could be.

The scientists involved in this latest work have noted that the detector and analysis techniques are performing even better than expected.

LZ uses 10 tonnes of liquid xenon to provide a dense, transparent material for dark matter particles to potentially bump into. The hope is for a WIMP to knock into a xenon nucleus, causing it to move, much like a hit from a cue ball in a game of pool. By collecting the light and electrons emitted during interactions, LZ captures potential WIMP signals alongside other data.

What is dark matter?

Dark matter, so named because it does not emit, reflect, or absorb light, is estimated to make up 85% of the mass in the universe but has never been directly detected, though it has left its fingerprints on multiple astronomical observations. We wouldn’t exist without this mysterious yet fundamental piece of the universe; dark matter’s mass contributes to the gravitational attraction that helps galaxies form and stay together.

International collaboration

LZ is a collaboration of roughly 250 scientists from 38 institutions in the United States, United Kingdom, Portugal, Switzerland, South Korea, and Australia; much of the work building, operating, and analysing the record-setting experiment is done by early career researchers.

At the School of Physics and Astronomy, Professor Alex Murphy and Dr Sally Shaw lead a group of researchers contributing to many aspects of LZ, including neutron backgrounds and searches for other dark matter candidates such as axions.  Sally served as LZ’s Physics Coordinator from 2022 to earlier this year, overseeing most of the data-taking and leading a substantial part of the analysis for the new results.

Dr Sally Shaw said:

This result was only possible due to many excellent physicists working very hard together, despite spanning most of the world's time zones! Doing science on this scale is a team game, and the LZ team has done a brilliant job once again delivering world-leading dark matter constraints.

The collaboration is already looking forward to analysing the next data set and using new analysis tricks to look for even lower-mass dark matter.

Congratulations to Dr Cyrielle Opitom who has been appointed a member of the RSE Young Academy of Scotland.

The Royal Society of Edinburgh (RSE) Young Academy of Scotland (YAS) scheme brings together young professionals from all areas of academia, business, third sector organisations and public life, to work together to address the most challenging issues facing society in Scotland and beyond.

Forty eight new members have just been appointed, who will join YAS’s existing members in realising its mission to achieve transformative societal change through citizenship, innovation, collaboration, evidence, and leadership.

Dr Cyrielle Opitom is a Chancellor’s Fellow, based in the School’s Institute for Astronomy. Dr Opitom’s research and expertise focuses on studying small bodies of the solar system and in particular comets. She uses and helps to develop the latest astronomical instrumentation to investigate the composition of comets and to understand what they can teach us about the history of the solar system. Cyrielle is also involved in projects aiming at developing astronomy in Africa.

Festival goers at the World of Music, Arts and Dance (WOMAD) were treated to a feast for the mind last weekend as Edinburgh physicists Professor Victoria Martin and Dr Alex Hall gave talks at the World of Physics pavilion.

WOMAD festival started in 1980 as the brainchild of musician Peter Gabriel, and takes place near Malmesbury, Wiltshire. The annual festival showcases musicians and performers from around the globe, and since 2016 has also hosted a range of physics events including talks, workshops, demonstrations, and panel discussions.

Professor Martin from the Institute for Particle and Nuclear Physics gave a talk celebrating the life and work of the late Professor Peter Higgs. She commented:

It was a great honour to be at WOMAD to talk about Peter Higgs and his legacy to physics and to our world.  I'm sure Peter would have very much appreciated the spirit of the festival of bringing people together to celebrate the arts, science and culture from all over the globe.

Dr Alex Hall from the Institute for Astronomy gave a talk on the Euclid space telescope, showcasing its incredible imaging power and explaining the fundamental physics of dark matter and dark energy that the mission aims to shed light upon.

Dr Hall said:

It was a privilege to be invited to speak at WOMAD. Having science events alongside literature, art, and music exposes people to different ideas and perspectives that they may not usually encounter and is one of the reasons this festival is so special.

Both talks were given to a capacity crowd of several hundred and were very well received by the engaged and captivated audience.

The talks were sponsored by CERN & Society Foundation.

Students on the MSc degree in Astrobiology and Planetary Sciences have been sharing their knowledge and understanding about life on other planets with a video games company.

Auroch Digital, an independent game development company based in Bristol, is creating the video game ‘Mars Horizon 2: The Search for Life’, whose players will run a space agency, investigate the solar system and collect evidence of life.

The collaboration, which also involved astrobiology staff, included a number of online meetings and a visit from game developers to the University. Students carried out research and made scientific suggestions to inform in-game scenarios.

A  tour of lab facilities conducted during the visit involved a demonstration of chemical reactions, the viewing of samples including rocks, minerals, organisms and fossils, and a guide to the ‘Mars chamber’, which reproduces the pressure, temperature and atmospheric composition of Mars to see how various materials and processes behave under those conditions.

Students on the interdisciplinary MSc degree in Astrobiology and Planetary Sciences work to understand the nature of life and whether we might find it elsewhere in the universe. They build on their knowledge of  physics, chemistry, biology and geosciences to answer fundamental questions about living matter, how it forms, varies and evolves in concert with planets and stars, and how it is distributed across time and space.

An estimated 3.2 billion people worldwide play video games, making this one of the most popular forms of entertainment. With the steady rise in popularity of gaming over the past few years, there may be further opportunities for collaboration with scientists.

Madeleine Landell, a student on the MSc Astrobiology and Planetary Sciences degree commented:

Collaborating with Auroch on Mars Horizon 2 has been an incredible opportunity. It has both given us astrobiology students a glimpse into the creative and meticulously researched process that goes into videogame development, as well as allowing us to think differently about advances in space science. The Auroch team's dedication to preserving as much real science as possible in the video game was really impressive. They weren't afraid to get into the semantics of molecular biology and geochemistry in their pursuit of a scientifically accurate yet exciting game. We've left this collaboration with renewed excitement about how our current astrobiological research could contribute to the future of space exploration. We really look forward to the release of Mars Horizon 2.

John O’Donnell, Lead Game Designer on Mars Horizon 2 said:

We had so much fun collaborating with the students of the MSc programme. It was a privilege to see and hear about their work and have their influence on the game’s vision and authenticity. The students helped us research many what-if scenarios of life in our solar system and because of their diverse backgrounds this took the game in interesting new directions.

The School of Physics and Astronomy is delighted to welcome Professor Philip Best to the position of Head of School

Professor Best was previously the Head of the Institute for Astronomy within the School of Physics and Astronomy, a post which he undertook for 4 years. 

Professor Best plans to continue building on the successes made within the School during the past few years. Additional priorities include strengthening research impact collaborations, supporting the development of teaching and student support initiatives, fostering a diverse and inclusive environment, and enhancing community engagement.

Professor Best takes over from Professor Dunlop who will devote his Royal Society Research Professorship to work in the area of galaxy formation and evolution.
 

Congratulations to Dr Stewart Gault who has received a Royal Society of Edinburgh grant to support his research in understanding how bacteria survives at low temperatures.

The Small Research Grant from the Royal Society of Edinburgh (RSE) covers the costs arising from a defined research project and encourages high-quality research and academic innovation.

The limits of life

One of the major goals in astrobiology is discerning the limits to life and how life has adapted to extreme environments, thereby informing us as to whether extreme environments found beyond Earth are potentially capable of supporting life.

Understanding the habitability of subzero temperature environments is particularly important as the icy moons Europa and Enceladus contain vast quantities of liquid water. However, we do not know what the low temperature limit for life is, or whether it is set by one factor or a combination of factors.

Record holder

The current record holder for low temperature growth and metabolism is Planococcus halocryophilus (P. halocryophilus), which can replicate at -15°C, while maintaining metabolic activity down to -25°C. The mechanisms which facilitate this low temperature activity are currently unknown.

Research project

This RSE Grant will enable Dr Gault to investigate whether it is the onset of intracellular vitrification that enforces a limit for P. halocryophilus’ low temperature activity and whether P. halocryophilus has adaptations which can modulate its intracellular vitrification.

In addition, he will be exploring whether the presence of extracellular ions found in the natural environment and the growth medium confer any depression of P. halocryophilus’ intracellular vitrification, thereby permitting low temperature metabolic activity without the need for specific vitrification oriented adaptions.

Congratulations to Dr Beckmann who has received a UK Research and Innovation (UKRI) Future Leaders Fellowship (FLF).

Supermassive black holes

Dr Beckmann’s research focuses on supermassive black holes, which are some of the most extreme objects in the Universe. Today, every massive galaxy has a supermassive black hole in its centre. With each black hole weighing more than a small galaxy, such massive objects cannot form directly. Instead, today's supermassive black holes started out as small black holes when the Universe was young, over 12 billion years ago.

Her fellowship success will enable her to use powerful simulations to tackle the difficult challenge of how black holes in the early Universe move in and around galaxies. Dr Beckmann’s work will unveil when and how they first find their way into the galaxies where we can see them today, and quantify what impact they had on the early Universe. As part of this work she will take advantage of the recent wealth of insight from the James Webb Space telescope, and prepare for upcoming flagship missions such as the gravitational wave observatory LISA and the X-ray observatory NewATHENA.

Dr Beckmann originally joined the School of Physics and Astronomy in 2024 as an Elizabeth Gardner fellow. 

UK Research and Innovation Future Leaders Fellowship

The UKRI FLF scheme supports universities, businesses, and other research and innovation environments to develop their most talented people into a next wave of world-class leaders.

The scheme provides long-term support in order to enable fellows to tackle ambitious programmes, multidisciplinary questions, and new or emerging research and innovation areas and partnerships.

In this latest round, 68 fellows will be funded a total of £104 million to lead research into global issues and commercialise their innovations in the UK.

Astronomers have created the most detailed weather report so far for two distant worlds beyond our own solar system.

The international study – the first of its kind – reveals the extreme atmospheric conditions on the celestial objects, which are swathed in swirling clouds of hot sand amid temperatures of 950C.

Using NASA’s powerful James Webb Space Telescope (JWST), researchers set out to capture the weather on a pair of brown dwarfs – cosmic bodies that are bigger than planets but smaller than stars. These brown dwarfs, named collectively as WISE 1049AB, are the brightest and closest objects of their type to Earth, around six light years away.

The team tracked each brown dwarf’s atmosphere by measuring the light waves emitted from their surfaces, which change as more or less cloudy regions revolve in and out of view. By visualising this data through light curves – a plot of how the brightness of light from each object changes over time – the team was able to build up a detailed 3D picture of how the brown dwarfs’ weather changed over the course of a full rotation or day, between five and seven hours. The team was also able to plot how the light from each object varied by wavelength, to demonstrate the presence and complex interplay of gases such as water, methane, and carbon monoxide in their atmospheres. The insights may help astronomers develop the understanding of brown dwarfs as a potential missing link between stars and planets – promising new insights into both.

By observing the infrared part of the light spectrum, the JWST is able to observe wavelengths of light that are blocked by our own atmosphere. This capability opens frontiers in the study of the early universe, star formation, and so-called exoplanets such as brown dwarfs which lie beyond our solar system.

The latest study builds on previous studies of brown dwarfs, which have mainly been confined to capturing static snapshots of their atmosphere on only one side. This approach is limited, as brown dwarfs are known to rotate relatively quickly and their weather can vary greatly over time, researchers say. 

Their findings will pave the way for more detailed studies into brown dwarfs and other distant celestial objects.

The study, published in Monthly Notices of the Royal Astronomical Society, was led by the University of Edinburgh in collaboration with researchers from Trinity College Dublin, the University of Virginia, and other institutes from around the world.

Professor Beth Biller said

Our findings show that we are on the cusp of transforming our understanding of worlds far beyond our own.  Insights such as these can help us understand the conditions not just on celestial objects like brown dwarfs, but also on giant exoplanets beyond our solar system.  Eventually, the techniques we are refining here may enable the first detections of weather on habitable planets like our own, which orbit other stars.