How will the universe end? A changing understanding of dark energy may provide a new answer
NEW YORK (AP) — Scientists are homing in on the nature of a mysterious force called dark energy, and nothing short of the fate of the universe hangs in the balance.
The force is enormous — it makes up nearly 70% of the universe. And it is powerful — it is pushing all the stars and galaxies away from each other at an ever faster rate.
And now scientists are getting a little closer to understanding how it behaves. The big question is whether this dark energy is a constant force, which scientists have long thought, or whether the force is weakening, a surprising wrinkle tentatively proposed last year.
Results presented at a meeting of the American Physical Society Wednesday bolster the case that the force is weakening, though scientists are not yet certain and they still haven't worked out what this means for the rest of their understanding of the universe.
The updated findings come from an international research collaboration that is creating a three-dimensional map to see how galaxies have spread and clustered over 11 billion years of the universe's history. Carefully tracking how galaxies move helps scientists learn about the forces that are moving them around.
Called the Dark Energy Spectroscopic Instrument, the collaboration released its first analysis of 6 million galaxies and quasars last year and has now added more data, bringing the count to nearly 15 million. Their updated results, taken with other measurements — exploding stars, leftover light from the young universe and distortions in galaxy shape — support the idea presented last year that dark energy may be waning.
'It's moving from a really surprising finding to almost a moment where we have to throw out how we've thought about cosmology and start over,' said Bhuvnesh Jain, a cosmologist with the University of Pennsylvania who was not involved with the research.
It's not time to completely rule out the idea that dark energy is constant because the new results are still shy of the gold standard level of statistical proof physics requires. The collaboration aims to map around 50 million galaxies and quasars by the end of its survey in 2026. And other efforts around the globe have an eye on dark energy and aim to release their own data in the coming years, including the European Space Agency's Euclid mission and the Vera C. Rubin Observatory in Chile.
'We want to see several different collaborations having similar measurements' at that gold standard to be sure that dark energy is weakening, said cosmologist Kris Pardo with the University of Southern California who was not involved with the new research.
If dark energy is constant, scientists say our universe may continue to expand forever, growing ever colder, lonelier and still.
If dark energy ebbs with time, which now seems plausible, the universe could one day stop expanding and then eventually collapse on itself in what's called the Big Crunch. It might not seem like the cheeriest fate, but it offers some closure, said cosmologist and study collaborator Mustapha Ishak-Boushaki of the University of Texas at Dallas.
'Now, there is the possibility that everything comes to an end,' he said. 'Would we consider that a good or bad thing? I don't know.'
—-
The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute's Science and Educational Media Group and the Robert Wood Johnson Foundation. The AP is solely responsible for all content.
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San Francisco Chronicle
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AI chatbots need more books to learn from. These libraries are opening their stacks
CAMBRIDGE, Mass. (AP) — Everything ever said on the internet was just the start of teaching artificial intelligence about humanity. Tech companies are now tapping into an older repository of knowledge: the library stacks. Nearly one million books published as early as the 15th century — and in 254 languages — are part of a Harvard University collection being released to AI researchers Thursday. Also coming soon are troves of old newspapers and government documents held by Boston's public library. Cracking open the vaults to centuries-old tomes could be a data bonanza for tech companies battling lawsuits from living novelists, visual artistsand others whose creative works have been scooped up without their consent to train AI chatbots. 'It is a prudent decision to start with public domain data because that's less controversial right now than content that's still under copyright,' said Burton Davis, a deputy general counsel at Microsoft. Davis said libraries also hold 'significant amounts of interesting cultural, historical and language data' that's missing from the past few decades of online commentary that AI chatbots have mostly learned from. Supported by 'unrestricted gifts' from Microsoft and ChatGPT maker OpenAI, the Harvard-based Institutional Data Initiative is working with libraries around the world on how to make their historic collections AI-ready in a way that also benefits libraries and the communities they serve. 'We're trying to move some of the power from this current AI moment back to these institutions,' said Aristana Scourtas, who manages research at Harvard Law School's Library Innovation Lab. 'Librarians have always been the stewards of data and the stewards of information.' Harvard's newly released dataset, Institutional Books 1.0, contains more than 394 million scanned pages of paper. 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Before ChatGPT sparked a commercial AI frenzy, most AI researchers didn't think much about the provenance of the passages of text they pulled from Wikipedia, from social media forums like Reddit and sometimes from deep repositories of pirated books. They just needed lots of what computer scientists call tokens — units of data, each of which can represent a piece of a word. Harvard's new AI training collection has an estimated 242 billion tokens, an amount that's hard for humans to fathom but it's still just a drop of what's being fed into the most advanced AI systems. Facebook parent company Meta, for instance, has said the latest version of its AI large language model was trained on more than 30 trillion tokens pulled from text, images and videos. Meta is also battling a lawsuit from comedian Sarah Silverman and other published authors who accuse the company of stealing their books from 'shadow libraries' of pirated works. Now, with some reservations, the real libraries are standing up. OpenAI, which is also fighting a string of copyright lawsuits, donated $50 million this year to a group of research institutions including Oxford University's 400-year-old Bodleian Library, which is digitizing rare texts and using AI to help transcribe them. When the company first reached out to the Boston Public Library, one of the biggest in the U.S., the library made clear that any information it digitized would be for everyone, said Jessica Chapel, its chief of digital and online services. 'OpenAI had this interest in massive amounts of training data. We have an interest in massive amounts of digital objects. So this is kind of just a case that things are aligning,' Chapel said. Digitization is expensive. It's been painstaking work, for instance, for Boston's library to scan and curate dozens of New England's French-language newspapers that were widely read in the late 19th and early 20th century by Canadian immigrant communities from Quebec. Now that such text is of use as training data, it helps bankroll projects that librarians want to do anyway. 'We've been very clear that, 'Hey, we're a public library,'" Chapel said. 'Our collections are held for public use, and anything we digitized as part of this project will be made public.' Harvard's collection was already digitized starting in 2006 for another tech giant, Google, in its controversial project to create a searchable online library of more than 20 million books. Google spent years beating back legal challenges from authors to its online book library, which included many newer and copyrighted works. 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Yahoo
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AI chatbots need more books to learn from. These libraries are opening their stacks
CAMBRIDGE, Mass. (AP) — Everything ever said on the internet was just the start of teaching artificial intelligence about humanity. Tech companies are now tapping into an older repository of knowledge: the library stacks. Nearly one million books published as early as the 15th century — and in 254 languages — are part of a Harvard University collection being released to AI researchers Thursday. Also coming soon are troves of old newspapers and government documents held by Boston's public library. Cracking open the vaults to centuries-old tomes could be a data bonanza for tech companies battling lawsuits from living novelists, visual artistsand others whose creative works have been scooped up without their consent to train AI chatbots. 'It is a prudent decision to start with public domain data because that's less controversial right now than content that's still under copyright,' said Burton Davis, a deputy general counsel at Microsoft. Davis said libraries also hold 'significant amounts of interesting cultural, historical and language data' that's missing from the past few decades of online commentary that AI chatbots have mostly learned from. Supported by 'unrestricted gifts' from Microsoft and ChatGPT maker OpenAI, the Harvard-based Institutional Data Initiative is working with libraries around the world on how to make their historic collections AI-ready in a way that also benefits libraries and the communities they serve. 'We're trying to move some of the power from this current AI moment back to these institutions,' said Aristana Scourtas, who manages research at Harvard Law School's Library Innovation Lab. 'Librarians have always been the stewards of data and the stewards of information.' Harvard's newly released dataset, Institutional Books 1.0, contains more than 394 million scanned pages of paper. One of the earlier works is from the 1400s — a Korean painter's handwritten thoughts about cultivating flowers and trees. The largest concentration of works is from the 19th century, on subjects such as literature, philosophy, law and agriculture, all of it meticulously preserved and organized by generations of librarians. It promises to be a boon for AI developers trying to improve the accuracy and reliability of their systems. 'A lot of the data that's been used in AI training has not come from original sources,' said the data initiative's executive director, Greg Leppert, who is also chief technologist at Harvard's Berkman Klein Center for Internet & Society. This book collection goes "all the way back to the physical copy that was scanned by the institutions that actually collected those items,' he said. Before ChatGPT sparked a commercial AI frenzy, most AI researchers didn't think much about the provenance of the passages of text they pulled from Wikipedia, from social media forums like Reddit and sometimes from deep repositories of pirated books. They just needed lots of what computer scientists call tokens — units of data, each of which can represent a piece of a word. Harvard's new AI training collection has an estimated 242 billion tokens, an amount that's hard for humans to fathom but it's still just a drop of what's being fed into the most advanced AI systems. Facebook parent company Meta, for instance, has said the latest version of its AI large language model was trained on more than 30 trillion tokens pulled from text, images and videos. Meta is also battling a lawsuit from comedian Sarah Silverman and other published authors who accuse the company of stealing their books from 'shadow libraries' of pirated works. Now, with some reservations, the real libraries are standing up. OpenAI, which is also fighting a string of copyright lawsuits, donated $50 million this year to a group of research institutions including Oxford University's 400-year-old Bodleian Library, which is digitizing rare texts and using AI to help transcribe them. When the company first reached out to the Boston Public Library, one of the biggest in the U.S., the library made clear that any information it digitized would be for everyone, said Jessica Chapel, its chief of digital and online services. 'OpenAI had this interest in massive amounts of training data. We have an interest in massive amounts of digital objects. So this is kind of just a case that things are aligning,' Chapel said. Digitization is expensive. It's been painstaking work, for instance, for Boston's library to scan and curate dozens of New England's French-language newspapers that were widely read in the late 19th and early 20th century by Canadian immigrant communities from Quebec. Now that such text is of use as training data, it helps bankroll projects that librarians want to do anyway. 'We've been very clear that, 'Hey, we're a public library,'" Chapel said. 'Our collections are held for public use, and anything we digitized as part of this project will be made public.' Harvard's collection was already digitized starting in 2006 for another tech giant, Google, in its controversial project to create a searchable online library of more than 20 million books. Google spent years beating back legal challenges from authors to its online book library, which included many newer and copyrighted works. It was finally settled in 2016 when the U.S. Supreme Court let stand lower court rulings that rejected copyright infringement claims. Now, for the first time, Google has worked with Harvard to retrieve public domain volumes from Google Books and clear the way for their release to AI developers. Copyright protections in the U.S. typically last for 95 years, and longer for sound recordings. How useful all of this will be for the next generation of AI tools remains to be seen as the data gets shared Thursday on the Hugging Face platform, which hosts datasets and open-source AI models that anyone can download. The book collection is more linguistically diverse than typical AI data sources. Fewer than half the volumes are in English, though European languages still dominate, particularly German, French, Italian, Spanish and Latin. A book collection steeped in 19th century thought could also be 'immensely critical' for the tech industry's efforts to build AI agents that can plan and reason as well as humans, Leppert said. 'At a university, you have a lot of pedagogy around what it means to reason,' Leppert said. 'You have a lot of scientific information about how to run processes and how to run analyses.' At the same time, there's also plenty of outdated data, from debunked scientific and medical theories to racist narratives. 'When you're dealing with such a large data set, there are some tricky issues around harmful content and language," said Kristi Mukk, a coordinator at Harvard's Library Innovation Lab who said the initiative is trying to provide guidance about mitigating the risks of using the data, to 'help them make their own informed decisions and use AI responsibly.' ———— The Associated Press and OpenAI have a licensing and technology agreement that allows OpenAI access to part of AP's text archives.
San Francisco Chronicle
a day ago
- San Francisco Chronicle
Solstices brought Mayan communities together, using monuments shaped by science and religion – and kingly ambitions, too
Eds: This story was supplied by The Conversation for AP customers. The Associated Press does not guarantee the content. Gerardo Aldana, University of California, Santa Barbara (THE CONVERSATION) K'ahk' Uti' Witz' K'awiil knew his history. For 11 generations, the Mayan ruler's dynasty had ruled Copan, a city-state near today's border between Honduras and Guatemala. From the fifth century C.E. into the seventh century, scribes painted his ancestors' genealogies into manuscripts and carved them in stone monuments throughout the city. Around 650, one particular piece of architectural history appears to have caught his eye. Centuries before, village masons built special structures for public ceremonies to view the Sun – ceremonies that were temporally anchored to the solstices, like the one that will occur June 20, 2025. Building these types of architectural complexes, which archaeologists call 'E-Groups,' had largely fallen out of fashion by K'ahk' Uti' Witz' K'awiil's time. But aiming to realize his ambitious plans for his city, he seems to have found inspiration in these astronomical public spaces, as I've written about in my research on ancient Mayan hieroglyphically recorded astronomy. K'ahk' Uti' Witz' K'awiil's innovations are a reminder that science changes through discovery or invention – but also occasionally for personal or political purposes, particularly in the ancient world. E-Groups were first constructed in the Mayan region as early as 1000 B.C.E. The site of Ceibal, on the banks of the Pasión River in central Guatemala, is one such example. There, residents built a long, plastered platform bordering the eastern edge of a large plaza. Three structures were arranged along a north-south axis atop this platform, with roofs tall enough to rise above the rainforest floral canopy. Within the center of the plaza, to the west of the platform, they built a radially symmetric pyramid. From there, observers could follow sunrise behind and between the structures on the platform over the course of the year. At one level, the earliest E-Group complexes served very practical purposes. In Preclassic villages where these complexes have been found, like Ceibal, populations of several hundred to a few thousand lived on 'milpa' or 'slash-and-burn' farming techniques practices still maintained in pueblos throughout Mesoamerica today. Farmers chop down brush vegetation, then burn it to fertilize the soil. This requires careful attention to the rainy season, which was tracked in ancient times by following the position of the rising Sun at the horizon. Most of the sites in the Classic Mayan heartland, however, are located in flat, forested landscapes with few notable features along the horizon. Only a green sea of the floral canopy meets the eye of an observer standing on a tall pyramid. By punctuating the horizon, the eastern structures of E-Group complexes could be used to mark the solar extremes. Sunrise behind the northernmost structure of the eastern platform would be observed on the summer solstice. Sunrise behind the southernmost structure marked the winter solstice. The equinoxes could be marked halfway between, when the Sun rose due east. Scholars are still debating key factors of these complexes, but their religious significance is well attested. Caches of finely worked jade and ritual pottery reflect a cosmology oriented around the four cardinal directions, which may have coordinated with the E-Group's division of the year. Fading knowledge K'ahk' Uti' Witz' K'awiil's citizenry, however, would have been less attuned to direct celestial observations than their ancestors. By the seventh century, Mayan political organization had changed significantly. Copan had grown to as many as 25,000 residents, and agricultural technologies also changed to keep up. Cities of the Classic period practiced multiple forms of intensive agriculture that relied on sophisticated water management strategies, buffering the need to meticulously follow the horizon movement of the Sun. E-Group complexes continued to be built into the Classic period, but they were no longer oriented to sunrise, and they served political or stylistic purposes rather than celestial views. Such a development, I think, resonates today. People pay attention to the changing of the seasons, and they know when the summer solstice occurs thanks to a calendar app on their phones. But they probably don't remember the science: how the tilt of the Earth and its path around the Sun make it appear as though the Sun itself travels north or south along the eastern horizon. United through ritual During the mid-seventh century, K'ahk' Uti' Witz' K'awiil had developed ambitious plans for his city – and astronomy provided one opportunity to help achieve them. He is known today for his extravagant burial chamber, exemplifying the success he eventually achieved. This tomb is located in the heart of a magnificent structure, fronted by the 'Hieroglyphic Stairway ': a record of his dynasty's history that is one of the largest single inscriptions in ancient history. Eying opportunities to transform Copan into a regional power, K'ahk' Uti' Witz' K'awiil looked for alliances beyond his local nobility, and he reached out to nearby villages. Over the past century, several scholars, including me, have investigated the astronomical component to his plan. It appears that K'ahk' Uti' Witz' K'awiil commissioned a set of stone monuments or 'stelae,' positioned within the city and in the foothills of the Copan Valley, which tracked the Sun along the horizon. Like E-Group complexes, these monuments engaged the public in solar observations. Taken together, the stelae created a countdown to an important calendric event, orchestrated by the Sun. Back in the 1920s, archaeologist Sylvanus Morley noted that from Stela 12, to the east of the city, one could witness the Sun set behind Stela 10, on a foothill to the west, twice each year. Half a century later, archaeoastronomer Anthony Aveni recognized that these two sunsets defined 20-day intervals relative to the equinoxes and the zenith passage of the Sun, when shadows of vertical objects disappear. Twenty days is an important interval in the Mayan calendar and corresponds to the length of a 'month' in the solar year. My own research showed that the dates on several stelae also commemorate some of these 20-day interval events. In addition, they all lead up to a once-every-20-year event called a 'katun end.' K'ahk' Uti' Witz' K'awiil celebrated this katun end, setting his plans for regional hegemony in motion at Quirigua, a growing, influential city some 30 miles away. A round altar there carries an image of him, commemorating his arrival. The hieroglyphic text tells us that K'ahk' Uti' Witz' K'awiil 'danced' at Quirigua, cementing an alliance between the two cities. In other words, K'ahk' Uti' Witz' K'awiil's 'solar stelae' did more than track the Sun. The monuments brought communities together to witness astronomical events for shared cultural and religious experiences, reaching across generations. Coming together to appreciate the natural cycles that make life on Earth possible is something that – I hope – will never fade with fashion.
