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Yahoo
13-05-2025
- Science
- Yahoo
How to Build a ‘Black Hole Bomb'
A bomb from a black hole would probably be the most destructive weapon in the universe. Hypothetically, it could be created by wrapping one of these cosmic monsters in mirrors and waiting for it to go 'boom.' Now Hendrik Ulbricht of the University of Southampton in England and his colleagues have demonstrated this principle, called superradiance, in the lab using a rotating metal cylinder instead of a black hole. They submitted their results, which have not yet been peer-reviewed, to the preprint server in late March. 'This work shows that a 'black hole bomb' can actually be built in the laboratory,' says physicist Vitor Cardoso of the Niels Bohr Institute in Denmark, who was not involved in the study. 'It thus provides a solid basis for studying the entire physics of black holes.' Among the strangest objects in the universe, black holes pack so much mass into such a small space that they can radically warp spacetime. A black hole's gravitational pull is so strong that within a certain distance, nothing can escape it—not even light. Theorist Roger Penrose is one of the pioneers who first studied black holes mathematically in detail—work for which he shared the Nobel Prize in Physics in 2020. And amid that early work, he realized something surprising. [Sign up for Today in Science, a free daily newsletter] As Penrose knew, nothing stands still in our cosmos, not even black holes. These massive monsters can spin, distorting spacetime in the process to form a kind of vortex. An approaching object can be caught up in this vortex and spiral around the spinning black hole. Even before the object passes the event horizon, beyond which not even light can escape gravity's clutches, it reaches an area that physicists call the 'ergosphere.' There the object would have to move faster than light to escape the rotation around the black hole. This ergosphere is a strange place, as Penrose noted, because objects there can possess negative energy. A particle, for example, could split into two equal-but-opposite parts: one with negative energy and another with positive energy. The former would then crash into the black hole (thus reducing the black hole's energy), allowing the latter to escape the cosmic behemoth's mighty grip. An external observer would see a particle with a certain energy falling toward the black hole, only to apparently rebound outward with higher energy. The black hole loses part of its rotational energy in the process. In principle, this would allow black holes to serve as gigantic sources of energy. The process could not only imbue massive objects with more energy but also amplify electromagnetic waves in a phenomenon called superradiance. This realization spurred some physicists to even imagine how advanced alien civilizations might use superradiance to generate energy. But despite how relatively simple it is to describe on paper, no one knew how the signal of superradiance could be observed in real black holes. Thus, the concept initially remained mere speculation. In 1971, however, two years after Penrose first described this phenomenon, physicist Yakov Zel'dovich published research that suggested that black holes aren't the only objects that can be tapped as superradiant energy sources. Any rotating, axially symmetrical body that absorbs electromagnetic radiation—such as a metal cylinder—can also exhibit superradiance under certain circumstances. 'Roughly speaking, the rotating absorber must rotate faster than the phase rotation of the incident radiation,' explains physicist Maria Chiara Braidotti of the University of Glasgow in Scotland, who was involved in the latest work. 'If this condition is met, the absorption coefficient of the cylinder changes sign, thus amplifying the radiation.' Zel'dovich even went one step further by showing that superradiance could also take place in a vacuum and wouldn't require an incoming electromagnetic wave. That's because on quantum scales the vacuum is anything but empty. At any time, pairs of virtual particles and antiparticles can pop into existence, although they typically immediately annihilate each other again. The phenomenon is known as vacuum fluctuation. And these fluctuations could also be amplified in the vicinity of black holes —or a rotating metal cylinder. 'Stephen Hawking didn't believe this idea and tried to refute it,' explains Marion Cromb, a researcher in Ulbricht's group at the University of Southampton and a contributor to the new work. 'Not only did [Hawking] admit that Zel'dovich was right but he was also able to prove that even nonrotating black holes—without an ergosphere—spontaneously emit radiation.' This realization led to the discovery of Hawking radiation. According to the theoretical calculations, however, vacuum-based superradiance would be so faint that it could not be detected—unless, that is, it was somehow amplified. As Zel'dovich described, the rotating body (black hole or metal cylinder) could be encased in mirrors to reflect the amplified radiation back to the rotating body, intensifying it over and over again. As physicists William Press and Saul Teukolsky realized, so much energy could accumulate inside the mirrors that a gigantic explosion would occur. Press and Teukolsky, therefore, referred to the setup as a black hole bomb. Depending on how much rotational energy the black hole or the metal cylinder has, a result other than a gigantic explosion is conceivable, though. Cardoso and his colleagues described this possibility in a paper published in 2004 that showed how superradiance can cease if the black hole or metal cylinder loses too much angular momentum, thus defusing the explosion. Ulbricht, Braidotti and their colleagues now wanted to test all these theoretical predictions in the laboratory. 'Originally, we thought it would be too difficult to observe the actual effect,' Braidotti says, nothing that a cylinder would have to rotate so fast that it would be destroyed in the process. For this reason, she initially turned her attention to simpler systems in which superradiance can occur, including a setup with sound waves. 'The breakthrough was our noticing how to reduce the frequencies of electromagnetic fields in a very simple way so that they are smaller than the rotation frequencies of the metal cylinders,' Ulbricht explains. The researchers only needed alternating current circuits for this. 'This finding opened up the possibility of conducting the experiment with electromagnetic waves,' Braidotti says. The team then turned its attention to electromagnetic superradiance. 'The experimental setup itself is quite simple: it consists of a rotating cylinder and the stator coils of a commercially available induction motor, combined with some capacitors and resistors,' Cromb says. These devices were placed around the metal cylinder to generate a magnetic field inside it, which produced electromagnetic radiation. At the same time, these devices also served as mirrors because they reflected the electromagnetic waves back toward the cylinder. 'The biggest difficulty was that things were constantly exploding,' Cromb says. 'It was a balancing act between measuring a reasonable signal and overloading the system. When the current through the coils became too high, the resistors in the circuit exceeded their rated voltage and burned out. This interrupted the electrical circuit, thus destroying the 'mirror.'' The researchers initially feared that these overloads would prevent any observation of superradiance. But they were lucky. 'The reinforcement was large enough to overcome the loss and enter the area of instability,' Cromb says. In fact, the team was able to show that the voltage in their structure increased exponentially, as predicted by Zel'dovich. This underpins the researchers' claim of the first-ever lab-based demonstration of an electromagnetic version of a black hole bomb. Note, however, that despite the martial connotations of the name, the 'bomb' Ulbricht and his team built in their lab isn't anything like a military-grade munition—or even a firecracker. It would be quite useless as a weapon because its yield is only on the order of a millijoule of energy—that is, about the same amount involved in pressing a single key on a mechanical keyboard. Next, Cromb and the team used their setup to study whether superradiance can also take place in a vacuum: Would an electromagnetic signal arise in their apparatus even without a magnetic field? Because the experiment took place at room temperature, thermal fluctuations overshadowed any vacuum fluctuations—meaning that the team could not directly detect the latter. But that very same thermal background noise, the researchers realized, would spontaneously generate electromagnetic waves that could theoretically be amplified. And that is what they did manage to demonstrate: by choosing the appropriate rotation speed of the cylinder, they generated electromagnetic waves out of nowhere, so to speak. Their work also confirmed the 'defusing' scenario predicted by Cardoso: the metal cylinder was able to lose enough rotational energy to halt superradiance and stave off any explosion. According to Ulbricht, the most special thing about the work is its sheer simplicity. 'Many physicists think that all the simple experiments have already been done and that new insights into the fundamentals of physics can only come from very complex and very expensive projects,' he says. 'We proved the opposite.' 'I didn't expect that someone would be able to carry out such an experiment now,' Cardoso says. On the day the new work was posted to he recalls, he was giving a series of lectures at Bangalore University in India. 'I talked about superradiance and told the audience that no one had ever proven the electromagnetic superradiance or the bomb effect in the laboratory. So you can imagine my surprise when I saw the paper shortly afterwards!' The new work could lead to deeper insights about black holes, Cardoso says. 'Superradiance is a little-known classical effect that plays an important role in the physics of black holes,' he explains. For example, extremely light particles, such as axions or special types of photons considered candidates for dark matter, could absorb the rotational energy of black holes, amplifying their signals. 'This means that black holes can be used as gigantic particle detectors,' Cardoso explains. With a lab-based black hole bomb, physicists could test such hypotheses more precisely than ever before. In the future, Ulbricht would like to carry out the quantum version of the experiment, which would entail observing the spontaneous generation of electromagnetic waves and their amplification from the vacuum. Such direct experiments with vacuum fluctuations could open up completely new possibilities for the scientific community and the world, he says, potentially representing 'a major breakthrough for physics.' Perhaps, Ulbricht muses, that work could allow researchers 'in a few decades to understand whether it is possible in principle to generate energy from the vacuum—which would be an inexhaustible new source of energy.'
Scientific American
13-05-2025
- Science
- Scientific American
Physicists Build a ‘Black Hole Bomb' in the Laboratory
A bomb from a black hole would probably be the most destructive weapon in the universe. Hypothetically, it could be created by wrapping one of these cosmic monsters in mirrors and waiting for it to go 'boom.' Now Hendrik Ulbricht of the University of Southampton in England and his colleagues have demonstrated this principle, called superradiance, in the lab using a rotating metal cylinder instead of a black hole. They submitted their results, which have not yet been peer-reviewed, to the preprint server in late March. 'This work shows that a 'black hole bomb' can actually be built in the laboratory,' says physicist Vitor Cardoso of the Niels Bohr Institute in Denmark, who was not involved in the study. 'It thus provides a solid basis for studying the entire physics of black holes.' Among the strangest objects in the universe, black holes pack so much mass into such a small space that they can radically warp spacetime. A black hole's gravitational pull is so strong that within a certain distance, nothing can escape it—not even light. Theorist Roger Penrose is one of the pioneers who first studied black holes mathematically in detail—work for which he shared the Nobel Prize in Physics in 2020. And amid that early work, he realized something surprising. 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. As Penrose knew, nothing stands still in our cosmos, not even black holes. These massive monsters can spin, distorting spacetime in the process to form a kind of vortex. An approaching object can be caught up in this vortex and spiral around the spinning black hole. Even before the object passes the event horizon, beyond which not even light can escape gravity's clutches, it reaches an area that physicists call the 'ergosphere.' There the object would have to move faster than light to escape the rotation around the black hole. This ergosphere is a strange place, as Penrose noted, because objects there can possess negative energy. A particle, for example, could split into two equal-but-opposite parts: one with negative energy and another with positive energy. The former would then crash into the black hole (thus reducing the black hole's energy), allowing the latter to escape the cosmic behemoth's mighty grip. An external observer would see a particle with a certain energy falling toward the black hole, only to apparently rebound outward with higher energy. The black hole loses part of its rotational energy in the process. Black Hole Mining and Superradiance In principle, this would allow black holes to serve as gigantic sources of energy. The process could not only imbue massive objects with more energy but also amplify electromagnetic waves in a phenomenon called superradiance. This realization spurred some physicists to even imagine how advanced alien civilizations might use superradiance to generate energy. But despite how relatively simple it is to describe on paper, no one knew how the signal of superradiance could be observed in real black holes. Thus, the concept initially remained mere speculation. In 1971, however, two years after Penrose first described this phenomenon, physicist Yakov Zel'dovich published research that suggested that black holes aren't the only objects that can be tapped as superradiant energy sources. Any rotating, axially symmetrical body that absorbs electromagnetic radiation—such as a metal cylinder—can also exhibit superradiance under certain circumstances. 'Roughly speaking, the rotating absorber must rotate faster than the phase rotation of the incident radiation,' explains physicist Maria Chiara Braidotti of the University of Glasgow in Scotland, who was involved in the latest work. 'If this condition is met, the absorption coefficient of the cylinder changes sign, thus amplifying the radiation.' Zel'dovich even went one step further by showing that superradiance could also take place in a vacuum and wouldn't require an incoming electromagnetic wave. That's because on quantum scales the vacuum is anything but empty. At any time, pairs of virtual particles and antiparticles can pop into existence, although they typically immediately annihilate each other again. The phenomenon is known as vacuum fluctuation. And these fluctuations could also be amplified in the vicinity of black holes —or a rotating metal cylinder. 'Stephen Hawking didn't believe this idea and tried to refute it,' explains Marion Cromb, a researcher in Ulbricht's group at the University of Southampton and a contributor to the new work. 'Not only did [Hawking] admit that Zel'dovich was right but he was also able to prove that even nonrotating black holes—without an ergosphere—spontaneously emit radiation.' This realization led to the discovery of Hawking radiation. According to the theoretical calculations, however, vacuum-based superradiance would be so faint that it could not be detected—unless, that is, it was somehow amplified. As Zel'dovich described, the rotating body (black hole or metal cylinder) could be encased in mirrors to reflect the amplified radiation back to the rotating body, intensifying it over and over again. As physicists William Press and Saul Teukolsky realized, so much energy could accumulate inside the mirrors that a gigantic explosion would occur. Press and Teukolsky, therefore, referred to the setup as a black hole bomb. Depending on how much rotational energy the black hole or the metal cylinder has, a result other than a gigantic explosion is conceivable, though. Cardoso and his colleagues described this possibility in a paper published in 2004 that showed how superradiance can cease if the black hole or metal cylinder loses too much angular momentum, thus defusing the explosion. Explosions in the Laboratory Ulbricht, Braidotti and their colleagues now wanted to test all these theoretical predictions in the laboratory. 'Originally, we thought it would be too difficult to observe the actual effect,' Braidotti says, nothing that a cylinder would have to rotate so fast that it would be destroyed in the process. For this reason, she initially turned her attention to simpler systems in which superradiance can occur, including a setup with sound waves. 'The breakthrough was our noticing how to reduce the frequencies of electromagnetic fields in a very simple way so that they are smaller than the rotation frequencies of the metal cylinders,' Ulbricht explains. The researchers only needed alternating current circuits for this. 'This finding opened up the possibility of conducting the experiment with electromagnetic waves,' Braidotti says. The team then turned its attention to electromagnetic superradiance. 'The experimental setup itself is quite simple: it consists of a rotating cylinder and the stator coils of a commercially available induction motor, combined with some capacitors and resistors,' Cromb says. These devices were placed around the metal cylinder to generate a magnetic field inside it, which produced electromagnetic radiation. At the same time, these devices also served as mirrors because they reflected the electromagnetic waves back toward the cylinder. 'The biggest difficulty was that things were constantly exploding,' Cromb says. 'It was a balancing act between measuring a reasonable signal and overloading the system. When the current through the coils became too high, the resistors in the circuit exceeded their rated voltage and burned out. This interrupted the electrical circuit, thus destroying the 'mirror.'' The researchers initially feared that these overloads would prevent any observation of superradiance. But they were lucky. 'The reinforcement was large enough to overcome the loss and enter the area of instability,' Cromb says. In fact, the team was able to show that the voltage in their structure increased exponentially, as predicted by Zel'dovich. This underpins the researchers' claim of the first-ever lab-based demonstration of an electromagnetic version of a black hole bomb. Note, however, that despite the martial connotations of the name, the 'bomb' Ulbricht and his team built in their lab isn't anything like a military-grade munition—or even a firecracker. It would be quite useless as a weapon because its yield is only on the order of a millijoule of energy—that is, about the same amount involved in pressing a single key on a mechanical keyboard. Radiation-Free Superradiance? Next, Cromb and the team used their setup to study whether superradiance can also take place in a vacuum: Would an electromagnetic signal arise in their apparatus even without a magnetic field? Because the experiment took place at room temperature, thermal fluctuations overshadowed any vacuum fluctuations—meaning that the team could not directly detect the latter. But that very same thermal background noise, the researchers realized, would spontaneously generate electromagnetic waves that could theoretically be amplified. And that is what they did manage to demonstrate: by choosing the appropriate rotation speed of the cylinder, they generated electromagnetic waves out of nowhere, so to speak. Their work also confirmed the 'defusing' scenario predicted by Cardoso: the metal cylinder was able to lose enough rotational energy to halt superradiance and stave off any explosion. According to Ulbricht, the most special thing about the work is its sheer simplicity. 'Many physicists think that all the simple experiments have already been done and that new insights into the fundamentals of physics can only come from very complex and very expensive projects,' he says. 'We proved the opposite.' 'I didn't expect that someone would be able to carry out such an experiment now,' Cardoso says. On the day the new work was posted to he recalls, he was giving a series of lectures at Bangalore University in India. 'I talked about superradiance and told the audience that no one had ever proven the electromagnetic superradiance or the bomb effect in the laboratory. So you can imagine my surprise when I saw the paper shortly afterwards!' The new work could lead to deeper insights about black holes, Cardoso says. 'Superradiance is a little-known classical effect that plays an important role in the physics of black holes,' he explains. For example, extremely light particles, such as axions or special types of photons considered candidates for dark matter, could absorb the rotational energy of black holes, amplifying their signals. 'This means that black holes can be used as gigantic particle detectors,' Cardoso explains. With a lab-based black hole bomb, physicists could test such hypotheses more precisely than ever before. In the future, Ulbricht would like to carry out the quantum version of the experiment, which would entail observing the spontaneous generation of electromagnetic waves and their amplification from the vacuum. Such direct experiments with vacuum fluctuations could open up completely new possibilities for the scientific community and the world, he says, potentially representing 'a major breakthrough for physics.' Perhaps, Ulbricht muses, that work could allow researchers 'in a few decades to understand whether it is possible in principle to generate energy from the vacuum—which would be an inexhaustible new source of energy.'
Forbes
15-04-2025
- Business
- Forbes
Addressing The Major, Global Challenges From Denmark
We live in an age defined by paradox. Technological advancement is accelerating at breakneck speed, and yet when it comes to one of the most essential sectors of human existence – healthcare – we are still playing catch-up. With ageing populations, soaring demand for preventative care and a shrinking pool of medical professionals (about 25% of whom are considering a career change), the global healthcare system is teetering on the edge. And while many look to Silicon Valley for salvation, an unlikely tech saviour is quietly brewing up north. Enter Denmark. Yes, Denmark is far more than charming bike lanes and pastry-fuelled contentment. It has quietly emerged as one of Europe's most promising tech hubs, and if you're looking for examples of the kind of innovation that might just save the world - or at least improve your next visit to the hospital - then you need look no further than Corti. A Nation of Builders, From Longboats to Language Models Let's rewind a bit. The Danes have always punched above their weight. The Vikings weren't just warriors; they were also designing some of the most effective seafaring vessels of their time. Innovation is part of Denmark's DNA, and centuries later, that legacy is still alive. Take a stroll through Copenhagen and you will find world-class institutions like the Niels Bohr Institute, the Technical University of Denmark (DTU), and Copenhagen University. These aren't just ivory towers – they are hothouses for deep science, mathematics, physics, and increasingly, AI. Denmark also gave us insulin, Bluetooth, Google Maps (thanks to a Danish acquisition), PHP and some of the most advanced signal processing tech used in hearing aids today. Not bad for a country with fewer people than London. This unique combination of scientific heritage, export-oriented thinking and a Viking-level ambition to explore and conquer makes Denmark the perfect launchpad for global tech ventures. Which brings us back to Corti. Corti: Building the AI Enterprise Models Healthcare Deserves Corti was founded by two Danes, Andreas Cleve and Lars Maaløe, who had a radical idea: what if you built a Generative AI platform specifically tailored for healthcare? Not a general-purpose AI that might help with everything from writing poetry to recommending sushi restaurants, but a tool that actually understands the unique complexity of medicine. Both founders come from families steeped in medical professions and both have seen first-hand what happens when healthcare systems are stretched too thin. Since 2017, they've been developing models trained on real-world medical conversations. When the COVID-19 pandemic hit, the world may have ground to a halt, but for Corti, it was rocket-fuel. Their voice-based AI models quickly became more accurate, more responsive and – crucially - more trusted. Corti isn't trying to replace doctors. It's trying to make every doctor faster, more informed and more precise. The Scalpel, Not the Swiss Army Knife Now, let's talk about scale. While the big boys - OpenAI, Gemini, StabilityAI etc. - are busy building multi-purpose Swiss Army knives, Corti is building a scalpel. In healthcare, 98% accuracy isn't good enough. You don't want a chatbot guessing whether you're having a heart attack or just heartburn. You want a system trained specifically to know the difference. That's the genius of Corti. It doesn't pretend to be everything to everyone. It focuses on clinical use cases, where the final 1-2% in accuracy can mean the difference between life and death. And unlike general models, Corti's systems can reuse global medical condition data in ways that scale intelligently across borders. What's learned in a hospital in Detroit can benefit a clinic in Dakar. Corti's API Strategy: If You Build It (Right), They Will Come Initially, Corti sold products that were built on its foundational model directly to healthcare stakeholders like hospitals, universities, clinics etc. Turns out, that's like trying to sell a Formula 1 engine to someone who just wants a reliable bicycle. The buyers weren't quite ready. So Corti did what smart start-ups do: it pivoted. In 2025, it launched an API layer that allows existing healthcare software providers to integrate Corti's specialised AI seamlessly, specialised APIs to software developers rather than an app to the end user. The idea? Don't change the tools that doctors and nurses already know - just supercharge them. Since launch, there's now a waiting list to onboard Corti's API solution. It turns out the world doesn't just want better AI in healthcare. It needs it. The model delivers real-time feedback, improves efficiency and enhances accuracy. In other words, it lets medical professionals do what they do best - but faster, with fewer mistakes and more time for patients. Imagine a world where you get the right diagnosis, first time. That's not science fiction. That's Corti. Global Mission, Danish Roots Corti's rise is more than just a start-up success story. It's a lesson in how you can build capital-efficient, highly specialised AI platforms without raising billions of dollars or relocating to the Bay Area. That should be music to the ears to European founders or any founder who's been told they need a 10,000-square-foot office and a rocket launchpad to be taken seriously. It's also a tribute to Denmark's tech ecosystem. This is a country that supports deep tech innovation, educates top talent and thinks globally from day one. Whether it's exporting bacon, wind turbines or language models, Denmark knows how to scale. The Bottom Line We're facing a global healthcare crisis. Doctors are burning out, systems are creaking and patients are suffering. But from the quiet streets of Copenhagen, a start-up is showing the world what's possible when you combine technical rigour, clinical empathy and a laser-focused mission. Corti may not be a household name yet, but in the world of healthcare AI, it is already making waves. And if you are wondering where the next big leap in med-tech will come from, don't be surprised if it comes from the country that produced Lego and Bang & Olufsen. So, to all the founders and investors out there looking for the next frontier: Look north. Denmark isn't just ready for the challenge - it's already building the solution.
Yahoo
10-03-2025
- Science
- Yahoo
Scientists Think Light May Hold the Memory of Ancient Cataclysms
According to Einstein's theory of general relativity, gravitational waves warp spacetime. In the process, they could imprint permanent changes, or 'gravitational memory,' on their surroundings. Researchers now think that gravitational memory could be written on photons all over the cosmic microwave background—the oldest radiation in the universe. Though gravitational memory is thought to be too subtle to be detected even by our most sensitive equipment, upcoming instruments might finally be able to pick up on a signal. If two black holes crashed into each other billions of years ago, even though we weren't around to observe, could we find out? Well, as it turns out, maybe we could. Einstein's theory of general relativity describe how the gravity of massive objects and extreme phenomena—such as black hole mergers and core-collapse supernovae (which sometimes end up as black holes)—causes ripples that permanently warp spacetime and traverse the void at the speed of light. These ripples are known as gravitational waves, and the effects of these waves thought to be permanently imprinted on their surroundings as 'gravitational memory.' Evidence of gravitational memory, however, continues to elude telescopes. Even the Laser Interferometer Gravitational Wave Observatory (LIGO)—which first detected gravitational waves in 2015—has not been able to pick up a memory signal. Fast-forward a decade, and a team of researchers from the Niels Bohr Institute in Denmark and the University of Valencia in Spain now have an idea of where we could search to finally find these mysterious gravitational memory imprints, which they described in a study uploaded to the preprint server arXiv. Cataclysmic events leave their mark on the cosmic microwave background (CMB)—the remnant of the immense shockwave sent through space by the Big Bang and the oldest detectable radiation in the universe. The researchers behind this new paper think that the CMB is probably embedded with 'memories' of black hole mergers as a result of the gravitational waves that resulted from those mergers leaving behind temperature changes in CMB radiation. 'Photons traveling through space may experience permanent distortions and deflection caused by the gravitational wave memory from one such merger event,' the team said in the paper. '[There is] a resulting change in photon wavelength.' Gravitational waves interacting with particles of light, or photons, can shift their direction, velocity, or angular momentum. As a result, photons affected by those permanent changes are essentially taking gravitational memory with them as they travel. If we were to somehow detect the changes made to the photons, we could analyze these effects and find out what kinds of events caused them. Gravitational memory could reveal such things as distances to merging black holes, masses, and the forces of collisions. It could also illuminate more about how the early universe evolved. In the case of a core-collapse supernova, the death of a massive star that has burned all its energy and collapses in a violent explosion, gravitational memory could give us insight into properties no telescope or spacecraft can observe. Because oscillations of waves from gravitational memory are predicted to have much smaller amplitudes than the gravitational waves they come from—never mind the additional noise from human activity on Earth—they have not yet been detected. Even the most hypersensitive equipment is still not sensitive enough. NASA's upcoming LISA (Laser Interferometer Space Antenna) observatory might be our best shot at finding evidence. 'Though hidden below a myriad of other signals,' the researchers wrote, 'the entire merger history of black holes is marked on [the CMB, which is] the oldest image of our universe.' You Might Also Like The Do's and Don'ts of Using Painter's Tape The Best Portable BBQ Grills for Cooking Anywhere Can a Smart Watch Prolong Your Life?
