Latest news with #UniversityofGeneva
Time of India
21-05-2025
- Science
- Time of India
James Webb Space Telescope identified Milky Way's cosmic twin from the universe's first billion years
Astronomers have discovered Zhúlóng, an enormous spiral galaxy observed as it was just 12.8 billion years ago, challenging current theories about galaxy formation . Identified through the James Webb Space Telescope 's PANORAMIC survey, Zhúlóng shows a well-defined spiral structure—unexpected for such an early stage in the universe. Until now, spiral galaxies were rarely seen beyond 11.5 billion years ago. With a diameter of 62,000 light-years and a stellar mass comparable to the Milky Way, Zhúlóng suggests that mature, organized galaxies may have formed much earlier than scientists once believed. Zhúlóng: A mature galaxy born in the universe's first billion years Astronomer Mengyuan Xiao and his team from the University of Geneva state, "Zhúlóng reveals that mature galaxies formed much earlier than previously thought, within the first billion years following the Big Bang." Their research, published in Astronomy & Astrophysics, describes the galaxy's 'highly evolved structure,' which includes a classical quiescent bulge, a star-forming disk, and grand-design spiral arms. These spiral arms stretch from the nucleus to the galaxy's outer regions, defining its grand-design spiral shape. Such complex features are typically seen in older galaxies, making Zhúlóng's early development—just one billion years after the Big Bang—especially significant and challenging earlier models of galaxy formation. Consequences of James Webb Space Telescope identified-twin galaxy formation and evolution "Our discovery provides essential constraints for models of massive galaxy formation and the origins of spiral structures in the early universe," the researchers state. Earlier, it was assumed that the development of spiral galaxies was a slow process, with these structures forming predominantly after the first billion years of cosmic history. However, the detection of Zhúlóng suggests that the processes responsible for galaxy formation, such as star settling into disks and the formation of spiral arms, might have occurred much more rapidly. This challenges existing models and calls for a reassessment of factors like gas dynamics, star formation rates, and the role of dark matter halos. Zhúlóng's swift evolution within 800 million years after the Big Bang offers a new benchmark for astrophysical models and simulations aimed at understanding the early universe. by Taboola by Taboola Sponsored Links Sponsored Links Promoted Links Promoted Links You May Like Keep Your Home Efficient with This Plug-In elecTrick - Save upto 80% on Power Bill Learn More Undo A Milky Way twin like never before found by James Webb Space Telescope 'Zhúlóng stands out due to its striking resemblance to the Milky Way in terms of shape, size, and stellar mass,' says Xiao. With a diameter of around 62,000 light-years and a mass comparable to that of the Milky Way, Zhúlóng is a close cosmic relative despite its ancient origins. The galaxy's central black hole appears inactive, indicating a decline in its star formation rate, which is estimated to be between 20 and 155 solar masses per year. This suggests a shift from a highly active star-forming phase to a more mature, stable state. The galaxy's well-formed classical bulge and star-forming disk further confirm its advanced structural development, providing a rare glimpse into the Milky Way's early evolutionary stages. A new timeline perspective of Galaxy after James Webb Space Telescope's discovery The discovery of Zhúlóng in such an early stage suggests that massive galaxies could form up to ten times faster than previously believed. This revised timeline challenges traditional views on the pace of cosmic evolution during the first billion years after the Big Bang. Investigating the factors that enabled Zhúlóng's rapid formation will provide insights into the conditions of the early universe, including the availability of cold gas, star formation efficiency, and feedback from black holes or supernovae. As the JWST continues its study of the Cosmic Dawn, findings like Zhúlóng will enhance our understanding of how the universe evolved from its primordial state to a structured cosmos filled with complex galaxies like the Milky Way. Also read: 8 interesting scorpion facts that will blow your mind: Know about their characteristics, origin and more
Indian Express
26-04-2025
- Science
- Indian Express
What is a dead galaxy? Astronomers spot one that stopped forming stars 700M years after Big Bang
More than 13 billion years after the Big Bang, astronomers have found the most distant galaxy ever seen using the James Webb Space Telescope (JSWT), except that this one has already stopped forming stars. The JWST spotted light from this newly discovered 'dead galaxy' called RUBIES-UDS-QG-z7,(the Red Unknowns: Bright Infrared Extragalactic Survey). It is said to be the most distant and massive 'dead galaxy' to have been found till date. The discovery was made by an international team, led by astronomers from the University of Geneva (UNIGE) in Geneva, Switzerland. 'For a long time, scientists thought that only actively star-forming galaxies should be observed in the very early Universe. The James Webb space telescope now reveals that galaxies stopped forming stars earlier than expected,' according to a press release issued by the University on April 2, 2025. So, what is a dead galaxy? What leads to their formation? What is galaxy quenching? Why does the recent discovery matter? What is a dead galaxy? A galaxy that has stopped creating new stars is referred to as a 'dead galaxy'. This happens when a galaxy uses up its supply of gas, mainly hydrogen, which is essential for the birth of new stars. Without enough cold and dense gas, star formation becomes stagnant. Processes like stellar winds, supernovae, or black hole activity can also expel this gas. As a result, the galaxy slowly fades, filled with aging stars and no new ones to replace them. The oldest known 'dead' galaxy, JADES-GS-z7-01-QU, was spotted by the James Webb Space Telescope (JWST) in March last year. It stopped producing stars when the universe was just 700 million years old. How do galaxies grow and die? Galaxies grow by absorbing gas and converting it into new stars. A galaxy may be able to draw gas more effectively as its mass grows, which speeds up the formation of new stars as this growth is forever. Galaxies eventually go through a process known as 'quenching,' in which they stop forming stars and, in effect, stop growing. What is quenching? The biggest galaxies, which frequently have an elliptical shape, are particularly prone to quenching. Before star formation stops, these galaxies typically take a long period to form by building up large stellar populations. One of the most significant unsolved problems in astrophysics is what exactly causes galaxies to quench. 'Finding the first massive galaxies that stopped making stars in the early universe is important because it helps us learn how they were formed.' according to a research paper published by University of Geneva. 'Scientists found one such galaxy that made stars equal to 15 billion times the mass of the Sun, but stopped creating new stars,' it added. What next? At a distance of about 650 light-years, RUBIES-UDS-QG-z7's small physical size indicates a high stellar mass density that is equivalent to the maximum central densities found in quiescent galaxies at slightly lower redshifts (z ~2–5). It is possible that these galaxies will grow into the cores of the local universe's oldest and most massive elliptical galaxies. The Atacama Large Millimeter/submillimeter Array (ALMA), Earth's largest radio telescope project, which has 66 antennas situated in the Atacama Desert region of Northern Chile, may be able to assist the JWST in its research of RUBIES-UDS-QG-z7. 'The discovery of RUBIES-UDS-QG-z7 provides the first strong evidence that the centres of some nearby massive ellipticals may have already been in place since the first few hundred million years of the Universe,' the research paper read.
Yahoo
17-04-2025
- Science
- Yahoo
Meet Zhúlóng, The Milky Way 'Twin' That Shakes Up Our Cosmic Timeline
Back when the Universe was new, following the Big Bang some 13.8 billion years ago, galaxies took a bit of time to assemble themselves from the surrounding primordial soup. A new discovery right at the end of the Cosmic Dawn is challenging how long we thought that assembly took. JWST has spotted a huge, ultramassive galaxy as it appeared 12.8 billion years ago, so intricately structured that it can only belong to the most spectacular category of galaxies: the grand design spiral. The galaxy's name is Zhúlóng, after the Torch Dragon of Chinese myth, and its discovery has now been detailed in Astronomy & Astrophysics. "Zhúlóng shows that mature galaxies emerged much earlier than expected in the first billion years after the Big Bang," writes a team led by astronomer Mengyuan Xiao of the University of Geneva in Switzerland. "Our finding offers key constraints for models of massive galaxy formation and the origin of spiral structures in the early universe." In the Universe around us today, galaxies come in a number of different shapes and sizes. Lenticular galaxies are sort of blobby and formless, while spiral galaxies have defined spiral arms curving out from their centers. The grand design spiral galaxy is the most magnificently structured sort of galaxy, with prominent, well-formed and visible spiral arms curving away from a bright, well-defined galactic center; almost the platonic ideal of what a spiral galaxy should look like. We don't have a clear idea about when spiral galaxies first started to come together in the Universe, but they're pretty rare the further back in space-time we peer, and practically absent more than about 11.5 billion years ago. Zhúlóng was discovered serendipitously in data collected by JWST for its PANORAMIC survey, an observation campaign to observe galaxies in the Cosmic Dawn, the first billion years after the Big Bang. Although the survey has spotted other massive galaxies, Zhúlóng, the team says, is truly incredible. "It has a striking evolved morphology: a quiescent-like classical bulge + star-forming stellar disk + grand-design spiral arms (defined as spiral structures spanning the whole galaxy, from the nucleus to outskirts, with spiral arms starting at diametrically opposite points), already at 1 billion years after the Big Bang," they write in their paper. In addition, it's quite large for a galaxy in the early Universe, measuring some 62,000 light-years in diameter, with a mass comparable to that of the Milky Way. "What makes Zhúlóng stand out is just how much it resembles the Milky Way in shape, size and stellar mass," Xiao says. The black hole in its center seems to be quiescent, suggesting that the star formation rate of between 20 and 155 solar masses per year is slowing. All together, the data indicate a galaxy that has gone through the throes of formation and is settling down into a sedate, well-defined structure. The researchers believe that Zhúlóng represents the earliest example of a spiral galaxy seen to date. This suggests that a Milky Way-like galaxy can form far faster than we thought – around 10 times faster than such formation would take place in the local Universe. "The presence of all of these properties makes Zhúlóng very exceptional," the researchers write, "indicating the rapid formation and morphological evolution of massive galaxies in the early Universe." The discovery has been published in Astronomy & Astrophysics. An earlier version of this article was published in January 2025. New Form of Dark Matter May Explain Milky Way's Core Mysteries Strongest Evidence of Alien Life Yet Found 124 Light-Years Away Ghostly Rings of Dying Star Captured in Never-Before-Seen Detail by JWST
Yahoo
17-04-2025
- Science
- Yahoo
James Webb telescope discovers Zhúlóng, the Milky Way's long-lost 'twin' near the dawn of time
When you buy through links on our articles, Future and its syndication partners may earn a commission. When astronomers used the James Webb Space Telescope (JWST) to peer deep into the early universe, they made a serendipitous discovery: a galaxy that appears to be the Milky Way's ancient twin sibling waving its spiral arms back at us. In new images that capture light emitted just 1 billion years after the Big Bang, when the universe was roughly one-fourteenth its current age, the newly discovered galaxy appears fully formed, with a central bulge of old stars, a vibrant disk of stellar newborns, and two distinct spiral arms. Given its recognizable features and impressive size, the researchers have dubbed this galaxy the most distant Milky Way "twin" ever observed. The detection of such a fully formed spiral galaxy so early in cosmic time adds to many recent JWST discoveries that challenge our best theories of cosmology, which predict that large galaxies like this should take several billion years to form through an arduous series of smaller galaxy mergers. A full description of the galaxy — nicknamed Zhúlóng, after a mythical Chinese sun dragon whose eyes controlled the day and night cycle — was published April 16 in the journal Astronomy & Astrophysics. "What makes Zhúlóng stand out is just how much it resembles the Milky Way — both in shape, size, and stellar mass," first study author Mengyuan Xiao, a postdoctoral researcher at the University of Geneva, said in a statement. While Zhúlóng is unquestionably older than the Milky Way, it could be mistaken for our galaxy's "little" sibling. The new research estimates that Zhúlóng's star-forming disk measures about 60,000 light-years across, compared with our galaxy's 100,000 light-year breadth, and it contains about 100 billion solar masses, compared with the Milky Way's 1.5 trillion. Still, Zhúlóng is by far the largest Milky Way look-alike spotted at such an early time in the universe's history. It formed more than a billion years earlier than the similarly shaped spiral galaxy Ceers-2112, which JWST discovered in 2023 at about 11.7 billion light-years from Earth. Related: 42 jaw-dropping James Webb Space Telescope images No genealogical tests were needed to find this long-lost sibling; the researchers discovered it by accident in PANORAMIC, a wide-field survey of billions of distant objects. The survey was taken in JWST's unique "pure parallel" mode — essentially, a way for the telescope to use two of its infrared instruments simultaneously to observe two different regions of space at once. "This allows JWST to map large areas of the sky, which is essential for discovering massive galaxies, as they are incredibly rare," study co-author Christina Williams, an assistant astronomer at the National Science Foundation's NOIRLab and principal investigator of the PANORAMIC survey, said in the statement. The serendipitous discovery of Zhúlóng adds fuel to an ongoing cosmological fire started by JWST several years ago. The telescope's observations of the early universe consistently show that objects there, including gargantuan galaxies and supermassive black holes, seem to have grown too big, too fast for our current best theories to explain. It's thought that the Milky Way took several billion years to form, while Zhúlóng seems to have achieved a similar shape and size in less than 1 billion years. How this is possible remains "an open question," the team wrote in the study. RELATED STORIES —Rare quadruple supernova on our 'cosmic doorstep' will shine brighter than the moon when it blows up in 23 billion years —Atacama Telescope reveals earliest-ever 'baby pictures' of the universe: 'We can see right back through cosmic history' —Scientists discover smallest galaxy ever seen: 'It's like having a perfectly functional human being that's the size of a grain of rice' "This discovery shows how JWST is fundamentally changing our view of the early universe," study co-author Pascal Oesch, an associate professor of astronomy at the University of Geneva and co-principal investigator of the PANORAMIC program, concluded in the statement. The researchers are proposing follow-up observations with JWST, as well as with the ground-based Atacama Large Millimeter/submillimeter Array in the Chilean desert, to get to know our galaxy's long-lost twin even better.
Yahoo
15-04-2025
- Health
- Yahoo
Using smartphones may protect older adults against cognitive problems like dementia as they age
Older adults who are digitally savvy may be less likely to face cognitive impairment as they age, a new study suggests. The average 80-year-old has witnessed an extraordinary boom in personal technology throughout their lifetime: born years before colour television, they're growing old in the TikTok era. For years, scientists have fretted over whether the ubiquity of tech in daily life harms or helps our minds as we age. The research, published in the journal Nature Human Behaviour, is the latest to tip the scales toward the 'help' category. Related How to lower your dementia risk as cases expected to rise by 2060 It pooled data from 57 studies spanning more than 411,000 adults aged 50 and older from around the world, all of whom had either a cognitive diagnosis or testing. The researchers called these older adults, aged 68 on average, 'digital pioneers' because they didn't have access to the Internet during childhood. Older people who used smartphones, computers, or the Internet had a lower risk of cognitive impairment than those who stayed away from devices, the analysis shows. Over several years of follow-up, tech-savvy seniors were also less likely to experience cognitive decline. The link between tech use and brain health was as strong – or stronger – than other factors that seem to protect against dementia, including lower blood pressure, exercise, being more highly educated, and having mentally stimulating hobbies. Related Over 75% of 3 and 4-year-olds in Europe get too much screen time and not enough sleep and exercise The findings are 'completely timely' given countries around the world are ageing, Maximilian Haas, who leads a research group on technology and cognitive function at the University of Geneva, told Euronews Health. And 'it's understandable that technology use could evoke and provoke comparable effects compared to these other factors,' added Haas, who was not involved with the new study. Notably, the new study's results held up even when the researchers accounted for issues like socioeconomic status, overall health, and social support, which could also boost brain health. The findings are in line with a study Haas published last year, which found that older adults in Switzerland who had stronger memories were more likely to be regular Internet users. Meanwhile another analysis of about 463,000 people in the United Kingdom concluded that there is no 'obvious association' between computer use and dementia, though more research is needed to disentangle the potential impact of too much screen time on brain health. Related Scientists believe people who work in these two jobs have a lower risk of Alzheimer's These studies favour the idea that our digital lives could promote more complex thinking, skills, and social connections, net positives for brain health. The benefits, referred to as 'technological reserve', are often contrasted with the 'digital dementia' theory, which argues that an over-reliance on technology decimates memory, attention, and problem-solving abilities, particularly among younger people. But in reality, 'there's both positive and negative sides to screen exposure,' Haas said, adding that moderation is key. When it comes to cognitive function, 'it's too little or too much that makes the difference here'.
