Latest news with #UniversityofLisbon
Yahoo
a day ago
- Science
- Yahoo
Tectonic Plates Can ‘Infect' One Another with Earth-Shaking Subduction Zones
Subduction zones, where one tectonic plate dives underneath another, drive the world's most devastating earthquakes and tsunamis. How do these danger zones come to be? A study in Geology presents evidence that subduction can spread like a contagion, jumping from one oceanic plate to another—a hypothesis previously difficult to prove. This result 'is not just speculation,' says University of Lisbon geologist João Duarte, who was not involved in the research. 'This study builds an argument based on the geological record.' Because subduction drags crust deep into the earth, its beginnings are hard to examine. The new study provides a rare ancient example of potential subduction 'infection.' Its authors say they've discovered evidence that neighboring collisions triggered East Asia's 'Ring of Fire,' a colossal subduction system currently fueling earthquakes and volcanoes from Alaska to the southern Indian Ocean. [Sign up for Today in Science, a free daily newsletter] Nearly 300 million years ago China was a scattering of islands separated by the ancient Tethys and Asian oceans. Established subduction zones consumed these oceans, welding the landmasses into a new continent and raising mountains from Turkey to China. By 260 million years ago this subduction seems to have spread and begun pulling down the neighboring Pacific plate. 'The dying act of those closing oceans may have been to infect the Pacific plate and start it subducting westward under the Asian continent,' says study lead author Mark Allen, a geologist at Durham University in England. 'In one form or another, it's been diving down ever since.' The smoking gun in this case is the 'Dupal anomaly,' identified by a geochemical fingerprint from the ancient Tethys Ocean and what is now the Indian Ocean. When the study authors unexpectedly found this signature in volcanic rocks from the western Pacific, they surmised that material from the Tethys had spread eastward across a plate boundary from one subduction zone to another—triggering the neighboring plate's descent. 'It's like seeing someone's fingerprint at a crime scene,' Allen says. But the mechanism of spread remains mysterious. The researchers suspect that transform faults—boundaries where plates slide past one another, like the San Andreas Fault—may act as weak spots where slight changes in collision angle or speed can destabilize dense oceanic crust, causing it to sink. Duarte compares the scenario to aluminum foil in water. 'The foil floats,' he says, 'but the slightest tap will cause it to sink.' If subduction spreads this way, could the Atlantic Ocean's relatively quiet plate margins be next? The massive 1755 Lisbon earthquake hints at early subduction invasion there. Duarte suggests parts of Iberia and the Caribbean are undergoing this process's initial stages: 'In another 100 million years a new Atlantic 'Ring of Fire' may form—just as it once did in the Pacific.'
Scientific American
a day ago
- Science
- Scientific American
Tectonic Plates Can ‘Infect' One Another with Earth-Shaking Subduction Zones
Subduction zones, where one tectonic plate dives underneath another, drive the world's most devastating earthquakes and tsunamis. How do these danger zones come to be? A study in Geology presents evidence that subduction can spread like a contagion, jumping from one oceanic plate to another—a hypothesis previously difficult to prove. This result 'is not just speculation,' says University of Lisbon geologist João Duarte, who was not involved in the research. 'This study builds an argument based on the geological record.' Because subduction drags crust deep into the earth, its beginnings are hard to examine. The new study provides a rare ancient example of potential subduction 'infection.' Its authors say they've discovered evidence that neighboring collisions triggered East Asia's 'Ring of Fire,' a colossal subduction system currently fueling earthquakes and volcanoes from Alaska to the southern Indian Ocean. On supporting science journalism If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today. Nearly 300 million years ago China was a scattering of islands separated by the ancient Tethys and Asian oceans. Established subduction zones consumed these oceans, welding the landmasses into a new continent and raising mountains from Turkey to China. By 260 million years ago this subduction seems to have spread and begun pulling down the neighboring Pacific plate. 'The dying act of those closing oceans may have been to infect the Pacific plate and start it subducting westward under the Asian continent,' says study lead author Mark Allen, a geologist at Durham University in England. 'In one form or another, it's been diving down ever since.' The smoking gun in this case is the 'Dupal anomaly,' identified by a geochemical fingerprint from the ancient Tethys Ocean and what is now the Indian Ocean. When the study authors unexpectedly found this signature in volcanic rocks from the western Pacific, they surmised that material from the Tethys had spread eastward across a plate boundary from one subduction zone to another—triggering the neighboring plate's descent. 'It's like seeing someone's fingerprint at a crime scene,' Allen says. But the mechanism of spread remains mysterious. The researchers suspect that transform faults—boundaries where plates slide past one another, like the San Andreas Fault—may act as weak spots where slight changes in collision angle or speed can destabilize dense oceanic crust, causing it to sink. Duarte compares the scenario to aluminum foil in water. 'The foil floats,' he says, 'but the slightest tap will cause it to sink.' If subduction spreads this way, could the Atlantic Ocean 's relatively quiet plate margins be next? The massive 1755 Lisbon earthquake hints at early subduction invasion there. Duarte suggests parts of Iberia and the Caribbean are undergoing this process's initial stages: 'In another 100 million years a new Atlantic 'Ring of Fire' may form—just as it once did in the Pacific.'
Morocco World
26-05-2025
- Entertainment
- Morocco World
‘Horizons Croisés': Hajar Lmortaji's Art Exhibition Merges Rabat and Lisbon
Rabat – Moroccan artist Hajar Lmortaji is presenting a new exhibition titled 'Horizons Croisés' (Crossed Horizons) at the National Gallery Bab Rouah in Rabat. The show, which opened on Friday and runs through May 31, brings together abstract works inspired by the cities of Rabat and Lisbon. The exhibition aims to explore what connects the two capitals, drawing on shared cultural elements, personal experiences, and visual symbols. Lmortaji uses abstraction to represent emotional and symbolic themes, including human presence, memory, and dream-like states. According to the artist, the exhibition reflects impressions and feelings shaped by time spent in both cities. In a statement to the Moroccan news agency MAP, she said the works were guided by lived experiences, such as listening to fado music in Lisbon or walking under jacaranda trees in Rabat. Her paintings incorporate floral forms, fragments of human figures, and textures that suggest both emotion and structure. One recurring motif is the azulejo, the traditional ceramic tile found throughout Portuguese architecture. Lmortaji describes it as a 'thread' linking her work to Lisbon, evoking patience, craftsmanship, and place-based memory. While grounded in abstraction, the exhibition hints at a broader interest in how cities shape artistic expression and personal identity. The works do not directly depict either Rabat or Lisbon but instead attempt to translate emotional and cultural similarities into visual form. 'I simply let my emotions guide my creation,' she said, noting that the exhibition is my way of sharing those feelings with the public and showing the deep connection between these two cities. Lmortaji is a self-taught artist who paints as a form of personal expression and therapy. Born in Rabat and a Ph.D. holder from the University of Lisbon, she began painting as a child and developed her own unique style over time. She focuses on abstract and figurative expressionism, using colors and emotions to guide her work. Tags: Arthajar lmortajiLisbonRabat
Yahoo
03-05-2025
- Science
- Yahoo
Scientists Say They've Built a "Black Hole Bomb"
Physicists say they've built the first-ever "black hole bomb" — an ominous-sounding concept that dates back to the late 1960s, but that serves as little more than a harmless proof of concept. As New Scientist reports, the idea is to boost energy with a black hole, then trap it with mirrors until you get an explosion. However, what the team created in a lab is a harmless test, without a real black hole that could suck the planet into oblivion. And instead of looking for ways to wipe enemy alien civilizations off the map, the goal of the research is to study how black holes drag and accelerate the fabric of space-time around themselves, a phenomenon first theorized by physicist Roger Penrose in 1969. In 1971, Belarusian physicist Yakov Zel'dovich came up with a spinning system to investigate whether the rotational energy of a black hole could be extracted by exploiting the extreme conditions inside it without breaking the laws of conservation of energy. At the scale of a real black hole light-years away, the energy generated and released could be as much as a supernova, according to existing theories. In the latest experiment, detailed in a draft paper awaiting peer review, coauthor and University of Southampton physics professor Hendrik Ulbricht and his colleagues investigated the "Zel'dovich effect," using a cylindrical mirror to amplify energy and create a positive feedback loop. Starting in 2020, during the height of the COVID-19 lockdowns, Ulbricht built an early proof of concept out of a rotating aluminum cylinder and magnetic fields. "Everything was closed, and I was really bored and I wanted to do something, so I built the setup and started to do these experiments, and I saw amplification," he told New Scientist. "I was so super excited that, actually, you could say it rescued me during COVID." With the help of a team he assembled, the researchers built on his vision, rotating magnetized metal coils around a cylinder at high speeds. And surprisingly, the team ended up with an even larger magnetic field than they started with. "You throw a low-frequency electromagnetic wave against a spinning cylinder, who would think that you get back more than what you threw in?" University of Lisbon professor of physics Vitor Cardoso, who was not involved in the research, told New Scientist. "It's totally mind boggling." Even without a magnetic field being generated by the coils, the setup would still generate a signal, indicating the experiment seemingly confirmed existing theories about how energy behaves near a black hole. "We're basically generating a signal from noise, and that is the same thing that happens in the black hole bomb proposal," Ulbricht told New Scientist. The team hopes that their research could allow us to get a better idea of how black holes energize nearby particles, and could even shed light on dark matter, the mysterious stuff believed to make up about 27 percent of the matter in the universe. While we're still far from harvesting energy from a real black hole — or even capturing or creating one in the first place — the team hopes their research is a small step in the right direction. "A challenge for the future remains the observation of spontaneous [electromagnetic] wave generation and runaway amplification seeded from the vacuum," the team wrote in their paper. "However, based on the results presented here, this now remains a purely technological (even if very hard) feat." More on black holes: Scientist Says He Found Evidence Our Entire Universe Is Trapped Inside a Black Hole
Yahoo
28-04-2025
- Science
- Yahoo
Scientists create world's first 'black hole bomb'
Scientists have created the world's first 'black hole bomb' and it could help experts better understand the space phenomenon. The theory of the black hole bomb was first proposed by physicist Roger Penrose back in 1971. The idea was that the angular momentum of a moving black hole and the energy that creates could be transferred to a particle close to the black hole. Two years on from that, another scientist, Yakov Zeldovich, made the discovery that a similar process could take place in other situations. This includes things like light moving around a fast-spinning metal cylinder. Zeldovich also believed that if you surround the rotating cylinder with a cylindrical mirror then the energy could be reflected and built up in a positive feedback loop. This will occur until the energy is vented out or it explodes, producing a black hole bomb. This theory of extracting energy has finally been put to the test, although thankfully, this was on a much smaller scale. Instead of using a real black hole in outer space to try out the idea, instead physicists experimented with a safe toy model, although the principles are identical. Vitor Cardoso, who is from the University of Lisbon in Portugal, spoke to New Scientist about the revelation, where he said: 'You throw a low-frequency electromagnetic wave against a spinning cylinder, who would think that you get back more than what you threw in? It's totally mind boggling.' He went on to say: 'Having accurate measurements in the laboratory of this process really allows you to confidently say, 'yes, this must happen in black hole physics as well'.' Hendrik Ulbricht, who conducted the experiment with a team at the University of Southampton in the UK, explained: 'We're basically generating a signal from noise, and that is the same thing that happens in the black hole bomb proposal.' This test has the potential to help scientists gain a better understanding of how the phenomenon works and could lead to more insight on things including dark matter. Cardoso added: 'If new fields exist, we should be seeing, for instance, gravitational waves being emitted from this cloud around black holes, or we should see black holes spinning down because they're giving their energy away to these new particles. 'So superradiance is turning black holes into particle detectors, and much better particle detectors than [the Large Hadron Collider at] CERN can be for this type of dark matter.'
