Latest news with #UCSC
Yahoo
2 days ago
- Science
- Yahoo
Did 'primordial' black holes born right after the Big Bang help our universe's 1st stars form?
When you buy through links on our articles, Future and its syndication partners may earn a commission. New research suggests that primordial black holes created during the Big Bang could have played a major role in forming the universe's first stars. The findings could help to assess how suitable primordial black holes are as candidates for dark matter, the universe's most mysterious "stuff." But the study team isn't sure yet whether these black holes helped star formation, acting as "cosmic midwives" by ferrying matter to sites of stellar birth, or if they acted to suppress starbirth! The role primordial black holes played in the formation of so-called "Population III (POP III) stars" ( a confusing name for the first generation of stars) all depends on what masses these hypothetical original black holes have. "We investigated how primordial black holes — ancient black holes that may have formed in the very early universe — could have influenced the birth of the first stars," team member Stefano Profumo of the University of California at Santa Cruz (UCSC) told "Using advanced computer simulations, we found that, depending on their mass and abundance, these black holes could either speed up or delay the formation of the first stars." Profumo added that, in some cases, primordial black holes likely acted like "cosmic seeds," helping matter clump together earlier than expected. However, in other scenarios, Profumo and colleagues found that these black holes could have disrupted gas clouds, actually preventing stars from forming promptly. Primordial black holes: Friend or foe to star formation? Primordial black holes are thought to have formed as a result of density fluctuations in matter in the early universe. This is quite different from the origin of so-called stellar-mass black holes, which are created when massive stars collapse and erupt in supernovas at the end of their lives. This means that primordial black holes didn't have to wait for the first generation of stars to live and die before they could be created. Also, it doesn't place the same kinds of mass limits on primordial black holes that exist for stellar-mass black holes, as the former are created directly from early cosmic material rather than from collapsing stars, which can only be so massive. However, because primordial black holes are yet to be discovered, there isn't much else scientists can firmly say about them. Profumo explained how primordial black holes could play a role in star formation. "Massive primordial black holes can serve as powerful gravitational centers. In the early universe, they could have pulled in gas and dark matter more quickly, jump-starting the formation of small galaxies and stars," he said. "This could explain how some of the earliest galaxies we now see — thanks to the James Webb Space Telescope (JWST) — managed to form so surprisingly fast after the Big Bang." However, primordial black holes must have a certain mass to play a positive role in star birth, according to the team's simulations, which were performed using a software package called GIZMO, running the hydrodynamics of the universe's initial gas and dust. "To boost early star formation in the way we observed, the black holes would need to be quite massive — about a thousand to ten thousand times the mass of our sun," Profumo said. "At those sizes, and in the right numbers, they'd have a noticeable effect on how quickly the first stars formed." More massive primordial black holes would do this by causing density fluctuations in matter to increase. This would create more so-called dark matter haloes, vast clusters of this mysterious form of matter within which the building blocks of stars and galaxies could gather en masse. If there are too many of these massive primordial black holes, however, then stars and galaxies would form too fast, thus not reflecting our picture of the early universe. But the team found that primordial black holes with masses smaller than around 100 times that of the sun wouldn't increase density fluctuations. Instead, the team's simulations indicated that, if there were enough of these less massive primordial black holes, the influence of their gravity would generate tidal forces within vast clouds of gas and heat them. This is problematic for star formation, because stellar bodies are born when cold and over-dense clumps of gas and dust collapse under the influence of their own gravity. The more low-mass primordial black holes in the early universe, the more gas is heated and the more star formation is stunted. Thus, this is a really Goldilocks situation. To assist in star formation, the masses and population sizes of primordial black holes need to be "just right." Further investigation of these competing scenarios could tell scientists more about dark matter. Primordial black holes and dark matter Dark matter is so problematic to scientists because, despite accounting for about 85% of the matter in the universe, it remains effectively invisible. That means everything we see — stars, planets, moons, asteroids, comets, each other, and so forth — accounts for just 15% of the stuff in the universe. Scientists can gather that dark matter isn't made up of particles like electrons, protons, and neutrons, which compose the atoms of "normal" matter, because those particles interact with light, and whatever dark matter is doesn't. This has spurred a search for particles beyond the standard model of particle physics. The fact that this hunt has turned up empty has kept primordial black holes in the frame as dark matter suspects. "This research tells us that if primordial black holes do make up some or all of the dark matter, they can't just have any mass or be present in any amount," Profumo said. "If there are too many, or if they're too massive, they would cause the first stars to form much too early — before we see any signs of them. "On the other hand, if they're too small and too abundant, they can get in the way of star formation. This gives us a new way to rule out certain black hole scenarios for dark matter." Of course, primordial black holes remain hypothetical. Barring the detection of these Big Bang-generated black holes, there are other ways that astronomers could find evidence supporting the team's theory about their role in early star formation. "The effects we studied would show up during what's called the cosmic dawn — roughly 100 to 200 million years after the Big Bang. In some of our most extreme scenarios, star formation could start as early as 15 million years after the Big Bang — much earlier than traditional models suggest," Profumo said. "If telescopes like JWST or future instruments can find galaxies or stars forming very, very early in the universe, that would support the idea that something like primordial black holes helped cosmic structures form faster than usual." Related Stories: — A 'primordial' black hole may zoom through our solar system every decade — Primordial black holes may flood the universe. Could one hit Earth? — Tiny black holes left over from the Big Bang may be prime dark matter suspects The next step for the team is to move beyond the assumption that all primordial black holes would have the same masses. "Most theories suggest a mix of masses, and we want to model that more realistically," Profumo said. "We're also planning to improve the physical modeling of star formation, and to simulate larger patches of the early universe to understand how primordial black holes might have influenced not just the first stars but also the formation of early galaxies." The team's research is available as a preprint on the paper repository arXiv. Solve the daily Crossword
Hindustan Times
22-05-2025
- General
- Hindustan Times
California varsity launches Sikh studies project led by Punjab-origin scholar
The University of California, Santa Cruz, has launched a new academic initiative aimed at reshaping global perceptions of Sikhism through digital storytelling and inclusive scholarship. Led by Punjab-origin professor of economics and Sikh studies scholar Nirvikar Singh, the project seeks to offer a deeper, more nuanced understanding of Sikh history, identity, and philosophy. The project is titled 'Sikhs in the 21st Century: Remembering the Past, Engaging the Future', an official release by the university said on May 15. The initiative, housed at UCSC's Humanities Institute, produces multimedia content exploring the evolution of Sikh institutions, the impact of colonialism, and the complex identity of the Sikh diaspora. It challenges oversimplified narratives and aims to offer a more accurate and nuanced view of Sikh history and philosophy, according to the release. 'Many existing accounts lack depth or are shaped by colonial-era interpretations,' said Singh, who earlier held the Sarbjit Singh Aurora Chair of Sikh and Punjabi Studies. 'We're reexamining inherited assumptions and opening space for deeper, evidence-based engagement.' In collaboration with UC Santa Cruz's Teaching and Learning Centre, the project also creates space for voices often excluded from Western academic circles, especially young scholars from Punjab and marginalised communities in the Sikh diaspora. The videos, enriched with archival visuals, maps, and carefully curated sources, are designed to engage younger generations, including Sikh youth in India and abroad who are navigating identity in a globalised world. Simran Jeet Singh, a US-based Sikh scholar and author, praised the initiative for its intellectual rigour and cultural sensitivity. Singh said the goal is not just to correct the historical record but to 'help scholars and communities see old things in new ways,' while honouring the depth and diversity of Sikh heritage.
Time of India
21-05-2025
- General
- Time of India
UC Santa Cruz launches Sikh studies project led by Indian-origin scholar
Live Events Houston: The University of California, Santa Cruz, has launched a new academic initiative aimed at reshaping global perceptions of Sikhism through digital storytelling and inclusive scholarship. Led by Indian-origin professor of economics and Sikh studies scholar Nirvikar Singh, the project seeks to offer a deeper, more nuanced understanding of Sikh history, identity, and project is titled 'Sikhs in the 21st Century: Remembering the Past, Engaging the Future', an official release by the university said on May initiative, housed at UCSC's Humanities Institute, produces multimedia content exploring the evolution of Sikh institutions, the impact of colonialism, and the complex identity of the Sikh challenges oversimplified narratives and aims to offer a more accurate and nuanced view of Sikh history and philosophy , according to the release.(Join our ETNRI WhatsApp channel for all the latest updates)"Many existing accounts lack depth or are shaped by colonial-era interpretations," said Singh, who earlier held the Sarbjit Singh Aurora Chair of Sikh and Punjabi Studies. "We're reexamining inherited assumptions and opening space for deeper, evidence-based engagement."In collaboration with UC Santa Cruz's Teaching and Learning Centre, the project also creates space for voices often excluded from Western academic circles, especially young scholars from Punjab and marginalised communities in the Sikh videos, enriched with archival visuals, maps, and carefully curated sources, are designed to engage younger generations, including Sikh youth in India and abroad who are navigating identity in a globalised Jeet Singh, a US-based Sikh scholar and author, praised the initiative for its intellectual rigour and cultural said the goal is not just to correct the historical record but to "help scholars and communities see old things in new ways," while honouring the depth and diversity of Sikh heritage.
Irish Daily Mirror
28-04-2025
- Irish Daily Mirror
Irish woman living in US detained after travelling to Ireland to visit sick dad
An Irish woman who has been living in the US for decades was detained by border agents after returning from a trip to Ireland to visit her sick father. Cliona Ward was initially stopped in Seattle last month after attempting to return to the US following a trip to Ireland with her step-mother so they could be with her father, who is currently battling dementia. Living in Santa Cruz in California for 30 years, the 54-year old Irish woman is a permanent legal resident in the US, with a valid green card and had reportedly emigrated to the States when she was just 12 years old. Cliona was kept at the airport for a number of days owing to an allegedly expunged criminal conviction from two decades ago. She was then released so that she could bring officials the necessary documents, to prove that her records had been expunged, at San Francisco International Airport. According to the US publication Newsweek, Cliona's previous convictions include two felonies involving possession of drugs and four misdemeanours. But after showing up to the airport last Monday, April 21, she was detained by agents and is currently being held at the Tacoma Northwest Detention Centre in Washington. "She has a criminal past, but she's not a criminal. She's a person with a painful past," her sister Orla Holladay told Newsweek. She added: "Those court cases are from 20-plus years ago. She has been completely sober for 20-plus reality of the felony is that she was an addict and she was picked up for possessing the poison that she was putting into her own body." A fundraiser has been launched following Cliona's detention, raising almost €20,000 for the "private and gentle" Irish woman and her family so they can retain a lawyer to fight this "nightmare". Her sister wrote in a post on GoFundMe: "She did everything she was supposed to do in order to make reparations for that criminal conviction, and has been gainfully employed, paying taxes, and building a family in Santa Cruz." She added: "She [has] lived in Sacramento, attended UCSC and has built a life here. She has a son who is chronically ill who depends on her for care-giving. "She followed all of the instructions given to her by CBP for this supposed administrative meeting today, which was, in reality, an effort to take her into custody. "Cliona is a very private and gentle person, who wants nothing more than to return to her quiet life. "Please help her family secure the funds to retain a lawyer who can help her through this nightmare, and return her to her family and community as soon as possible. You are appreciated." So far the GoFundMe has raised $22,385 (€19,699) out of the $30,000 (€26,408) target. To donate to the fundraiser, head here. Taoiseach Micheál Martin said that the Irish government is "concerned" about this case. He told the Irish Mirror: "We are concerned about that case. Obviously, our consular officials and our consulate general in San Fran, that's where we'll be supporting and facilitating Cliona and the family to get this issue resolved. "When issues like this arise from time to time, our officials in the Department of Foreign Affairs engage with a view to getting the issues resolved. "Our advice is consistent in terms of where people have green cards, for example, or citizenship rights, there shouldn't be an issue. "We will be pursuing it on a bilateral basis to make sure that those who are legitimately entitled to be in the US are free from any challenges or difficulties of this kind. "I need to get a fuller report as there are some reports of other incidents like this. This is something we will take up with the US in bilateral meetings." The Department of Foreign Affairs told the Irish Mirror they are aware of the case and are providing consular assistance. A spokesperson said: "The Department of Foreign Affairs and Trade is aware of the case and is providing consular assistance. As with all consular cases, the Department does not comment on the details of individual cases."
Extra.ie
28-04-2025
- Politics
- Extra.ie
Irish woman legally living in US detained after visiting dad in Ireland
An Irish woman who has been living in the United States of America (USA) for three decades has been detained after she returned from a visit to Ireland to see her father who is unwell. 54-year-old Cliona Ward emigrated to the States when she was in her late teens and attended college at the University of California, Santa Cruz (UCSC). Ms Ward is a permanent legal resident with a valid green card. 54-year-old Cliona Ward emigrated to the States when she was in her late teens and attended college at the University of California, Santa Cruz (UCSC). Pic: Getty Images The mother-of-one travelled back to Ireland with her step mother in recent weeks to visit her father, who is at the end of his life and battling dementia. On returning to the States, Ward was apprehended by customs due to a conviction that was expunged 20 years ago. Sharing her story on Go Fund Me, the woman's sister Orla Holladay explained: 'She did everything she was supposed to do in order to make reparations for that criminal conviction, and has been gainfully employed, paying taxes, and building a family in Santa Cruz… An Irish woman who has been living in the United States of America for three decades has been detained after she returned from a visit to Ireland to see her father who is unwell. Pic: Go Fund Me 'She has a son who is chronically ill who depends on her for care-giving.' Ms Ward was released from the airport but returned on Monday to show documentation to US Customs and Border Protection officials highlighting that her conviction had been struck out. The meeting led to Ward being taken into custody, with her sister noting it was all part of a plan to do so. 'Cliona is a very private and gentle person, who wants nothing more than to return to her quiet life,' Orla wrote, 'Please help her family secure the funds to retain a lawyer who can help her through this nightmare, and return her to her family and community as soon as possible.' Ms Ward was released from the airport but returned on Monday to show documentation to US Customs and Border Protection officials highlighting that her conviction had been struck out. Pic: Nicolas Economou/NurPhoto via Getty Images The Irish native is currently at an ICE (Immigration and Customs Enforcement) detention centre in Seattle with a court date on May 7. Sharing an update on Saturday, Orla revealed she had been in contact with her sister who is 'terrified [and] scared of getting lost in the system.' Orla added that they had found a lawyer and were hopeful they would represent her sister. Orla followed up that Cliona said that she 'has been really depressed but knowing people are keeping eyes on her lifted her again.' 'She shared that although she can't speak with the majority of the women in there because most don't speak English, they have been giving each other support and there are lots of tears and hugs between the women,' Orla added. For more information and to donate to Cliona's cause go here.
