From family archive to stage: The remarkable journey of ‘Not for a cat’ play at the Cambridge Festival
A recently rediscovered play, Not for a Cat: A Play for the Nuclear Age, will be premiering at the Cambridge Festival. The play was originally written in the 1950s by Wallace R. Harper, a student at the Cavendish Laboratory at the University of Cambridge in the 1920.
Webb Telescope sees galaxy in mysteriously clearing fog of early Universe
A key goal of the NASA/ESA/CSA James Webb Space Telescope has been to see further than ever before into the distant past of our Universe, when the first galaxies were forming after the Big Bang, a period know as cosmic dawn.
Researchers studying one of those very early galaxies have now made a discovery in the spectrum of its light, that challenges our established understanding of the Universe’s early history. Their results are reported in the journal Nature.
Webb discovered the incredibly distant galaxy JADES-GS-z13-1, observed at just 330 million years after the Big Bang. Researchers used the galaxy’s brightness in different infrared filters to estimate its redshift, which measures a galaxy’s distance from Earth based on how its light has been stretched out during its journey through expanding space.
The NIRCam imaging yielded an initial redshift estimate of 12.9. To confirm its extreme redshift, an international team led by Dr Joris Witstok, previously of the University of Cambridge’s Kavli Institute for Cosmology, observed the galaxy using Webb’s Near-Infrared Spectrograph (NIRSpec) instrument.
The resulting spectrum confirmed the redshift to be 13.0. This equates to a galaxy seen just 330 million years after the Big Bang, a small fraction of the Universe’s present age of 13.8 billion years.
But an unexpected feature also stood out: one specific, distinctly bright wavelength of light, identified as the Lyman-α emission radiated by hydrogen atoms. This emission was far stronger than astronomers thought possible at this early stage in the Universe’s development.
“The early Universe was bathed in a thick fog of neutral hydrogen,” said co-author Professor Roberto Maiolino from Cambridge’s Kavli Institute for Cosmology. “Most of this haze was lifted in a process called reionisation, which was completed about one billion years after the Big Bang.
“GS-z13-1 is seen when the Universe was only 330 million years old, yet it shows a surprisingly clear, telltale signature of Lyman-α emission that can only be seen once the surrounding fog has fully lifted. This result was totally unexpected by theories of early galaxy formation and has caught astronomers by surprise.”
Before and during the epoch of reionisation, neutral hydrogen fog surrounding galaxies blocked any energetic ultraviolet light they emitted, much like the filtering effect of coloured glass. Until enough stars had formed and were able to ionise the hydrogen gas, no such light — including Lyman-α emission — could escape from these fledgling galaxies to reach Earth.
The confirmation of Lyman-α radiation from this galaxy has great implications for our understanding of the early Universe. “We really shouldn’t have found a galaxy like this, given our understanding of the way the Universe has evolved,” said co-author Kevin Hainline from the University of Arizona. “We could think of the early Universe as shrouded with a thick fog that would make it exceedingly difficult to find even powerful lighthouses peeking through, yet here we see the beam of light from this galaxy piercing the veil.”
The source of the Lyman-α radiation from this galaxy is not yet known, but it may include the first light from the earliest generation of stars to form in the Universe. “The large bubble of ionised hydrogen surrounding this galaxy might have been created by a peculiar population of stars — much more massive, hotter and more luminous than stars formed at later epochs, and possibly representative of the first generation of stars,” said Witstok, who is now based at the Cosmic Dawn Center at the University of Copenhagen. A powerful active galactic nucleus, driven by one of the first supermassive black holes, is another possibility identified by the team.
The team plans further follow-up observations of GS-z13-1, aiming to obtain more information about the nature of this galaxy and origin of its strong Lyman-α radiation. Whatever the galaxy is concealing, it is certain to illuminate a new frontier in cosmology.
JWST is an international partnership between NASA, ESA and the Canadian Space Agency (CSA). The data for this result were captured as part of the JWST Advanced Deep Extragalactic Survey (JADES).
Reference:
Joris Witstok et al. ‘Witnessing the onset of reionization through Lyman-α emission at redshift 13.’ Nature (2025). DOI: 10.1038/s41586-025-08779-5
Adapted from an ESA media release.
Astronomers have identified a bright hydrogen emission from a galaxy in the very early Universe. The surprise finding is challenging researchers to explain how this light could have pierced the thick fog of neutral hydrogen that filled space at that time.
This result was totally unexpected by theories of early galaxy formation and has caught astronomers by surpriseRoberto MaiolinoESA/Webb, NASA, STScI, CSA, JADES CollaborationJADES-GS-z13-1 in the GOODS-S field
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Spinning, twisted light could power next-generation electronics
The researchers, led by the University of Cambridge and the Eindhoven University of Technology, have created an organic semiconductor that forces electrons to move in a spiral pattern, which could improve the efficiency of OLED displays in television and smartphone screens, or power next-generation computing technologies such as spintronics and quantum computing.
The semiconductor they developed emits circularly polarised light—meaning the light carries information about the ‘handedness’ of electrons. The internal structure of most inorganic semiconductors, like silicon, is symmetrical, meaning electrons move through them without any preferred direction.
However, in nature, molecules often have a chiral (left- or right-handed) structure: like human hands, chiral molecules are mirror images of one another. Chirality plays an important role in biological processes like DNA formation, but it is a difficult phenomenon to harness and control in electronics.
But by using molecular design tricks inspired by nature, the researchers created a chiral semiconductor by nudging stacks of semiconducting molecules to form ordered right-handed or left-handed spiral columns. Their results are reported in the journal Science.
One promising application for chiral semiconductors is in display technology. Current displays often waste a significant amount of energy due to the way screens filter light. The chiral semiconductor developed by the researchers naturally emits light in a way that could reduce these losses, making screens brighter and more energy-efficient.
“When I started working with organic semiconductors, many people doubted their potential, but now they dominate display technology,” said Professor Sir Richard Friend from Cambridge’s Cavendish Laboratory, who co-led the research. “Unlike rigid inorganic semiconductors, molecular materials offer incredible flexibility—allowing us to design entirely new structures, like chiral LEDs. It’s like working with a Lego set with every kind of shape you can imagine, rather than just rectangular bricks.”
The semiconductor is based on a material called triazatruxene (TAT) that self-assembles into a helical stack, allowing electrons to spiral along its structure, like the thread of a screw.
“When excited by blue or ultraviolet light, self-assembled TAT emits bright green light with strong circular polarisation—an effect that has been difficult to achieve in semiconductors until now,” said co-first author Marco Preuss, from the Eindhoven University of Technology. “The structure of TAT allows electrons to move efficiently while affecting how light is emitted.”
By modifying OLED fabrication techniques, the researchers successfully incorporated TAT into working circularly polarised OLEDs (CP-OLEDs). These devices showed record-breaking efficiency, brightness, and polarisation levels, making them the best of their kind.
“We’ve essentially reworked the standard recipe for making OLEDs like we have in our smartphones, allowing us to trap a chiral structure within a stable, non-crystallising matrix,” said co-first author Rituparno Chowdhury, from Cambridge’s Cavendish Laboratory. “This provides a practical way to create circularly polarised LEDs, something that has long eluded the field.”
The work is part of a decades-long collaboration between Friend’s research group and the group of Professor Bert Meijer from the Eindhoven University of Technology. “This is a real breakthrough in making a chiral semiconductor,” said Meijer. “By carefully designing the molecular structure, we’ve coupled the chirality of the structure to the motion of the electrons and that’s never been done at this level before.”
The chiral semiconductors represent a step forward in the world of organic semiconductors, which now support an industry worth over $60 billion. Beyond displays, this development also has implications for quantum computing and spintronics—a field of research that uses the spin, or inherent angular momentum, of electrons to store and process information, potentially leading to faster and more secure computing systems.
The research was supported in part by the European Union’s Marie Curie Training Network and the European Research Council. Richard Friend is a Fellow of St John’s College, Cambridge. Rituparno Chowdhury is a member of Fitzwilliam College, Cambridge.
Reference:
Rituparno Chowdhury, Marco D. Preuss et al. ‘Circularly polarized electroluminescence from chiral supramolecular semiconductor thin films.’ Science (2025). DOI:10.1126/science.adt3011
Researchers have advanced a decades-old challenge in the field of organic semiconductors, opening new possibilities for the future of electronics.
It’s like working with a Lego set with every kind of shape you can imagine, rather than just rectangular bricksRichard FriendSamarpita Sen, Rituparno ChowdhuryConfocal microscopy image of a chiral semiconductor
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Tributes paid to first British-Pakistani Head of House
Professor Ahmed, the first British-Pakistani Head of House, had a distinguished academic career centred on research interests in the physics and technology of nanoscale electronic devices, nanotechnology and electron beam lithography. Master of Corpus Christi College from 2000 to 2006, he remained actively involved as a Life Fellow and later an Honorary Fellow.
Born in Calcutta in 1936, after the partition of India Professor Ahmed and his family were forced to flee to Karachi in the newly formed Pakistan. The family later moved to London where Professor Ahmed read Electrical Engineering at Imperial College, graduating with a First Class degree. After a brief spell working for General Electric Company in Birmingham, he realised his passion was for research. Encouraged by a friend, he successfully applied for a PhD scholarship at King’s College Cambridge. After a formative sabbatical year in New York state where he worked at the Thomas J Watson Research Centre of IBM, he returned to Cambridge where his research activity grew rapidly. He moved to the Cavendish Laboratory where he joined the Department of Engineering and established the Microelectronics Research Centre, sponsored by Hitachi. In 1990, he was elected a Fellow of the Royal Academy of Engineering, in 1992 he was promoted to Professor of Microelectronics, and in 1996 he was awarded a Doctor of Science degree from the University of Cambridge.
Professor Ahmed died peacefully at home, surrounded by his wife and family on 23 October 2024. He is survived by his wife, Anne; his children, Ayesha, Rehana and Imran; his grandchildren, Max, Jem, Keir and Maya; and his sister, Zubaida.
Read his full obituary on the Corpus Christi website and on the Department of Physics website.
Tributes have been paid to former Master of Corpus Christi College Professor Haroon Ahmed, who has died aged 88.
Professor Haroon Ahmed
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