Latest news with #Mayall4-meterTelescope
CNN
02-04-2025
- Science
- CNN
New observations of the universe show how mysterious dark energy may be evolving
New hints from one of the most extensive surveys of the cosmos to date suggest that mysterious dark energy may be evolving in ways that could shift how astronomers understand the universe. Dark energy is a term scientists use to describe an energy or force that accelerates the expansion of the universe. But — although it represents 70% of the energy in the cosmos — researchers still have no idea exactly what dark energy is, said Mustapha Ishak-Boushaki, professor of physics and astrophysics at the University of Texas at Dallas. Ishak-Boushaki is a cochair of a working group for the Dark Energy Spectroscopic Instrument collaboration, known as DESI. The instrument, now in its fourth year of surveying the sky, can observe light from 5,000 galaxies at the same time. When the project concludes next year, it will have measured the light of about 50 million galaxies. The collaboration, which includes more than 900 researchers, shared the latest data release from DESI's first three years of observations on March 19. Among its findings are the measurements of nearly 15 million galaxies and quasars, some of the brightest objects in the universe. Ishak-Boushak helped lead the analysis of the latest DESI data release, which suggests that dark energy — long called a 'cosmological constant' given that astronomers thought it was unchanging — is behaving in unexpected ways and may even be weakening over time. 'The discovery of dark energy, nearly 30 years ago, was already the biggest surprise of my scientific lifetime,' said David Weinberg, a professor of astronomy at The Ohio State University who contributed to the DESI analysis, in a statement. 'These new measurements offer the strongest evidence so far that dark energy evolves, which would be another mind-blowing change to our understanding of how the universe works.' The findings bring astronomers another step closer to unmasking the mysterious nature of dark energy, which may mean that the standard model of how the universe works could also require an update, scientists say. The Dark Energy Spectroscopic Instrument is atop the National Science Foundation's Nicholas U. Mayall 4-meter Telescope at Kitt Peak National Observatory in Tucson, Arizona. The instrument's 5,000 fiber-optic 'eyes' and extensive surveying capabilities are enabling scientists to build one of the largest 3D maps of the universe and track how dark energy has influenced and shaped the cosmos over the past 11 billion years. It takes time for the light from celestial objects like galaxies to travel to Earth, which means that DESI can effectively see what the cosmos was like at different points in time, from billions of years ago to the present. 'DESI is unlike any other machine in terms of its ability to observe independent objects simultaneously,' said John Moustakas, a professor of physics at Siena College and colead of the data release. The newest findings include data on more than double the cosmic objects that were surveyed and presented less than a year ago. Those 2024 revelations first hinted at how dark energy may be evolving. 'We're in the business of letting the universe tell us how it works, and maybe the universe is telling us it's more complicated than we thought it was,' said Andrei Cuceu, a postdoctoral researcher at the US Department of Energy's Lawrence Berkeley National Laboratory, which manages DESI, and cochair of DESI's Lyman-alpha working group, in a statement. 'It's interesting and gives us more confidence to see that many different lines of evidence are pointing in the same direction.' DESI can measure what scientists call the baryon acoustic oscillation, or BAO, scale — essentially how events that occurred early in the universe left behind patterns in how matter is distributed across the cosmos. Astronomers look to the BAO scale, with separations of matter by about 480 million light-years, as a standard ruler. 'This separation scale is like a really gigantic ruler in space that we can use to measure distances, and we use the combination of these distance and redshifts (speed objects are moving away from us) to measure the expansion of the universe,' said Paul Martini, a coordinator of the analysis and professor of astronomy at The Ohio State University. Measuring dark energy's influence across the history of the universe shows how dominant a force it has been. Researchers began to notice when they combined these observations with other measurements of light across the universe such as exploding stars, the gravity-warped light of distant galaxies, and the light leftover from the dawn of the universe, called the cosmic microwave background, the DESI data shows that dark energy's impact could be weakening over time. 'If this continues then eventually dark energy will not be the dominant force in the universe,' Ishak-Boushak said in an email. 'Therefore the universe expansion will stop accelerating and will go at a constant rate or even in some models could also stop and collapse back. Of course, these futures are very remote and will take billions and billions of years to happen. I've worked on the question of cosmic acceleration for 25 years, and my perspective is, if the evidence continues to grow, and it is likely to, then this will be huge for cosmology and all of physics.' There isn't enough evidence yet to declare a groundbreaking discovery that definitively says dark energy is evolving and weakening, but that could change within just a couple of years, Ishak-Boushak said. 'My first big question is if we will continue to see evidence for evolving dark energy as our measurements get better and better,' Martini said. 'If we do get to the point where the evidence is overwhelming, then my next questions will be: How does dark energy evolve? And what are the most likely physical explanations?' The new data release could also help astrophysicists better understand how galaxies and black holes evolve and the nature of dark matter. Although dark matter has never been detected, it is believed to make up 85% of the total matter in the universe. Scientists involved with the collaboration are eager to improve their measurements using DESI. 'Whatever the nature of dark energy is, it will shape the future of our universe,' said Michael Levi, DESI director and a scientist at the Lawrence Berkeley National Laboratory. 'It's pretty remarkable that we can look up at the sky with our telescopes and try to answer one of the biggest questions that humanity has ever asked.' A new experiment called Spec-S5, or Stage 5 Spectroscopic Experiment, could measure more than 10 times as many galaxies as DESI to study both dark energy and dark matter, Martini said. 'Spec-S5 would use telescopes in both the northern and southern hemispheres to map galaxies across the entire sky,' Martini said. 'We are also excited about how the (Vera) Rubin telescope will study supernovae, and provide a new, uniform dataset to study the (universe's) expansion history.' Other space observatories, like the Euclid space telescope and the Nancy Grace Roman Space Telescope, set to launch in 2027, will also contribute more key measurements of dark matter and dark energy in the coming years that could help fill in the gaps, said Jason Rhodes, an observational cosmologist at NASA's Jet Propulsion Laboratory in Pasadena, California. Rhodes, who is not involved in DESI, is the US science lead for Euclid and principal investigator for NASA's Euclid dark energy science team. Rhodes, who calls the results intriguing, said the data shows a slight but persistent tension between measurements from the early days of the universe and those from the later universe. '(This means) that our simplest model of dark energy doesn't quite allow for the early universe we observe to evolve into the late universe we observe,' Rhodes said. 'DESI results (and some other recent results) seem to indicate that a more complex model of dark energy is preferred. This is truly exciting because it may mean that new, unknown, physics governs the evolution of the universe. DESI has given us tantalizing results that may indicate a new model of cosmology is needed.'
CNN
02-04-2025
- Science
- CNN
New observations of the universe show how mysterious dark energy may be evolving
New hints from one of the most extensive surveys of the cosmos to date suggest that mysterious dark energy may be evolving in ways that could shift how astronomers understand the universe. Dark energy is a term scientists use to describe an energy or force that accelerates the expansion of the universe. But — although it represents 70% of the energy in the cosmos — researchers still have no idea exactly what dark energy is, said Mustapha Ishak-Boushaki, professor of physics and astrophysics at the University of Texas at Dallas. Ishak-Boushaki is a cochair of a working group for the Dark Energy Spectroscopic Instrument collaboration, known as DESI. The instrument, now in its fourth year of surveying the sky, can observe light from 5,000 galaxies at the same time. When the project concludes next year, it will have measured the light of about 50 million galaxies. The collaboration, which includes more than 900 researchers, shared the latest data release from DESI's first three years of observations on March 19. Among its findings are the measurements of nearly 15 million galaxies and quasars, some of the brightest objects in the universe. Ishak-Boushak helped lead the analysis of the latest DESI data release, which suggests that dark energy — long called a 'cosmological constant' given that astronomers thought it was unchanging — is behaving in unexpected ways and may even be weakening over time. 'The discovery of dark energy, nearly 30 years ago, was already the biggest surprise of my scientific lifetime,' said David Weinberg, a professor of astronomy at The Ohio State University who contributed to the DESI analysis, in a statement. 'These new measurements offer the strongest evidence so far that dark energy evolves, which would be another mind-blowing change to our understanding of how the universe works.' The findings bring astronomers another step closer to unmasking the mysterious nature of dark energy, which may mean that the standard model of how the universe works could also require an update, scientists say. The Dark Energy Spectroscopic Instrument is atop the National Science Foundation's Nicholas U. Mayall 4-meter Telescope at Kitt Peak National Observatory in Tucson, Arizona. The instrument's 5,000 fiber-optic 'eyes' and extensive surveying capabilities are enabling scientists to build one of the largest 3D maps of the universe and track how dark energy has influenced and shaped the cosmos over the past 11 billion years. It takes time for the light from celestial objects like galaxies to travel to Earth, which means that DESI can effectively see what the cosmos was like at different points in time, from billions of years ago to the present. 'DESI is unlike any other machine in terms of its ability to observe independent objects simultaneously,' said John Moustakas, a professor of physics at Siena College and colead of the data release. The newest findings include data on more than double the cosmic objects that were surveyed and presented less than a year ago. Those 2024 revelations first hinted at how dark energy may be evolving. 'We're in the business of letting the universe tell us how it works, and maybe the universe is telling us it's more complicated than we thought it was,' said Andrei Cuceu, a postdoctoral researcher at the US Department of Energy's Lawrence Berkeley National Laboratory, which manages DESI, and cochair of DESI's Lyman-alpha working group, in a statement. 'It's interesting and gives us more confidence to see that many different lines of evidence are pointing in the same direction.' DESI can measure what scientists call the baryon acoustic oscillation, or BAO, scale — essentially how events that occurred early in the universe left behind patterns in how matter is distributed across the cosmos. Astronomers look to the BAO scale, with separations of matter by about 480 million light-years, as a standard ruler. 'This separation scale is like a really gigantic ruler in space that we can use to measure distances, and we use the combination of these distance and redshifts (speed objects are moving away from us) to measure the expansion of the universe,' said Paul Martini, a coordinator of the analysis and professor of astronomy at The Ohio State University. Measuring dark energy's influence across the history of the universe shows how dominant a force it has been. Researchers began to notice when they combined these observations with other measurements of light across the universe such as exploding stars, the gravity-warped light of distant galaxies, and the light leftover from the dawn of the universe, called the cosmic microwave background, the DESI data shows that dark energy's impact could be weakening over time. 'If this continues then eventually dark energy will not be the dominant force in the universe,' Ishak-Boushak said in an email. 'Therefore the universe expansion will stop accelerating and will go at a constant rate or even in some models could also stop and collapse back. Of course, these futures are very remote and will take billions and billions of years to happen. I've worked on the question of cosmic acceleration for 25 years, and my perspective is, if the evidence continues to grow, and it is likely to, then this will be huge for cosmology and all of physics.' There isn't enough evidence yet to declare a groundbreaking discovery that definitively says dark energy is evolving and weakening, but that could change within just a couple of years, Ishak-Boushak said. 'My first big question is if we will continue to see evidence for evolving dark energy as our measurements get better and better,' Martini said. 'If we do get to the point where the evidence is overwhelming, then my next questions will be: How does dark energy evolve? And what are the most likely physical explanations?' The new data release could also help astrophysicists better understand how galaxies and black holes evolve and the nature of dark matter. Although dark matter has never been detected, it is believed to make up 85% of the total matter in the universe. Scientists involved with the collaboration are eager to improve their measurements using DESI. 'Whatever the nature of dark energy is, it will shape the future of our universe,' said Michael Levi, DESI director and a scientist at the Lawrence Berkeley National Laboratory. 'It's pretty remarkable that we can look up at the sky with our telescopes and try to answer one of the biggest questions that humanity has ever asked.' A new experiment called Spec-S5, or Stage 5 Spectroscopic Experiment, could measure more than 10 times as many galaxies as DESI to study both dark energy and dark matter, Martini said. 'Spec-S5 would use telescopes in both the northern and southern hemispheres to map galaxies across the entire sky,' Martini said. 'We are also excited about how the (Vera) Rubin telescope will study supernovae, and provide a new, uniform dataset to study the (universe's) expansion history.' Other space observatories, like the Euclid space telescope and the Nancy Grace Roman Space Telescope, set to launch in 2027, will also contribute more key measurements of dark matter and dark energy in the coming years that could help fill in the gaps, said Jason Rhodes, an observational cosmologist at NASA's Jet Propulsion Laboratory in Pasadena, California. Rhodes, who is not involved in DESI, is the US science lead for Euclid and principal investigator for NASA's Euclid dark energy science team. Rhodes, who calls the results intriguing, said the data shows a slight but persistent tension between measurements from the early days of the universe and those from the later universe. '(This means) that our simplest model of dark energy doesn't quite allow for the early universe we observe to evolve into the late universe we observe,' Rhodes said. 'DESI results (and some other recent results) seem to indicate that a more complex model of dark energy is preferred. This is truly exciting because it may mean that new, unknown, physics governs the evolution of the universe. DESI has given us tantalizing results that may indicate a new model of cosmology is needed.'
Yahoo
20-03-2025
- Science
- Yahoo
Dark energy is even stranger than we thought, new 3D map of the universe suggests. 'What a time to be alive!' (video)
When you buy through links on our articles, Future and its syndication partners may earn a commission. New results from the Dark Energy Spectroscopic Instrument (DESI) suggest that the unknown force accelerating the expansion of the universe isn't what we believed it to be. This hints that our best theory of the universe's evolution, the standard model of cosmology, could be wrong. The newly released DESI data comes from its first three years of observations collected as the instrument, mounted on the Nicholas U. Mayall 4-meter Telescope at Kitt Peak National Observatory, continues to build the largest 3D map of the universe ever created. By the time DESI completes its five-year mission next year, the instrument will have measured the light from an estimated 50 million galaxies and black hole-powered quasars, in addition to the starlight of over 10 million stars. It is the capability of DESI to capture light from 5,000 galaxies simultaneously that makes it the ideal instrument to conduct a survey large enough to investigate the properties of dark energy. This new analysis focuses on data from the first three years of DESI observations, encompassing nearly 15 million of the best-measured galaxies and quasars. "The universe never ceases to amaze and surprise us," DESI Project Scientist Arjun Dey said in a statement. "By revealing the evolving textures of the fabric of our universe as never before, DESI and the Mayall telescope are changing our very understanding of the future of our universe and nature itself." Dark energy is the placeholder name given to whatever aspect of the universe is causing the fabric of spacetime to inflate faster and faster, constantly pushing galaxies apart more rapidly. It is thought to account for around 70% of the universe's matter and energy. The mysterious "stuff" called dark matter makes up another 25%, and ordinary matter comprising stars, planets, moons, our bodies and the cat next door accounts for just 5%. Essentially, everything we understand about the universe, including all of chemistry and biology is wrapped up in that 5%! The current "best guess" at the identity of dark energy is the cosmological constant, the vacuum energy of energy space, which is baked into the pie we call the standard model of cosmology or the Lambda Cold Dark Matter (LCDM) model. However, this model is built on the presumption that dark energy, represented by the Greek letter lambda (Λ), is constant over time. Vacuum energy describes the density of particles popping in and out of existence. While "something" appearing from "nothing" sounds crazy, you can think of it as the universe having an overdraft facility. Pairs of virtual particles are allow to "borrow" some energy from the cosmos to come into existence as long as they pay it back by meeting and annihilating each other. When taken in isolation, the DESI findings don't actually challenge the picture of dark energy developed in the LCDM model. It is when the DESI data is compared with other measurements of the cosmos that problems with the cosmological constant start to manifest. DESI is hinting, and not for the first time, that dark energy isn't constant but is changing over time. Specifically, this accelerating "push" seems to be weakening. These measurements include our observations of a "fossil" light left over from an event that happened shortly after the Big Bang called the "last scattering," when the universe had expanded and cooled enough to allow electrons to bond with protons and form the first neutral atoms. The disappearance of free electrons suddenly allowed photons, the particles that make up light, to travel freely. In other words, it was as if a universal fog had lifted, and the cosmos became transparent. This first light is referred to as the "cosmic microwave background" or "CMB," and it can still be observed today. Tiny variations or "wrinkles" were "frozen into" the CMB by fluctuations in the density of matter in the early universe called baryon acoustic oscillations (BAO). As the cosmos continued to expand, so too did these wrinkles. Thus, BAO wrinkles can act as a standard measuring stick of the expansion of the universe, with their size varying at different cosmic times. This variation arises as a result of how fast the universe was expanding at those times. Thus, measuring the BAO reveals the strength of dark energy throughout the history of the cosmos, and DESI can do this more precisely than any other instrument. Changes in dark energy itself were also hinted at when DESI data was compared with observations of type Ia supernovas, cosmic explosions that occur when white dwarf stars "overfeed" on a companion star. This stolen material piles up on the surface of the stellar remnant until a thermonuclear runaway is triggered. Type Ia supernovae are so uniform in terms of their light output that astronomers can use them as "standard candles" for measuring cosmic distances. In fact, type Ia supernovas were integral to the discovery that the expansion of the universe is accelerating, the genesis of dark energy, back in 1998. These distance measurements are possible because of a phenomenon called "redshift," which occurs when the wavelength of traveling light is stretched as it crosses the expanding universe. The longer the light has traveled, the more extreme the shift toward the long wavelength "red end" of the electromagnetic spectrum. That means measuring the redshift of a very well-known and consistent source of light, a standard candle, can give distance measurements. DESI data can also be combined with observations of an effect called "gravitational lensing," the distortion of light from distant galaxies by foreground objects of great mass to show the signature of evolving dark energy. The evolution of dark energy isn't robust enough to be considered a "discovery" just yet, but different combinations of the data with other observations are pushing this concept toward what is considered the "gold standard" in physics for such a determination. In addition to unveiling these latest dark energy results on Wednesday (March 19), the DESI collaboration also announced that its Data Release 1 (DR1) is now available for anyone to explore through the National Energy Research Scientific Computing Center (NERSC). DR1 contains information regarding 18.7 million cosmic objects, including roughly 4 million stars, 13.1 million galaxies, and 1.6 million quasars. Luz Ángela García Peñaloza, a former DESI team member and a cosmologist at the Universidad ECCI in Colombia, is just one scientist who is thrilled with the new DESI results and the fact that DR1 is now available to the general astronomical community. told "I am also really excited to find out DESI has released redshift information of about 19 million galaxies and quasars. We've increased the number of identified galaxies by an order of magnitude in less than 10 years!" García Peñaloza said. "The most fascinating result of all is that different sets of observations, a combination of BAO from DESI with CMB data from Planck, and the three main sets of luminosity distances of type Ia supernovas are making a stronger case for an evolving dark energy model, disfavoring the cosmological constant. "This is getting more and more consistent with other independent cosmological tests that seem to be opening a window of opportunity for new ways to explore and study dark energy and the accelerated expansion of the universe." Related Stories: — 'Mind-blowing' dark energy instrument results show Einstein was right about gravity — again — In a way, and the dark universe grew up together — Dark energy could be getting weaker, suggesting the universe will end in a 'Big Crunch' The availability of the DR1 data means astronomers outside the DESI collaboration can now dive into this vast dataset collected between May 2021 and June 2022. "Our results are fertile ground for our theory colleagues as they look at new and existing models, and we're excited to see what they come up with," DESI director Michael Levi, a scientist at Berkeley Lab, said. "Whatever the nature of dark energy is, it will shape the future of our universe. "It's pretty remarkable that we can look up at the sky with our telescopes and try to answer one of the biggest questions that humanity has ever asked.' Meanwhile, the DESI collaboration is preparing to begin additional analyses of the new dataset to extract even more findings as DESI itself continues collecting data during its fourth year of operations. "Just amazing," García Peñaloza concluded. "What a time to be alive and to be a cosmologist!" The DESI data is discussed in a series of papers available here.
