Latest news with #CosmicDawn
Yahoo
01-07-2025
- Science
- Yahoo
Astronomers see the 1st stars dispel darkness 13 billion years ago at 'Cosmic Dawn'
When you buy through links on our articles, Future and its syndication partners may earn a commission. Astronomers have used ground-based telescopes for the first time to peer back 13 billion years in time to observe the universe when the first stars first lifted the cosmic darkness. This period, around 800 million years after the Big Bang, is known as "Cosmic Dawn," and it remains one of the most mysterious and important periods in the evolution of the universe. This new glimpse of Cosmic Dawn comes courtesy of the Cosmology Large Angular Scale Surveyor (CLASS), an array of telescopes located high in the Atacama Desert region of Northern Chile. The primary mission of CLASS is to observe the Cosmic Microwave Background (CMB), a cosmic fossil left over from an event just after the Big Bang. "People thought this couldn't be done from the ground. Astronomy is a technology-limited field, and microwave signals from the Cosmic Dawn are famously difficult to measure," team leader and Johns Hopkins professor of physics and astronomy, Tobias Marriage, said in a statement. "Ground-based observations face additional challenges compared to space. Overcoming those obstacles makes this measurement a significant achievement." Prior to around 380,000 years after the Big Bang, the infant universe would have seemed like a pretty dull place, visually at least. That is because during this period, light was unable to travel freely due to the fact that photons were endlessly scattered by free electrons. This situation changed when the universe had expanded and cooled enough to allow electrons to bond with protons and create the first neutral atoms of hydrogen. Suddenly, photons were free to travel unimpeded through the cosmos as the universe instantly went from transparent to opaque. This "first light" is seen today as the CMB. When the first stars formed, their intense radiation ripped electrons from neutral hydrogen once again, an event called "reionization," turning the universe dark again during an epoch known as the "Cosmic Dark Ages." The signal from Cosmic Dawn hunted by CLASS comes from the fingerprint of the universe's first stars within the CMB. This comes in the form of polarized microwave light around a million times fainter than standard cosmic microwaves. As you may imagine, after travelling to us for 13 billion years and more, the light from Cosmic Dawn is extremely faint. Trying to detect this polarized microwave light from Earth is extremely difficult because it is drowned out by natural events such as atmospheric changes and temperature fluctuations, as well as being obscured by human-made signals like radio waves, radar and satellite signals. Thus, this cosmic radiation is usually only hunted from space by satellites like NASA's Wilkinson Microwave Anisotropy Probe (WMAP) and the European Space Agency's Planck space telescope. That was until CLASS. The team behind this new research compared data from CLASS with observations from Planck and WMAP. This allowed them to identify sources of interference and hone in on a signal from polarized microwave light in the CMB. Polarization describes what happens when waves are oriented in the same direction. This can happen when light hits an object and scatters off it. "When light hits the hood of your car and you see a glare, that's polarization. To see clearly, you can put on polarized glasses to take away glare," said team member Yunyang Li, who was a PhD student at Johns Hopkins and then a fellow at the University of Chicago while this research was being conducted. "Using the new common signal, we can determine how much of what we're seeing is cosmic glare from light bouncing off the hood of the Cosmic Dawn, so to speak." What this team specifically aims to measure with CLASS is the probability of a photon from the CMB encountering an electron ripped free of neutral hydrogen by the universe's first stars and being scattered. Doing this should help scientists better define signals from the CMB and the initial glow of the Big Bang, thus enabling them to paint a clear picture of the infant cosmos. "Measuring this reionization signal more precisely is an important frontier of cosmic microwave background research," WMAP space mission team leader Charles Bennett said. "For us, the universe is like a physics lab. Better measurements of the universe help to refine our understanding of dark matter and neutrinos, abundant but elusive particles that fill the universe. "By analyzing additional CLASS data going forward, we hope to reach the highest possible precision that's achievable." Related Stories: — How dark energy could relieve 'Hubble tension' and galaxy headaches — Hubble trouble or Superbubble? Astronomers need to escape the 'supervoid' to solve cosmology crisis — 'Our understanding of the universe may be incomplete': James Webb Space Telescope data suggests we need a 'new cosmic feature' to explain it all This new research is built upon earlier work that saw CLASS map 75% of the night sky over Earth as it makes precise measurements of the polarization of the CMB. "No other ground-based experiment can do what CLASS is doing," said Nigel Sharp, program director in the National Science Foundation (NSF) Division of Astronomical Sciences, supporter of CLASS since 2010. "The CLASS team has greatly improved measurement of the cosmic microwave polarization signal, and this impressive leap forward is a testament to the scientific value produced by NSF's long-term support."The team's research was published on Wednesday (June 2) in The Astrophysical Journal.
Yahoo
25-06-2025
- 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.
Time of India
15-06-2025
- Science
- Time of India
13-Billion-year-old ‘Cosmic Dawn' signal captured by ground-based telescope: A breakthrough in tracing the origins of universe
In a rare and remarkable scientific achievement, scientists have detected a 13-billion-year-old microwave signal from a period known as the Cosmic Dawn. It is a time just after the Big Bang when the first stars and galaxies began to form. What makes this achievement remarkable is that the signal was picked up not from space, but using Earth-based telescopes situated at high altitudes in the Andes mountains of northern Chile. The discovery was made by astrophysicists from the CLASS (Cosmology Large Angular Scale Surveyor) project. The project is funded by the US National Science Foundation. These weak signals of polarised microwave radiation provide rare insights into the early universe and reveal how the first cosmic structures influenced light leftover from the Big Bang. This is the first time such a faint and ancient signal has been observed from the ground. The breakthrough was achieved by the team led by Professor Tobias Marriage of Johns Hopkins University (JHU). This major feat defies previous assumptions that these signals could only be detected using space telescopes, due to the many technological and environmental obstacles faced by ground observatories. What is the Cosmic Dawn that sent the 13-billion-year-old signal The Cosmic Dawn refers to the time period between roughly 50 million and one billion years after the Big Bang. This is the period when the first stars, galaxies, and black holes began to form. It was like a dawn for the Universe. Before this phenomena, the universe was in a dark, neutral state with no sources of light. The earliest stars also known as Population III stars ignited nuclear fusion and emitted intense ultraviolet radiation that lit up the universe and began the process of reionization. This radiation ionized the surrounding hydrogen gas which allow light to travel freely through space for the first time. by Taboola by Taboola Sponsored Links Sponsored Links Promoted Links Promoted Links You May Like Giao dịch vàng CFDs với sàn môi giới tin cậy IC Markets Tìm hiểu thêm Undo During this era, small, irregular galaxies started to assemble, and early black holes likely formed from the collapse of massive stars. These events fundamentally changed the nature of the cosmos. By studying light from this time, such as polarised microwave signals left on the cosmic microwave background, scientists can learn how the first luminous objects shaped the universe's structure. The Cosmic Dawn marks the universe's transition from darkness to light and holds key insights into how modern galaxies, including our own- Milky way, came to be. Why detecting this signal is so difficult and significant The microwaves that scientists are looking for from the Cosmic Dawn are extremely faint. It is about a million times weaker than regular cosmic microwave background radiation. These polarised microwave signals are measured in mere millimetres of wavelength and are easily drowned out by earthly interference such as radio broadcasts, radar signals, satellites, and even atmospheric conditions like humidity or temperature shifts. According to researchers, even under ideal conditions, detecting these signals requires highly sensitive and precisely calibrated instruments. CLASS telescopes were custom-designed for this task and strategically placed in high-altitude regions of Chile, where the thinner, drier air provides a clearer view of the universe. How the CLASS team overcome the odds: A first feat from Earth 'People thought this couldn't be done from the ground,' said Prof. Tobias Marriage. 'Astronomy is a technology-limited field, and microwave signals from the Cosmic Dawn are famously difficult to measure. Ground-based observations face additional challenges compared to space. Overcoming those obstacles makes this measurement a significant achievement.' The CLASS team addressed these challenges by cross-referencing their data with results from previous space missions, such as NASA's Wilkinson Microwave Anisotropy Probe (WMAP) and the European Space Agency's Planck telescope. By identifying and eliminating interference, they were able to isolate a consistent signal from the polarised light. It confirmed that it originated from the early universe. The polarised microwave light Light becomes polarised when it bounces off surfaces or particles, causing the waves to align in a particular direction. A simple example is sunlight reflecting off a car hood, which creates a glare—one that can be reduced with polarised sunglasses. Similarly, ancient cosmic light that interacted with early matter became polarised. 'Using the new common signal, we can determine how much of what we're seeing is cosmic glare from light bouncing off the hood of the cosmic dawn, so to speak,' explained Dr. Yunyang Li, one of the study's co-authors and a researcher affiliated with Johns Hopkins and the University of Chicago. New path to explore the origins of the universe The CLASS project has opened a powerful new window into understanding the origins of the universe. The study of these signals can help scientists to see how the first light sources interacted with matter. They can trace how early stars triggered the formation of galaxies. These processes shaped large-scale structures that still define the universe today. This research opens the door to new discoveries. It gives scientists a roadmap to explore the earliest and most mysterious parts of the universe without relying only on space missions. It proves that advanced ground-based technology, when combined with clever methodology and favourable locations, can rival even space telescopes in tracing the earliest chapters of cosmic history. This research validates the capabilities of Earth-based astronomy and paves the way for deeper studies into the birth of stars, the formation of galaxies, and the evolution of the universe itself.
Indian Express
12-06-2025
- Science
- Indian Express
Scientists detect 13 billion-year old signal from ‘Cosmic Dawn' using Earth-based telescopes
In what can be called a truly unique accomplishment, scientists seem to have detected a 13 billion-year-old signal using Earth-based telescopes. This feat allow them to see how the first stars impacted light emitted from the Big Bang. Astrophysicists measured polarised microwave light to create a clearer picture of what is known as Cosmic Dawn. They traced this by using telescopes high in the Andes mountains of northern Chile. Cosmic Dawn refers to the period roughly between 50 million to one billion years after the Big Bang, a time when the first stars, black holes, and galaxies were reportedly formed. The research led by Tobias Marriage, professor of physics and astronomy at Johns Hopkins University (JHU), is the first time ground-based observations have captured signals from the Cosmic Dawn. 'People thought this couldn't be done from the ground. Astronomy is a technology-limited field, and microwave signals from the Cosmic Dawn are famously difficult to measure,' Marriage was quoted as saying by the JHU website. 'Ground-based observations face additional challenges compared to space. Overcoming those obstacles makes this measurement a significant achievement,' he added. According to the official JHU website, cosmic microwaves are barely millimetres in wavelength and are very hard to detect. The signal from polarised microwave light is about a million times fainter, making it much more difficult to trace. Meanwhile, on Earth, broadcast radio waves, radar and satellites can drown their signal, and changes in the atmosphere, weather and even temperature can distort it. The researchers claimed that even under perfect conditions, measuring this type of microwave would need highly sensitive equipment. Scientists from the US National Science Foundation's Cosmology Larger Angular Scale Surveyor, or CLASS project, used telescopes that have been specifically designed to detect traces left by the first stars in the relic big bang light. This was previously only accomplished by technology deployed in space, such as the US National Aerospace and Space Administration Wilkinson Microwave Anisotropy Probe (WMAP) and European Space Agency Planck space telescopes. As part of the project, the researchers compared the CLASS telescope data with data from the Planck and WMAP missions. They identified interference and narrowed in on a common signal from the polarised microwave light. Polarisation is when light waves collide into something and scatter. 'When light hits the hood of your car and you see a glare, that's polarisation. To see clearly, you can put on polarised glasses to take away glare,' said author Yunyang Li, who was a PhD student at Johns Hopkins and then a fellow at the University of Chicago during the research. 'Using the new common signal, we can determine how much of what we're seeing is cosmic glare from light bouncing off the hood of the cosmic dawn, so to speak.'
Yahoo
12-06-2025
- Science
- Yahoo
The Universe's Largest Map Has Arrived, And You Can Stargaze Like Never Before
After many hours of staring unblinking at a small patch of sky, JWST has given us the most detailed map ever obtained of a corner of the Universe. It's called the COSMOS-Web field, and if that sounds familiar, it's probably because an incredible image of it dropped just a month ago. That, however, was just a little taste of what has now come to pass. The full, interactive map and all the data have just dropped, a map that vastly outstrips the famous Hubble Ultra Deep Field's 10,000 galaxies. The new map contains nearly 800,000 galaxies – hopefully heralding in a new era of discovery in the deepest recesses of the Universe. "Our goal was to construct this deep field of space on a physical scale that far exceeded anything that had been done before," says physicist Caitlin Casey of the University of California Santa Barbara, who co-leads the COSMOS collaboration with Jeyhan Kartaltepe of the Rochester Institute of Technology. "If you had a printout of the Hubble Ultra Deep Field on a standard piece of paper, our image would be slightly larger than a 13-foot by 13-foot-wide mural, at the same depth. So it's really strikingly large." JWST is our best hope for understanding the Cosmic Dawn, the first billion or so years after the Big Bang, which took place around 13.8 billion years ago. This epoch of the Universe is extremely difficult to observe: it's very far away, and very faint. Because the Universe is expanding, the light that travels to us from greater distances is stretched into redder wavelengths. With its powerful resolution and infrared capabilities, JWST was designed for just these observations: finding the faint light from the dawn of time which informs us on the processes that gave rise to the Universe we see around us today. The COSMOS-Web image covers a patch of sky a little bigger than the area of 7.5 full Moons, and peers back as far as 13.5 billion years, right into the time when the opaque primordial fog that suffused the early Universe was beginning to clear. There, the researchers are looking not just for early galaxies, they're looking for an entire cosmic ecosystem – an interactive gravitational dance of objects bound by the cosmic web of dark matter that spans the entire Universe. JWST data collected to date indicates that even with Hubble data, we've barely scratched the surface of what lurks within the Cosmic Dawn. "The Big Bang happens and things take time to gravitationally collapse and form, and for stars to turn on. There's a timescale associated with that," Casey says. "And the big surprise is that with JWST, we see roughly ten times more galaxies than expected at these incredible distances. We're also seeing supermassive black holes that are not even visible with Hubble." This profusion of well-formed galaxies hasn't just surprised astronomers – it's given them a whopping great puzzle to solve. According to our current understanding of galaxy evolution, not enough time had elapsed since the Big Bang for them to have formed. Even one is a bit of a head-scratcher – but the numbers in which JWST is finding them just boggle the mind. With access to datasets free and available to everyone who wants to take a crack, however, we may get a few answers. "A big part of this project is the democratization of science and making tools and data from the best telescopes accessible to the broader community," Casey says. "The best science is really done when everyone thinks about the same data set differently. It's not just for one group of people to figure out the mysteries." Papers on the data have been submitted to the Astrophysical Journal and Astronomy & Astrophysics. Meanwhile, you can head over to the COSMOS-Web interactive website and muck about zooming through the Universe nearly all the way back to the beginning of time. Giant Jets Bigger Than The Milky Way Seen Shooting From Black Hole Humanity Has Just Glimpsed Part of The Sun We've Never Seen Before 'City-Killer' Asteroid Even More Likely to Hit The Moon in 2032
