Latest news with #PopulationIII
Yahoo
17 hours ago
- Science
- Yahoo
Radio signals from the dawn of time could help 'weigh' the universe's 1st stars
When you buy through links on our articles, Future and its syndication partners may earn a commission. Astronomers could use specific radio signals from the universe's earliest epoch to "weigh" the first stars in the cosmos. The investigation could reveal more about the so-called Cosmic Dawn, the period of the universe during which darkness lifted and light became free to first stars, or "Population III" (Pop III) stars, can't be seen even with the most powerful telescopes because their light was prevented from traveling by a dense cosmic fog spread between star-forming regions that consisted mostly of hydrogen. However, during this period, around 100 million years after the Big Bang, this hydrogen created a radio signal called "the 21-centimeter signal." An international team of astronomers now suggests this signal could be used to determine how light from the first stars interacted with this cosmic fog, helping to lift it. "This is a unique opportunity to learn how the universe's first light emerged from the darkness," team leader and University of Cambridge researcher Anastasia Fialkov said in a statement. "The transition from a cold, dark universe to one filled with stars is a story we're only beginning to understand." Fialkov heads up the Radio Experiment for the Analysis of Cosmic Hydrogen (REACH) project, a radio antenna that studies the faint glow of the 21-centimeter signal to reveal more about Cosmic Dawn. Still in its calibration stage, REACH will soon be joined in its investigation of the first stars by the Square Kilometre Array (SKA), a massive array of antennas under construction in Australia and South Africa. Together, SKA and REACH will investigate the masses, luminosities, and distribution of the universe's earliest stars. In preparation for this investigation, Fialkov and colleagues developed a model to predict what observations of the 21-centimeter signal will look like for both projects. This revealed that this signal is influenced by stellar masses. "We are the first group to consistently model the dependence of the 21-centimeter signal of the masses of the first stars, including the impact of ultraviolet starlight and X-ray emissions from X-ray binaries produced when the first stars die," said Fialkov. "These insights are derived from simulations that integrate the primordial conditions of the universe, such as the hydrogen-helium composition produced by the Big Bang." While developing the model, the team studied how the mass distribution of Pop III stars influenced the 21-centimeter signal. This revealed that the connection between this signal and the first stars has been underestimated in prior research because these studies had failed to account for the number of systems composed of a dense dead star, usually a white dwarf, and an ordinary star, so-called "X-ray binaries" among Pop III stars. "The predictions we are reporting have huge implications for our understanding of the nature of the very first stars in the universe," REACH telescope Principal Investigator Eloy de Lera Acedo said. "We show evidence that our radio telescopes can tell us details about the mass of those first stars and how these early lights may have been very different from today's stars." Related Stories: — How the Rubin observatory could detect thousands of 'failed stars' — Tiny 'primordial' black holes created in the Big Bang may have rapidly grown to supermassive sizes — Could dark matter have been forged in a 'Dark Big Bang?' — Astronomers discover ultrapowerful black hole jet as bright as 10 trillion suns lit by Big Bang's afterglow REACH and SKA won't see these first stars as a telescope like the James Webb Space Telescope (JWST) does. They instead rely on scientists performing statistical analysis of the data they provide. The effort can pay dividends as it provides information about entire populations of stars, X-ray binary systems and galaxies. "It takes a bit of imagination to connect radio data to the story of the first stars, but the implications are profound," Fialkov concluded. The team's research was published on Friday (June 20) in the journal Nature Astronomy.
Yahoo
15-03-2025
- Science
- Yahoo
The universe's water is almost as old as the Big Bang itself, shocking new study hints
When you buy through links on our articles, Future and its syndication partners may earn a commission. Water may have emerged in the universe far earlier than scientists thought — and it could mean that life could be billions of years older too, new research suggests. Water is one of the most essential ingredients for life as we know it. But exactly when water first appeared has been a question of scientific interest for decades. Now, new research suggests that water likely existed 100 million to 200 million years after the Big Bang — billions of years earlier than scientists previously predicted. The research was published March 3 in the journal Nature Astronomy. The early universe was dry because it was mainly filled with very simple elements, like hydrogen, helium and lithium. Heavier elements didn't develop until the first stars formed, burnt through their fuel supplies and ultimately exploded. Such stellar explosions, known as supernovas, acted like pressure cookers that combined lighter elements into increasingly heavier ones. "Oxygen, forged in the hearts of these supernovae, combined with hydrogen to form water, paving the way for the creation of the essential elements needed for life," study co-author Daniel Whalen, an astrophysicist at the University of Portsmouth in the U.K., said in a statement. Related: 32 strange places scientists are looking for aliens To determine when water first appeared, the researchers examined the most ancient supernovas, called Population III supernovas. Whalen and his team looked at models of two types of these early star remnants: core-collapse supernovas, when a large star collapses under its own mass; and pair-instability supernovas, when a star's interior pressure suddenly drops, causing a partial collapse. The researchers found that shortly after the Big Bang, both supernova types produced dense clumps of gas that likely contained water. RELATED STORIES —Astronomers identify a celestial '3-body problem' lurking in the outer solar system —'This doesn't appear in computer simulations': Hubble maps chaotic history of Andromeda galaxy, and it's nothing like scientists expected —Unproven Einstein theory of 'gravitational memory' may be real after all, new study hints Overall, the amount of water in these gas clouds was probably pretty small — but it was concentrated in the areas where planets and stars were most likely to form, the team found. The earliest galaxies probably arose from these regions, which means that water may have already been in the mix when they formed. "This implies the conditions necessary for the formation of life were in place way earlier than we ever imagined — it's a significant step forward in our understanding of the early Universe," Whalen said. Observations from the James Webb Space Telescope, which is designed to view the universe's oldest stars, may help further validate these results.
Yahoo
07-03-2025
- Science
- Yahoo
We May Have Finally Laid Eyes on The Universe's Very First Stars
Once, there was a time before stars. In the primordial darkness, after the Big Bang, nothing drifted but a vast sea of hydrogen and helium. It wasn't until stars came along, born from crushing densities in that clumping gas, that heavier elements emerged, forged by the fusion in their powerful hearts. Or so scientists believe. We've never actually seen those first stars, known as Population III stars. A new paper may finally change that. In a preprint submitted to The Astrophysical Journal and uploaded to arXiv, a large international team of astronomers led by Seiji Fujimoto of the University of Texas at Austin has described what they think might be a galaxy in the early Universe rich in these elusive objects. This galaxy, called GLIMPSE-16403, is by no means confirmed as a Population III host. But the identification of even a candidate suggests that it's only a matter of time before we finally locate the first stars in the Universe. "This work paves a clear path for the discovery of the first Pop III galaxies," the researchers write. "Whatever the fate of the present candidates, the methods developed in this study will empower Pop III galaxy searches throughout the JWST era." The Cosmic Dawn is what we call the era that spans the first billion or so years after the Big Bang popped the Universe into existence some 13.8 billion years ago. During this time, the cosmos came together from a hot quark-gluon plasma that filled the Universe in its first moments, forming stars and galaxies that literally swept away the darkness with their blazing light. Those first Population III stars were a vital step towards the Universe we see around us today. Elements heavier than hydrogen and helium can only be created by extreme processes such as core fusion and nova explosions. Yet previous research has only yielded second-hand traces of these first generation stars, not the objects themselves. Astronomers believe that this is because Population III stars may have been particularly massive, larger than any stars around in the more recent Universe. Larger stars live much, much shorter lives than smaller ones, so those first stars may have long flickered out, leaving behind only the elements they fused in their cores to be taken up by subsequent stellar generations. Cosmologists and astronomers desperately want to see what those early stars were like. They want to find out how the lights turned on in the Cosmic Dawn, clearing the neutral hydrogen fog that rendered space opaque. Our best shot for this is JWST, the most powerful space telescope ever built, optimized for peering farther back into the early Universe than any telescope before with its infrared-sensitive eye. Seeing into the Cosmic Dawn is hard enough, but looking for a needle in that particular haystack is even harder. Fujimoto and his colleagues figured they could expedite the search by looking very, very closely at only small regions of the sky, looking for the chemical fingerprints of Population III stars. The researchers focused their efforts on galaxies with powerful hydrogen and helium emission spectra, and little evidence of other elements. Their pipeline yielded two candidates. One was only tentative; but the other, GLIMPSE-16403, hanging out in the Cosmic Dawn around 825 million years after the Big Bang, met all the criteria the researchers had specified for a Population III galaxy. This makes the galaxy the best candidate to date for finding the stars that switched on the lights in the Universe. More work will need to be done to determine the nature of the stars in GLIMPSE-16403, which might be tricky; we'd need a detailed spectrum, and that's not easy to obtain across such vast gulfs of space-time. Nevertheless, the discovery is an incredibly exciting one: the detection of Population III stars now feels like it's right around the next corner. "Exactly a hundred years ago, our cosmic horizon expanded past the edges of the Milky Way for the first time, with Andromeda and Triangulum marking the boundaries of our place in the Universe," the researchers write. "As we reflect on the profound discoveries of the last hundred years, it is intriguing to consider how those early surveyors of glass plates would view the prospect that we may soon detect the Universe's very first stars." The team's paper has been submitted to The Astrophysical Journal, and is available on arXiv. Record Discovery: Impact Crater in Australia's Outback Oldest by a Billion Years Intuitive Machines' Second Lunar Lander Touches Down, But Something Feels Familiar NASA Is Planning to Shut Down Another Piece of Voyager 2
Yahoo
03-03-2025
- Science
- Yahoo
Space breakthrough as study finds 'key ingredient for life' existed billions of years before we first thought
Water, the key ingredient for life, likely formed just after the Big Bang - suggesting it has been around billions of years longer than previously thought. A new study has suggested that water came long before galaxies, 'seeding' the formation of planets – and transforming scientists' understanding of how life began. A team of scientists from the University of Portsmouth have revealed that water already existed in the universe 100 to 200-million years after the Big Bang, the massive explosion that launched space, time and matter 13.8 billion years ago. READ MORE: I took my local non-league side to League Two on Football Manager - now I'm their chairman READ MORE: Scientist's 'reality check' warning as common diet trend might do more harm than good In the first study of its kind, researchers modelled the water in the primordial universe – the extremely hot, dense and chaotic state of the cosmos just after the Big Bang. Their findings suggest that habitable planets could have started forming much sooner than previously thought, thanks to early cosmic explosions. According to the simulations, water molecules began forming shortly after the first supernova explosions, which are known as Population III (Pop III) supernovae. These cosmic events were 'essential' for creating elements like oxygen, which are essential for water, according to the study's leader Dr Daniel Whalen, from the University of Portsmouth's Institute of Cosmology and Gravitation. Dr Whalen said: 'Before the first stars exploded, there was no water in the Universe because there was no oxygen. Only very simple nuclei survived the Big Bang - hydrogen, helium, lithium and trace amounts of barium and boron. Oxygen, forged in the hearts of these supernovae, combined with hydrogen to form water, paving the way for the creation of the essential elements needed for life." The research team studied two types of exploding stars: core-collapse supernovae, which generate some heavy elements, and the more powerful Pop III supernovae, which blast huge amounts of metals into space. They found that both types formed 'dense clumps' of gas enriched with water. Although early supernovae produced only a small amount of water, it was packed into dense gas clouds known as cloud cores, Dr Whelan explains. This is where stars and planets are believed to form. Dr Whalen said: 'The key finding is that primordial supernovae formed water in the Universe that predated the first galaxies. So water was already a key constituent of the first galaxies. This implies the conditions necessary for the formation of life were in place way earlier than we ever imagined - it's a significant step forward in our understanding of the early Universe." He added: 'Although the total water masses were modest, they were highly concentrated in the only structures capable of forming stars and planets. And that suggests that planetary discs rich in water could form at cosmic dawn, before even the first galaxies.' The study, a collaboration between the University of Portsmouth and the United Arab Emirates University. was published in the journal Nature Astronomy.
