Latest news with #EHT
NDTV
2 days ago
- Science
- NDTV
Is Our Black Hole Defying Physics? New AI Study Challenges Theories
Astronomers, using AI and high-throughput computing from the University of Wisconsin-Madison's CHTC, have unlocked new insights into Sagittarius A* - the supermassive black hole at the heart of our galaxy. By training a neural network on millions of simulations, researchers found the black hole is spinning near its maximum speed, with its axis of rotation aimed toward Earth. The findings are based on data from the Event Horizon Telescope and offer fresh understanding of black hole behaviour. The AI also suggests that the emission near the black hole is primarily from extremely hot electrons in the accretion disk rather than a jet, and that the magnetic fields in the disk behave differently than previously thought. This research, published in Astronomy & Astrophysics, was made possible by high-throughput computing, a distributed computing method pioneered by Miron Livny, which allowed researchers to process a massive amount of data efficiently. "That we are defying the prevailing theory is, of course, exciting," says lead researcher Michael Janssen, of Radboud University Nijmegen, the Netherlands. "However, I see our AI and machine learning approach primarily as a first step. Next, we will improve and extend the associated models and simulations." "The ability to scale up to the millions of synthetic data files required to train the model is an impressive achievement," adds Chi-kwan Chan, an Associate Astronomer of Steward Observatory at the University of Arizona and a longtime PATh collaborator. "It requires dependable workflow automation and effective workload distribution across storage resources and processing capacity." "We are pleased to see EHT leveraging our throughput computing capabilities to bring the power of AI to their science," says Professor Anthony Gitter, a Morgridge Investigator and a PATh Co-PI. "Like in the case of other science domains, CHTC's capabilities allowed EHT researchers to assemble the quantity and quality of AI-ready data needed to train effective models that facilitate scientific discovery." The NSF-funded Open Science Pool, operated by PATh, offers computing capacity contributed by more than 80 institutions across the United States. The Event Horizon black hole project performed more than 12 million computing jobs in the past three years. "A workload that consists of millions of simulations is a perfect match for our throughput-oriented capabilities that were developed and refined over four decades", says Livny, director of the CHTC and lead investigator of PATh. "We love to collaborate with researchers who have workloads that challenge the scalability of our services."
Japan Forward
2 days ago
- Science
- Japan Forward
Black Holes: What They Are and What They're Not
このページを 日本語 で読む Almost everyone has heard the term "black hole" — it's one of the most recognizable concepts in modern science. But with that familiarity comes a lot of misunderstanding. While some misconceptions are too technical to unpack without advanced knowledge, this article focuses on several common ones about black holes that can be explained relatively clearly. People often describe a black hole as "a hole in space-time." Even experts sometimes use this phrase, but it's just a metaphor. In reality, a black hole has a surprisingly simple structure. It consists of only two parts: the singularity, where all the black hole's mass is compressed into a single point, and the event horizon that surrounds it. The event horizon isn't a physical substance like a membrane or mist. No matter how closely you look, there's nothing that resembles a surface. A black hole isn't literally a hole or a vortex, and it's not a traditional celestial object. It's better understood as a region of space-time with extreme properties. One of the most striking features is that beyond the event horizon, space behaves like time. It "flows" only inward toward the singularity, just as time only moves forward for us. This one-way flow is what gives the black hole its "hole-like" reputation. So, the metaphor of a "hole in space-time" likely comes from this defining feature: a region of severely distorted space-time from which nothing can return. If "observing a black hole" means directly detecting radiation from the singularity or the event horizon, then this idea is mostly correct. Hawking radiation, the thermodynamic radiation of black holes, is too weak to be detected for the foreseeable future, so it can be ignored in this discussion. In practice, though, observing a black hole usually means finding evidence of its presence through indirect methods. In that sense, there are several reliable ways to do it. The most common method is to observe electromagnetic radiation, such as strong X-rays or radio waves. The black hole itself does not emit radiation, but it pulls in a large amount of matter, usually gas or dust. As the material spirals inward, it heats up due to friction and compression, producing intense radiation. While other cosmic objects can also emit radiation, the extreme brightness and compactness of the source often point to a black hole. In the case of supermassive black holes, we can even map the surrounding radiation in enough detail to image the black hole's "shadow." The first image of this kind was captured by the Event Horizon Telescope (EHT), a global network of radio observatories. In April 2017, the EHT imaged the supermassive black hole at the center of the galaxy M87 in the Virgo constellation. The image was released to the public on April 10, 2019. To observe a black hole this way, there must be nearby matter to interact with. But since space is mostly empty, black holes with visible material around them are relatively rare. That's why many remain hidden from direct observation. Fortunately, newer indirect methods have made it possible to detect more of these hidden black holes. One is gravitational lensing, where a black hole bends the light from more distant stars. Another is the detection of gravitational waves, which are ripples in space-time produced when black holes collide. These techniques have opened exciting new paths in astrophysics, helping scientists better understand black holes and the structure of the universe. The idea that black holes are dangerous probably comes mainly from science fiction. However, in reality, black holes don't indiscriminately suck in or tear apart everything nearby. It's true that black holes have incredibly strong gravity, but that's mainly because their mass is packed into an extremely small space. In fact, their compactness allows matter, and even light, to get much closer to the center than with other objects of the same mass. Stars or planets have physical surfaces or atmospheres that prevent such close approach. (©Sankei) In fact, if the Sun were suddenly replaced by a black hole of the same mass, Earth and the other planets would continue orbiting just as they do now. We'd lose sunlight, which would be catastrophic for life, but Earth wouldn't be pulled in or torn apart. Whether something falls into a black hole depends on how close it is and whether it can change its speed or direction. As long as it stays outside the event horizon — the point of no return — it can still escape. That's why we can observe light and matter swirling just outside black holes. There's also a common idea that anything near a black hole gets stretched and ripped apart, a process nicknamed "spaghettification." This effect is real, but it mostly applies to smaller black holes. In those cases, tidal forces — differences in gravity across an object — become extreme just a few hundred kilometers from the center. A person or spacecraft getting too close would be torn apart long before reaching the event horizon. However, for supermassive black holes, which are millions of times the mass of the Sun, you wouldn't be torn apart or feel any discomfort even near the event horizon. In fact, you might not notice anything unusual at all as you cross that boundary. The reason for this big difference lies in the gravitational field around the black hole. For ordinary celestial bodies ike Earth, the difference in gravity over such a small distance is too weak to notice. In fact, even over a small distance, like from your toes to your head, there is a slight difference in gravitational strength. But near a black hole, where gravity grows stronger the closer you get to the center, the more significant this difference becomes. The varying strength of gravitational pull across an object can become so extreme that it stretches and tears the object apart. Again, the distance from the black hole at which these extreme forces occur depends on the black hole's mass. (©Laura A Whitlock, Kara C Granger & Jane D Mahon) The distance from the singularity to the event horizon, called the Schwarzschild radius, is also determined by the black hole's mass. The Schwarzschild radius grows much more rapidly than the distance at which extreme tidal forces begin to emerge. Because of this difference, the larger the black hole, the safer it is to approach — up to a point. Once you cross the event horizon, there's no coming back. And the deeper you go, the stronger the tidal forces become. Eventually, even in a supermassive black hole, those forces would tear you apart before you reached the center. Larger objects like stars don't fare any better. Even supermassive black holes can shred them before they reach the event horizon. So, if you're planning a trip near a black hole, leave the stars behind — and whatever you do, don't fall in. Because black holes are often described as objects in space, it's easy to picture them having a solid, dark surface. But as explained earlier, a black hole isn't really a celestial object. It's more accurate to think of it as a region of space-time with extreme properties. As mentioned before, you can actually get quite close to a large black hole without immediately being affected. But even up close, you wouldn't see a wall, a membrane, or a swirl of darkness. The event horizon — the point of no return — has no visible surface and gives no physical warning. If you crossed it, you wouldn't feel anything special. No bump, no jolt, no sudden shift. In fact, you might not realize you've passed it at all. But once you do, escape becomes impossible. You'd be on a one-way path toward the singularity. If black hole tourism ever becomes a thing, it's safe to assume there'd be clear warnings posted: "Do Not Enter: Black Hole Ahead ." The gravity would already be distorting your view of space around you, but without a visible marker, you wouldn't be able to tell where the event horizon actually is. The rumor that particle accelerators could create black holes and destroy the Earth began during the construction of CERN's Large Hadron Collider (LHC). The idea even shows up in some science fiction stories, so you may have heard it before. But given that Earth is still intact, we can safely say this fear is unfounded. A particle accelerator at CERN. (©Maximilien Brice) The concern arose because the LHC is capable of producing particle collisions at extremely high energies. Furthermore, some theoretical models also propose the existence of "extra dimensions" beyond the four we experience. If these extra dimensions exist and are larger than expected, it's theoretically possible — though extremely unlikely — that tiny black holes could form in these collisions. Furthermore, this scenario depends on several optimistic assumptions. First, we don't yet know if extra dimensions exist. And even if they do, the conditions needed to produce black holes are probably not met by the LHC. More importantly, if the LHC could create black holes, nature would already have done so. That's because cosmic rays, which are high-energy particles from space, routinely strike Earth's atmosphere with far more energy than the LHC can generate. These natural particle collisions have been happening for 4.6 billion years, all over the planet. If high-energy collisions could destroy Earth, it would have happened long ago. Even in the unlikely event that the LHC did create a tiny black hole, it wouldn't be dangerous. According to theory, it would vanish almost instantly due to a process called Hawking radiation. Even if Hawking radiation turned out not to occur, any black hole produced would be traveling so fast that it would escape Earth's gravity and fly off into space. And if, against all odds, such a black hole somehow stayed trapped by Earth's gravity, it would be smaller than an atom and would absorb almost nothing as it orbited through the planet. By the time it finally settled at Earth's core, millions or billions of years later, the Sun would have reached the end of its life, likely engulfing or incinerating the Earth long before any black hole could do serious harm. NASA Science Editorial Team. （Aug 13, 2019） "Shedding Light on Black Holes". NASA Sara Rigby. （Mar 30, 2021） "7 black hole 'facts' that aren't true". BBC Science Focus. Amanda Bauer & Christopher A Onken. "Black hole truths, myths and mysteries." Australian Academy of Science. Author: The Sankei Shimbun このページを 日本語 で読む
WIRED
11-06-2025
- Science
- WIRED
Artificial Intelligence Is Unlocking the Secrets of Black Holes
Jun 11, 2025 5:30 AM A neural network trained with simulations of supermassive black holes has found that the one at the center of the Milky Way, Sagittarius A*, likely rotates at maximum speed. An artistic impression of a neural network connecting observations of black holes (left) with models of them (right). Photograph: EHT/Janssen et al. There may not yet be telescopes capable of unlocking all the secrets of supermassive black holes, but AI is now on the case. Recently, an international team of astronomers successfully trained a neural network with millions of black hole simulations to allow it to interpret fuzzy data captured from these enigmatic space objects in real life. Of the various methods for investigating a black hole, the Event Horizon Telescope is the most famous. The EHT isn't a single instrument but rather a number of radio telescopes around the world that work together like a single telescope. Thanks to the EHT, it's been possible to obtain images of the supermassive black holes M87 and Sagittarius A*. These are not images in the traditional sense but instead are visualizations of radio waves coming from the black holes. To create these images, supercomputers in different parts of the world processed the radio signals captured by the EHT. But in the process, they discarded much of the information gathered, as it was difficult to interpret. The new neural network, trained by experts at the Morgridge Research Institute in Wisconsin, aims to tap into that sea of data to improve the resolution of the EHT's readings and make new discoveries. According to a press release from the institute, the artificial intelligence successfully analyzed the once-discarded information and established new parameters of Sagittarius A*, which sits at the center of the Milky Way. An alternative image of the black hole's structure was generated, with this revealing some new characteristics of the black hole. 'Researchers now suspect that the black hole at the center of the Milky Way is spinning at almost top speed,' wrote the researchers in a press release. The new image also also indicates that the black hole's rotation axis points to the Earth and gives clues as to the causes and characteristics of the disks of material that circulate around the black hole. Astronomers had previously estimated that Sagittarius A* rotates at a moderate to fast speed. Knowing its actual rotational speed is important, since it allows us to infer how the radiation around the black hole behaves and provides clues about its stability. 'That we are defying the prevailing theory is of course exciting,' lead researcher Michael Janssen, of Radboud University Nijmegen in the Netherlands, said in the press release. 'However, I see our AI and machine learning approach primarily as a first step. Next, we will improve and extend the associated models and simulations.' This story originally appeared on WIRED en Español and has been translated from Spanish.
Yahoo
29-04-2025
- Business
- Yahoo
Honolulu Council to review empty-homes tax study
A proposed Honolulu City Council measure to penalize real-property owners who leave their Oahu residences vacant for extended periods of time has a chance to start moving again following the release of the first phase of a city-commissioned study. Bill 46, which was introduced in August by Council Chair Tommy Waters and Council member Radiant Cordero, was formally deferred in December following blistering public testimony against the empty- homes tax measure. The third reading of the bill also was temporarily postponed pending completion of a study from Ernst &Young LLP, which the city paid nearly $500, 000 to assess the implications of an EHT. The Council's Budget Committee at 9 a.m. today is expected to receive an informational briefing on the Ernst &Young third-party feasibility report, which was released April 21, and makes recommendations for the first phase of a two-phase plan for the empty-homes tax. But a study is not all that is needed to advance Bill 46. It's going to take votes, too, and it's still unclear whether the measure will get enough Council support to begin moving again. Before the Council's Dec. 11 vote to defer the measure, four on the nine-member Council—Esther Kia 'aina, Val Oki moto, Augie Tulba and Andria Tupola—indicated they would not support the bill in its current form, a floor draft. Waters told the Honolulu Star-Advertiser's editorial board during a Zoom meeting Thursday, 'I'm hoping that through the questions and answers, and possibly amending the bill to get that fifth vote. Right now I don't even know if we're even close to getting a fifth vote. I sure hope so.' Don 't miss out on what 's happening ! Stay in touch with breaking news, as it happens, conveniently in your email inbox. It 's FREE ! Email 28141 Sign Up By clicking to sign up, you agree to Star-Advertiser 's and Google 's and. This form is protected by reCAPTCHA. Waters said he is unsure how Scott Nishimoto, the newest Council member, would vote. If Bill 46 moves forward as drafted, it would ensure residential properties are used as actual homes instead of investments—particularly by those who might live outside the state, whether on the mainland or in a foreign country. As drafted, the measure would tax vacant real property by as much as 3 %. That means a home valued at $1 million could receive a $30, 000 tax bill each year that it remains empty. The draft version would levy, assess and collect an EHT for each tax year—from July 1 to June 30—for every parcel on which an empty home is situated. Bill 46 as drafted also would introduce a new Residential E tax classification in Honolulu. As proposed, at least 20 % of the revenues from the Residential E classification will be directed to affordable-housing programs overseen by the city's Office of Housing. The remaining funds will support various housing-related issues, including homelessness, cost-of-living increases, rental stability and existing city services, and cover the tax administration costs, Council staff stated. The effective date for Residential E classification was set for tax years beginning July 1, 2027. Waters said for him the main reason to support Bill 46 is to address home shortages by getting 'owners of these empty homes to convert to a rental property or to sell it.' He said the Department of Business, Economic Development and Tourism asserts a 25, 000-home shortage, and said it would go a long way 'if we could convert most of these to rentals to help deal with that shortage.' But Waters noted that the city-commissioned study determined 'the estimate of conversion (to rentals ) is much lower than we were hoping for.' 'They're estimating that they're only going to convert 1, 000 to 2, 000 units, ' he said. 'Even 1, 000 to 2, 000 units is great, but I was hoping that it would be a lot more.' He said estimates from the city-commissioned study are low due to existing exemptions within Bill 46, including properties with a homeowner's exemption whereby such owners would be eligible for an additional exemption to the EHT for a second property. 'That's part of the problem, ' Waters asserted. 'So we've got to look at possibly amending that.' Waters said the city-commissioned study also differs from a prior University of Hawaii Economic Research Organization report that determined there were about 18, 000 possible vacant homes on Oahu. '(Ernst &Young ) did their study based on water usage, ' he related. 'They said if you use 50 gallons or less, it's likely you're empty.' Due to this, Waters said the city's study 'revised ' the numbers, to say 'we're probably only looking at anywhere from 7, 316 to 11, 184 properties that would fall into this category—which is a lot less than we thought.' Since its introduction, Bill 46 has drawn mixed reaction from the community. Ross Isokane, who is part of a grassroots coalition of residents in support of Bill 46, told the Star-Advertiser that passage of an EHT will benefit Oahu. 'Our impossibly unaffordable housing crisis has been getting worse, not better, ' said Isokane, who is also a member of the Downtown-Chinatown Neighborhood Board. 'While building more housing is certainly a necessary step, outside speculative investment diverts our efforts to increase housing supply for local residents.' Isokane opined that Bill 46 is the 'only piece of legislation alive today at the city or state level that will help mitigate outside speculative investment on Oahu.' But most who spoke on Bill 46 at the Council's December meeting opposed its passage. William Deeb, a Kailua homeowner, said the measure is not about housing, 'it's about revenue generation ' for the city. Ted Kefalas, with the Grassroot Institute of Hawaii, noted there are not any tax rates in Bill 46, a real-property tax measure.
Press and Journal
23-04-2025
- Business
- Press and Journal
New report warns Scotland is 'sleepwalking' towards crofting catastrophe
Policy changes and investment are badly needed to avoid Scotland 'sleepwalking' into an economic clearance of crofting areas, a new report warns. Cultivating Change: Crofting on Eigg is published today. It is billed as an in-depth analysis of opportunities for the growth and development of crofting on Eigg, one of the Small Isles of the Inner Hebrides. Eigg is the second largest of the Small Isles after Rum and home to just over 100 people. It is owned by Isle of Eigg Heritage Trust (EHT), which has managed it since a community buyout in 1997. Today's EHT report looks at how crofting has evolved in recent years. It also highlights the challenges faced by the island's crofting community. And it explores how community ownership can strengthen and grow crofting. But there's a grim warning too, with EHT saying: 'Without policy changes and investment, we could be sleepwalking into the economic clearance of the crofting areas.' The trust calls for 'investment in the infrastructure that crofting needs', such as housing, transport and access to markets. It also wants to see reforms to agricultural funding to support small-scale food producers. And it highlights a lack of small-scale abattoir provision locally. EHT adds: 'Crofting is a viable business that can attract young people to stay, return or move to Eigg. 'This vision includes a mix of businesses, with sustainable food production at its core. 'It is a vision where all crofts are being used, where each croft retains its independence, but where there are more opportunities for working in community. 'And it is one where the whole township manages the land sustainably to ensure it remains both productive and supports biodiversity. 'It is hoped that this report will inform policy discussions and inspire further support for small-scale, sustainable land use across the Highlands and Islands.' Speaking ahead of today's launch, report author Ed Pybus, of Crow Consulting, said: 'This project and report began when Isle of Eigg Heritage Trust wanted to look at how best to support crofting on Eigg. 'From the initial meeting onwards, crofters have led this project. I have tried to distill down six months of conversation, research and observations. 'It has become clear the challenges faced by crofters on Eigg are also seen across crofting communities in Scotland. 'These challenges are numerous, interconnected and pose risks to the full realisation of the benefits of crofting for communities. 'At worst, they could lead to the gradual disappearance of crofting.' Mr Pybus added: 'Crofting should not be viewed as a fringe activity but as a central part of Scotland's strategy to achieve a just transition, become a 'good food nation', retain rural populations, and build community wealth and a wellbeing economy.' EHT chairwoman Ailsa Raeburn said: 'This report tells an important part of Eigg's story and highlights the vital role crofting has played in shaping the island's past, present, and future. 'It aims to deepen understanding of crofting's significance and its continued relevance. 'Rather than being a final word, the report marks a step on the way to growing and strengthening crofting on Eigg.' The full report is available online from and
