Latest news with #darkenergy
Yahoo
4 days ago
- Science
- Yahoo
NASA's Roman Space Telescope could discover 100,000 new cosmic explosions: 'We're definitely expecting the unexpected'
When you buy through links on our articles, Future and its syndication partners may earn a commission. It's little wonder that astronomers are excited for the launch of NASA's next big space telescope project, the Nancy Grace Roman Telescope. Recent research has suggested that Roman, currently set to launch no later than May 2027, will discover as many as 100,000 powerful cosmic explosions as it conducts the High-Latitude Time-Domain Survey observation program. These powerful and violent events will include supernovas that signal the deaths of massive stars, kilonovas, which happen when two of the universe's most extreme dead stars, or "neutron stars," slam together, and "burps" of feeding supermassive black holes. Roman could even detect the explosive destruction of the universe's first generation of stars. These explosions could help scientists crack the mystery of dark energy, the placeholder name for the strange force that is causing the expansion of the universe to accelerate, and a multitude of other cosmic conundrums. "Whether you want to explore dark energy, dying stars, galactic powerhouses, or probably even entirely new things we've never seen before, this survey will be a gold mine," research leader Benjamin Rose, an assistant professor at Baylor University, said in a statement. Roman will hunt white dwarfs that go boom! The High-Latitude Time-Domain Survey will obtain its explosive results by scanning the same large region of space every five days for a period of two years. These observations will then be "stitched together" to create movies revealing a wealth of cosmic explosions. Many of these will be Type Ia supernovas, a type of cosmic explosion that occurs when a "dead star" or white dwarf feeds on a companion star so ravenously that it blows its top. These cosmic explosions are vital to astronomers because their light output and peak brightness are so regular from event to event that they can be used to measure cosmic distances. This regularity means astronomers refer to Type Ia supernovas as "standard candles." This new research, which simulated Roman's entire High-Latitude Time-Domain Survey, suggests the space telescope could reveal up to 27,000 new Type Ia supernovas. That is about 10 times as many of these white dwarf destroying explosions as the combined harvest of all previous surveys. By looking at standard candles across differing vast distances, astronomers are essentially looking back into cosmic time, and that allows them to determine how fast the universe was expanding at these times. Thus, such a wealth of Type Ia supernovas should reveal hints at the secrets of dark energy. This could help verify recent findings from the Dark Energy Spectroscopic Instrument (DESI) that suggest this strange force is actually weakening over time. "Filling these data gaps could also fill in gaps in our understanding of dark energy," Rose explained. "Evidence is mounting that dark energy has changed over time, and Roman will help us understand that change by exploring cosmic history in ways other telescopes can't." Dying stars tell the tale of the stellar life cycle The team estimates that as many as 60,000 of the 100,000 cosmic explosions that could be detected by Roman will be so-called "core collapse supernovas." These occur when massive stars at least 8 times heavier than the sun reach the end of their nuclear fuel and can no longer support themselves against gravitational collapse. As these stars' cores rapidly collapse, the outer layers are blasted away in supernovas, spreading the elements forged by these stars through the cosmos to become the building blocks of the next generation of stars, their planets, and maybe even lifeforms dwelling on said planets. Core collapse supernovas leave behind either neutron stars or black holes, depending on the mass of the progenitor star. This means that while they can't help unravel the mystery of dark energy like Type Ia supernovas may, they can tell the tale of stellar life and death. "By seeing the way an object's light changes over time and splitting it into spectra — individual colors with patterns that reveal information about the object that emitted the light—we can distinguish between all the different types of flashes Roman will see," research team member Rebekah Hounsell from NASA's Goddard Space Flight Center explained. "With the dataset we've created, scientists can train machine-learning algorithms to distinguish between different types of objects and sift through Roman's downpour of data to find them. "While searching for Type Ia supernovas, Roman is going to collect a lot of cosmic 'bycatch'—other phenomena that aren't useful to some scientists, but will be invaluable to others." Rare cosmic gems and pure gold kilonovas One of the rarer events that Roman could also detect occurs when black holes devour unfortunate stars that wander too close to them. During these tidal disruption events (TDEs), the doomed star is ripped apart by the tremendous gravitational influence of the black hole via the immense tidal forces it generates. Though much of the star is consumed by the black hole, these cosmic titans are messy eaters, meaning the vast amount of that stellar material is vomited out at velocities approaching the speed of light. This jet of matter and the stellar material of the destroyed star that settles around the black hole in a flattened swirling cloud called an accretion disk generate emissions across the electromagnetic spectrum. Roman will hunt these emissions to detect TDEs, with this team predicting that the High-Latitude Time-Domain Survey will turn up around 40 of these star-destroying events. Even more elusive than TDEs are kilonovas, explosive bursts of light that occur when two neutron stars smash together and merge. The team estimates that Roman could uncover around 5 new kilonovas, and while this is a small harvest, these observations could be vital to understanding where precious metals like gold and silver come from. Though most of the elements we see around us are generated at the heart of stars, even these stellar furnaces lack the pressures and temperatures needed to form elements heavier than iron. The environments around neutron star collisions are thought to be the only furnaces in the cosmos extreme enough to generate elements like gold, silver and plutonium. These would start life as even heavier elements that are unstable and rapidly decay. This decay releases the light seen as kilonovas, and thus studying that light is vital to understanding that process. The study of kilonovas could also help determine what types of celestial bodies are created when neutron stars merge. This could be an even larger neutron star that rapidly collapses into a black hole, an immediately formed black hole, or something entirely new and unthought of. Thus far, astronomers have only definitively confirmed the detection of one kilonova, meaning even another five would be a real boon to science. Roman looks for instability in the first stars Perhaps the most exciting cosmic explosion discovery that Roman could make would be the observation of the strange explosive death of the universe's first stars. Currently, it is theorized that these early massive stars may have died differently than modern stars. Rather than undergoing the core collapse described above, gamma-rays within the first stars could have generated matter-antimatter pairs in the form of electrons and positrons. These particles would meet and annihilate each other within the star, and this would release energy, resulting in a self-detonation called a "pair-instability supernova.' These blasts are so powerful that it is theorized that they leave nothing behind, barring the fingerprint of elements generated during that star's lifetime. As of yet, astronomers have dozens of candidates for pair-instability supernovas, but none have been confirmed. The team's simulation suggests that Roman could turn up as many as ten confirmed pair-instability supernovas. "I think Roman will make the first confirmed detection of a pair-instability supernova," Rose said. "They're incredibly far away and very rare, so you need a telescope that can survey a lot of the sky at a deep exposure level in near-infrared light, and that's Roman." Related Stories: — New kind of pulsar may explain how mysterious 'black widow' systems evolve — Hear 'black widow' pulsar's song as it destroys companion —NASA X-ray spacecraft reveals secrets of a powerful, spinning neutron star The team intends to perform a further simulation of Roman's study of the cosmos, which could indicate its capability to spot and even wider array of powerful and violent events, maybe even some that haven't yet been theorized. "Roman's going to find a whole bunch of weird and wonderful things out in space, including some we haven't even thought of yet," Hounsell concluded. "We're definitely expecting the unexpected." This research was published on Tuesday (July 15) in The Astrophysical Journal. Solve the daily Crossword
News.com.au
08-07-2025
- Science
- News.com.au
Study reveals ‘death date' of the universe before ‘Big Crunch' occurs
Time to get your affairs in order — we only have 20 billion years left. That is according to researchers who have published a new study claiming that our once-believed ever-expanding universe will actually begin to shrink in seven billion years. The study, which was published by physicists from Cornell University, Shanghai Jiao Tong University, and other institutions, suggests that the universe will reach a peak size. After that point, the universe will begin contracting until everything collapses back into a single point. It's essentially a reverse Big Bang, which scientists have dubbed the 'Big Crunch'. Using data from a number of astronomical surveys including the Dark Energy Survey and the Dark Energy Spectroscopic Instrument, the researchers predict that this 'Big Crunch' will occur in approximately 33.3 billion years. With the universe currently 13.8 billion years old, this gives Earth and everything else roughly 20 billion years before entering oblivion, according to the study. And considering the Earth is expected to be engulfed by our dying sun in approximately seven billion years, it's probably not something anyone will have to worry about too much. The theory is that the universe expands like a 'rubber band' – eventually, the elastic force becomes stronger than the expansion, causing everything to snap back together. The researchers' theory hinges on dark energy, a mysterious force that makes up about 70 per cent of the known universe. Dark energy has long been believed to be the driving force behind the expansion of the universe. However, recent observations suggest the force might actually be dynamic – meaning it can only expand so much until it shrinks again. The new model proposed by researchers suggests the universe will continue expanding but at a gradually slowing rate. At its maximum size, about 69 per cent larger than the size it is today, a gradual contraction will begin. Several major astronomical projects launching in the coming years aim to provide more information on the behaviour of dark energy. These missions could confirm or rule out a 'Big Crunch' scenario. Even if the terrifying outcome is confirmed, a 20 billion year countdown is hardly a reason to panic. For context, complex life on Earth has existed for only about 600 million years – a fraction of time in comparison. 20 billion years down the line, the Sun will have died and our galaxy will have collided with the neighbouring Andromeda galaxy long before 'the great end'. The prediction also comes with a significant level of uncertainty. The researchers have acknowledged that their model has large margins of error due to limited observational data. So, alternative scenarios – including eternal expansion – are still possible.
Daily Mail
07-07-2025
- Science
- Daily Mail
Scientists reveal 'death date' of the universe is sooner than previously believed
The universe will not last forever. In fact, scientists have revealed that its lifespan is almost half over already. A team from the US and China have discovered that our universe will reach its 'death date' and stop expanding when it turns 33.3 billion years old. Since the universe is estimated to be roughly 13.8 billion years old right now, that leaves just over 19 billion years to go before everything ends in what scientists call a 'Big Crunch.' While the universe has been expanding outward since the Big Bang, the massive explosion believed to have kickstarted everything in existence, the big crunch would be the reverse - where all matter collapses back into a single point of energy. Researchers from New York's Cornell University and China's Shanghai Jiao Tong University created a new cosmic model that suggests dark energy, the force believed to be driving the universe's expansion, will weaken over time and succumb to gravity. Scientists are still trying to prove that dark energy actually exists, but they believe it acts like a repulsive force, counteracting gravity's desire to pull everything together. If dark energy finally fades after 33.3 billion years, as proposed in the new study, gravity from all the stars, galaxies, and black holes would essentially force the universe to cave in under its own weight. This updated model of the universe now provides a much shorter timeline for our existence, which previous theories suggested might keep going without any limitations. While dark matter is a type of matter which can't be observed or seen, dark energy is a type of energy which doesn't interact in a normal way with matter. Scientists have proposed that these two things might make up the vast majority of the universe NASA's Chelsea Gohd explained in a statement: 'What exactly is dark energy? The short answer is: We don't know. But we do know that it exists, it's making the universe expand at an accelerating rate, and approximately 68.3 to 70 percent of the universe is dark energy.' In the new study, scientists focused on the role of dark energy in this process, using a model called the axion Dark Energy (aDE) model to interpret recent data suggesting that dark energy behaves differently than previously thought. Scientists believed dark energy was a cosmological constant, a fixed, unchanging energy density driving the universe's accelerated expansion indefinitely. This includes a recent study from 2020 in Astronomy & Astrophysics which concluded that the universe's dark energy has a positive cosmological constant, meaning its value never drops off and keeps allowing the universe to grow. However, the new aDE model found dark energy may actually have a negative cosmological constant of around -1.61, which suggests the universe could eventually reach a maximum size and then collapse in a Big Crunch. 'The age of our universe is of foundational importance in cosmology. Since the establishment of the Big Bang Theory, we know it is finite,' the researchers wrote on the pre-print server Arxiv. 'Using the best-fit values of the model as a benchmark, we find the lifespan of our universe to be 33 billion years,' they added in the study submitted for publication in the Journal of Cosmology and Astroparticle Physics. The researchers analyzed recent data from the Dark Energy Survey (DES) and the Dark Energy Spectroscopic Instrument (DESI). These projects studied how fast the universe is expanding by looking at things like exploding stars (supernovae) and the way galaxies are spread out. The data revealed that dark energy might not be as steady as several previous studies previously concluded. Study authors used the aDE model, which includes a cosmological constant (a value that affects how the universe expands or contracts) and an ultra-light particle called an axion. By fitting this model to the data, they estimated key values, like the cosmological constant and the equation of state (a measure of dark energy's behavior). They then used these values to predict the universe's future, calculating when it might stop expanding and collapse. Unlike standard models which assumed that dark energy is fixed, this model allowed dark energy to weaken over time as the axion field evolves. An axion field is like an invisible, super-light energy wave that spreads throughout the entire universe, kind of like ripples on a pond but existing everywhere in space. Allowing dark energy to be flexible in this way revealed that this repulsive force could have a 'best-fit value' which is negative, meaning it'll fade away as more time since the Big Bang passes. There's still a lot of uncertainty concerning the end of the universe as we know it. For one, scientists still don't even know what dark energy really is. NASA has come up with four theories about this invisible force that could be holding back the end of time. One possibility is that it's vacuum energy, a constant background energy in space tied to Albert Einstein's cosmological constant. The theory pushes the universe to expand faster but has created a puzzle for modern scientists because its predicted strength doesn't match newer observations. Dark energy could be a changing energy field or fluid, nicknamed quintessence, that fills space and acts opposite to normal matter, varying across time and space to drive the universe's accelerated expansion. NASA has also speculated that dark energy might come from defects in the universe's fabric, like hypothetical one-dimensional 'wrinkles' called cosmic strings, formed when the universe was young, pushing space outward. However, researchers suggest it could be explained by a flaw in Einstein's theory of gravity, meaning the universe's expansion does not rely on dark energy at all.
The Sun
07-07-2025
- Science
- The Sun
‘Death date' of universe revealed as scientists predict when ‘shrinking' will start before ‘Big Crunch' wipes us all out
THE universe will start to shrink in just 7billion years, a new study has claimed, upending the prediction that space is ever-expanding. The study, published by physicists from Cornell University, Shanghai Jiao Tong University, and other institutions, suggests that the universe will reach a peak size. After that point, the universe will begin contracting until everything collapses back into a single point. A reverse Big Bang of sorts, which scientists have dubbed the "Big Crunch". Using data from a number of astronomical surveys including the Dark Energy Survey and the Dark Energy Spectroscopic Instrument, the researchers predict that this "Big Crunch" will occur in approximately 33.3billion years. With the universe currently 13.8billion years old, this gives Earth and everything else roughly 20billion years before entering oblivion, according to the study. The theory is that the universe expands like a "rubber band" - eventually, the elastic force becomes stronger than the expansion, causing everything to snap back together. The researchers' theory hinges on dark energy, a mysterious force that makes up about 70 per cent of the known universe. Dark energy has long been believed to be the driving force behind the expansion of the universe. However, recent observations suggest the force might actually be dynamic - meaning it can only expand so much until it shrinks again. The new model proposed by researchers suggests the universe will continue expanding but at a gradually slowing rate. At its maximum size, about 69 per cent larger than the size it is today, a gradual contraction will begin. Mystery Martian hills found on Mars sparking hope 'time capsule' mounds will solve biggest mystery from 4BILLION yrs ago Several major astronomical projects launching in the coming years aim to provide more information on the behaviour of dark energy. These missions could confirm or rule out a "Big Crunch" scenario. Even if the terrifying outcome is confirmed, a 20billion year countdown is hardly a reason to panic. For context, complex life on Earth has existed for only about 600million years - a fraction of time in comparison. 20billion years down the line, the Sun will have died and our galaxy will have collided with the neighbouring Andromeda galaxy long before 'the great end'. The prediction also comes with a significant level of uncertainty. The researchers have acknowledged that their model has large margins of error due to limited observational data. So, alternative scenarios - including eternal expansion - are still possible. 2
Yahoo
24-06-2025
- Science
- Yahoo
Vera C Rubin Observatory reveals 1st stunning images of the cosmos. Scientists are 'beyond excited about what's coming'
When you buy through links on our articles, Future and its syndication partners may earn a commission. The Vera C. Rubin Observatory has released its first images as it begins its 10-year mission conducting the Legacy Survey of Space and Time (LSST). The LSST will revolutionize astronomy with one of its primary aims being the investigation of dark energy, the mysterious force driving the accelerating expansion of the universe, and dark matter, the strange substance that accounts for 85% of the "stuff" in the cosmos but remains effectively its perch atop Cerro Pachón in Chile, a mountain that rises around 5,200 feet (1,600 meters) above sea level, Rubin scans the entire night sky over the Southern Hemisphere once every three nights. This endeavor will be the most extensive continuous mapping of the southern sky ever attempted, and will be conducted by Rubin using the 8.4-meter Simonyi Survey Telescope and the LSST camera (LSSTCam), the largest digital camera ever constructed at around the size of a small car. Just one image from the LSSTCam covers an area equivalent to the size of 45 full moons in the sky. Above is the observatory's first image of the Virgo cluster, a vast cluster of galaxies located around 53.8 million light-years from Earth. The image shows a vast array of celestial objects, including galaxies and stars. Demonstrating the true potential of Rubin, this image alone contains a rich tapestry of about 10 million galaxies. Staggeringly, the ten million galaxies in the above image are just 0.05% of the number of around 20 billion galaxies that Rubin will have imaged by the end of the LSST. In fact, in a decade, Rubin will have collected data on an estimated 40 billion celestial bodies, meaning we will have seen more heavenly bodies than there are humans alive for the first time. Unsurprisingly, many of these objects are completely new and viewed by humanity for the first time today. The objects that are familiar have been highlighted in the image below. "The Vera C. Rubin Observatory will allow us to add depth and dynamism to the observation of the universe," Roberto Ragazzoni, president of the National Institute for Astrophysics (INAF), said in a statement. "With this 8-meter class telescope capable of continuously mapping the southern sky every three days, we enter the era of 'astro-cinematography', exploring a new dimension: that of time, with which we expect to study the cosmos with a new perspective, which is now possible thanks also to the use of new information technologies to process a mass of data that would otherwise be inscrutable." One of the most impressive abilities of Rubin will be its capability to study objects that change in brightness over time as it builds the "greatest movie of all time." This unique power comes from the fact that Rubin can scan the sky at superfast speeds, around 10 to 100 times faster than similar large telescopes. The "transients" it sees will include over 100 million variable stars changing their brightness because of pulsations, thermal instabilities, and even because of planets "transiting," or passing between Rubin and their visible disks. Rubin will also be able to observe millions of massive stars as they end their lives and undergo supernova explosions. The groundbreaking observatory will also investigate so-called "type Ia supernovas," triggered when dead star-white dwarfs undergo runaway nuclear explosions after overfeeding on stellar companions. Type Ia supernovas are also known as "standard candles" due to the fact that their consistent luminosities allow astronomers to use them to measure cosmic distances. Thus, Rubin will also make an indirect impact on astronomy by providing scientists with a wealth of new and better-understood distances between objects in the universe. Closer to home, by observing objects as they change in brightness in the night-sky, Rubin will provide astronomers with a better picture of asteroids and small bodies as they orbit Earth. This could help space agencies like NASA assess potential threats to Earth and defend against asteroids. The YouTube video below shows over 2,100 new asteroids discovered by Rubin in its first week of operations alone. "If something in the sky moves or changes, Rubin will detect it and distribute the information in real time to the entire world. This means that we will be able to observe transient phenomena in action, making new, often unexpected, astrophysical discoveries possible," said Sara (Rosaria) Bonito of the Board of Directors of the LSST Discovery Alliance of the Vera C. Rubin Observatory. "Rubin will produce a true multi-colored movie of the sky, lasting an entire decade. A movie that will allow us to see the universe as never before: not just through static images, but in dynamic evolution." Hours before the release of the main images above at 11 a.m. EDT (1500 GMT) on Monday (June 23), the Rubin team released several smaller "preview" images that are smaller sections of these larger images. These give the general public an opportunity to witness the incredible detail in images captured by the LSST camera. "These sneak preview images already highlight the uniqueness of Rubin to look at the cosmos in a way that we have never done before, bringing the sky to life!" Andrés Alejandro Plazas Malagón, a researcher at Stanford University and part of the Rubin Observatory's Community Science Team, told "These preview images also already highlight the sophistication and power of the software used to reduce or 'clean' the images: the LSST Science Pipelines."The image below shows the Triffid nebula (also known as Messier 20 or NGC 6514) in the top right, which is located around 9,000 light-years from Earth, and the Lagoon nebula (Messier 8 or NGC 6523), estimated to be 4,000 to 6,000 light-years away. These are regions in which clouds of gas and dust are condensing to birth new stars. The above picture combines 678 separate images taken by Rubin over just over 7 hours of observing time. By combining images like this, Rubin is capable of revealing details otherwise too faint to see or practically invisible. This reveals the clouds of gas and dust that comprise these nebulae in incredible detail. "The Trifod-Lagoon image shows these two nebulae or 'stellar nurseries' highlighting regions of gas and dust, made from about 678 individual images," Plazas Malagón said. "It's impressive how the large field of view of LSSTCam captured the scene all at once!"The image below shows a small section of Rubin's total view of the Virgo cluster. The bright foreground stars in this image are located closer to home, lying in the Milky Way. In the background are many galaxies even more distant than the Virgo cluster. The image below shows another small slice of Rubin's total view of the Virgo cluster. Visible in the lower right of the image are two prominent spiral galaxies. In the upper right of the image are three galaxies that are colliding and merging. The image also contains several other groups of distant galaxies, as well as a wealth of stars in our galaxy. It is just one 50th of the entire image it came from. "The other preview images show a fraction of the Virgo cluster, a galaxy cluster of about 1,000 galaxies. Built from about 10 hours of data, we already see the capability of Rubin to capture the faintest objects with exquisite detail, which will enable amazing science. And these images are just about 2 percent of the field of view of a single LSSTcam image!" Plazas Malagón said. Related Stories: — How the Rubin observatory could detect thousands of 'failed stars' — World's largest digital camera to help new Vera Rubin Observatory make a 'time-lapse record of the universe' (video) — Rubin Observatory aces 1st image tests, gets ready to use world's largest digital camera Following the release of these images, the next big step for Rubin with be the beginning of the LSST, which should occur over the next few months."The Vera C. Rubin Observatory and its first LSST project are a unique opportunity for the new generation," Bonito said. "It is a great legacy for anyone who wants to approach scientific disciplines, offering a revolutionary tool for astrophysics and new technologies for data interpretation."Bonito added that the astrophysics that can be done with Rubin is extremely diversified: a single observation campaign will allow us to respond to very broad scientific themes, which concern our galaxy but also dark matter, our solar system, and even the most unpredictable phenomena that occur in the sky." And with 10 years of the LSST ahead of it, the future of Rubin and astronomy in general is bright."These preview images also already highlight the sophistication and power of the LSST Science Pipelines software used to reduce or 'clean' the images," Plazas Malagón concluded. "As an observational cosmologist and having worked in the development of the LSST Science Pipelines and the characterization of the LSSTCam, I'm proud and beyond excited about what's coming!" To dive into the first image from Rubin and explore for yourself, visit the Vera C. Rubin Observatory SkyViewer page.
