Our understanding of black holes, time and the mysterious dark energy that dominates the universe could be revolutionized, as new University of Sheffield research helps unravel the mysteries of the cosmos.
The study uses a simplified, theoretical model of a black hole, known as a planar black hole. Unlike typical black holes, which have a spherical shape, a planar black hole's boundary is a flat, two-dimensional surface. The researchers' ongoing work suggests that the same mechanism could also apply to a typical black hole.
The scientists' findings demonstrate how, using the laws of quantum mechanics, the black hole singularity is replaced by a region of large quantum fluctuations—tiny, temporary changes in the energy of space—where space and time do not end. Instead, space and time transition into a new phase called a white hole—a theoretical region of space thought to function in the opposite way to a black hole. As such, a white hole could be where time begins.
In images of the deep universe taken by the James Webb Space Telescope Advanced Deep Extragalactic Survey, or JADES, the vast majority of the galaxies rotate in the same direction, according to research by Lior Shamir, associate professor of computer science in the Carl R. Ice College of Engineering. About two third of the galaxies rotate clockwise, while just about a third of the galaxies rotate counterclockwise.
In a random universe, the number of galaxies that rotate in one direction should be roughly the same as the number of galaxies that rotate in the other direction. The fact that James Webb Space Telescope shows that most galaxies rotate in the same direction is therefore unexpected.“It is still not clear what causes this to happen, but there are two primary possible explanations," Shamir said. "One explanation is that the universe was born rotating. That explanation agrees with theories such as black hole cosmology, which postulates that the entire universe is the interior of a black hole. But if the universe was indeed born rotating it means that the existing theories about the cosmos are incomplete.”
That could be another explanation for why such galaxies are overrepresented in the telescope observations, Shamir said. Astronomers may need to reconsider the effect of the Milky Way's rotational velocity — which had traditionally been considered to be too slow and negligible in comparison to other galaxies — on their measurements.
An international team of astronomers, including a Northwestern University astrophysicist, has traced a series of mysterious radio pulses to an unprecedented home.Starting a decade ago, astronomers have detected a pulse of radio emission every two hours, coming from the direction of the Big Dipper. After combining observations from multiple telescopes, the team can now reveal the culprit: a binary system with a dead star.According to the new study, a red dwarf and white dwarf are orbiting each other so tightly that their magnetic fields interact. Each time they bump together — which is every two hours — the interaction emits a long radio blast.
Just last November, researchers reported the discovery of a planet orbiting Barnard’s Star with a period of 3.154 days. The data hinted at the presence of three other planets, but these candidates could not be confirmed. In a new research article published today, Ritvik Basant (University of Chicago) and collaborators leveraged years of data to confirm that Barnard’s Star hosts not just one, but four planets.
Ultimately, Basant’s team confirmed the presence of four planets with minimum masses between 19% and 34% of Earth’s mass. Barnard e is possibly the lowest-mass planet to be detected using the radial-velocity method.
These planets are in remarkably close quarters, with periods of just 2.34, 3.15, 4.12, and 6.74 days. Is such a compact setup likely to be stable? Using a machine-learning algorithm, the team showed that if the planets have perfectly circular orbits, the system is stable long term. However, using the best-fitting orbital parameters — which are consistent with circular orbits within 1.5 sigma — the system became unstable within just 2,000 years. More work is needed to understand the orbits of the newfound planets and the long-term stability of the system.Now, for the million-dollar question: could any of these planets be habitable? None of the newly discovered planets lie within Barnard’s Star’s habitable zone, which spans orbital periods from 10 to 42 days. The current data also rule out the presence of habitable-zone planets with masses greater than 0.57 Earth mass, though smaller planets are still possible.
At least two mass extinction events in Earth's history were likely caused by the "devastating" effects of nearby supernova explosions, a new study suggests.Researchers at Keele University say these super-powerful blasts – caused by the death of a massive star – may have previously stripped our planet's atmosphere of its ozone, sparked acid rain and exposed life to harmful ultraviolet radiation from the Sun.They believe a supernova explosion close to Earth could be to blame for both the late Devonian and Ordovician extinction events, which occurred 372 and 445 million years ago respectively.
The researchers came to their conclusion after carrying out a "census" of massive stars within a kiloparsec (around 3,260 light-years) of the Sun. They were studying the distribution of these massive stars, known as OB stars, to learn more about how star clusters and galaxies form by using the Milky Way itself as a benchmark, and the rate at which these stars form in our galaxy. This census allowed the researchers to calculate the rate at which supernovae occur within the galaxy, which is important for observations of supernovae, and the production of supernova remnants and massive stellar remnants such as black holes and neutron stars throughout the universe.
As part of this the research team calculated the supernova rate within 20 parsecs of the Sun, or approximately 65 light-years, and compared this with the approximate rate of mass extinction events on Earth that have previously been attributed to nearby supernovae.This excludes extinction events linked to other factors such as asteroid impacts or the ice ages.
CONFIRMED AT LAST: BARNARD’S STAR HOSTS FOUR TINY PLANETSQuote Just last November, researchers reported the discovery of a planet orbiting Barnard’s Star with a period of 3.154 days. The data hinted at the presence of three other planets, but these candidates could not be confirmed. In a new research article published today, Ritvik Basant (University of Chicago) and collaborators leveraged years of data to confirm that Barnard’s Star hosts not just one, but four planets.…QuoteUltimately, Basant’s team confirmed the presence of four planets with minimum masses between 19% and 34% of Earth’s mass. Barnard e is possibly the lowest-mass planet to be detected using the radial-velocity method.…Quote These planets are in remarkably close quarters, with periods of just 2.34, 3.15, 4.12, and 6.74 days. Is such a compact setup likely to be stable? Using a machine-learning algorithm, the team showed that if the planets have perfectly circular orbits, the system is stable long term. However, using the best-fitting orbital parameters — which are consistent with circular orbits within 1.5 sigma — the system became unstable within just 2,000 years. More work is needed to understand the orbits of the newfound planets and the long-term stability of the system.Now, for the million-dollar question: could any of these planets be habitable? None of the newly discovered planets lie within Barnard’s Star’s habitable zone, which spans orbital periods from 10 to 42 days. The current data also rule out the presence of habitable-zone planets with masses greater than 0.57 Earth mass, though smaller planets are still possible.https://skyandtelescope.org/astronomy-news/confirmed-at-last-barnards-star-hosts-four-tiny-planets/Related paper:https://iopscience.iop.org/article/10.3847/2041-8213/adb8d5
The James Webb Space Telescope has captured its first direct images of carbon dioxide in a planet outside the solar system in HR 8799, a multiplanet system 130 light-years away that has long been a key target for planet formation studies.The observations provide strong evidence that the system's four giant planets formed in much the same way as Jupiter and Saturn, by slowly building solid cores. They also confirm Webb can do more than infer atmospheric composition from starlight measurements—it can directly analyze the chemistry of exoplanet atmospheres.
NASA spacecraft far from Earth has made an unexpected discovery, after turning its instruments towards a dark patch of sky at the galactic poles for over 200 hours.Studying the background light that is illuminating its journey, the New Horizons team discovered it is much brighter than expected, and they don't know why.
A surprising chemical difference between Pluto and Sedna, another dwarf planet in the distant Kuiper Belt, is helping scientists nail down their respective masses, a new study reports.
Scientists analyzing pulverized rock onboard NASA’s Curiosity rover have found the largest organic compounds on the Red Planet to date. The finding, published Monday in the Proceedings of the National Academy of Sciences, suggests prebiotic chemistry may have advanced further on Mars than previously observed.Scientists probed an existing rock sample inside Curiosity’s Sample Analysis at Mars (SAM) mini-lab and found the molecules decane, undecane, and dodecane. These compounds, which are made up of 10, 11, and 12 carbons, respectively, are thought to be the fragments of fatty acids that were preserved in the sample. Fatty acids are among the organic molecules that on Earth are chemical building blocks of life.
SummaryUnexpected, bright hydrogen emission caught astronomers by surprise.The early universe was filled with a thick fog of neutral hydrogen. Even though the first stars and galaxies emitted copious amounts of ultraviolet light, that light struggled to pierce the fog. It took hundreds of millions of years for the neutral hydrogen to become ionized, electrons stripped from protons, allowing light to travel freely through space.Astronomers are seeking to understand this unique time of transformation, known as the era of reionization. A newly discovered galaxy illuminated this era in an unexpected way. JADES-GS-z13-1, observed just 330 million years after the big bang, shows bright hydrogen emission that should have been absorbed by the cosmic fog. Theorists are struggling to explain how its light could have pierced the fog at such an early time.
Swirling through the Milky Way’s central zone, surrounding the supermassive black hole Sgr A*, dust and gases constantly churn as energetic shock waves ripple. An international scientific team using the Atacama Large Millimeter/submillimeter Array (ALMA) has sharpened our view of this action by a factor of 100, discovering a surprising new filamentary structure in this mysterious region of space.
Significantly, James’s new system is the heaviest of its type ever confirmed, with a combined mass of 1.56 times that of the Sun. At this high of a mass, this means that, no matter what, the stars are destined to explode.The explosion is not due for another 23 billion years, however, and despite being so close to our solar system, this supernova will not endanger our planet.Right now, the white dwarfs are leisurely spiralling around each other in an orbit taking longer than 14 hours. Over billions of years, gravitational wave radiation will cause the two stars to inspiral until, at the precipice of the supernova event, they will be moving so fast that they complete an orbit in a mere 30 – 40 seconds.
For the supernova event, mass will transfer from one dwarf to the other, resulting in in a rare and complex supernova explosion through a quadruple detonation. The surface of the mass-gaining dwarf detonates where it is accumulating material first, causing its core to explode second. This ejects material in all directions, colliding with the other white dwarf, causing the process to repeat for a third and fourth detonation.The explosions will completely destroy the entire system, with energy levels a thousand trillion trillion times that of the most powerful nuclear bomb.
The exoplanet, L 98-59 c, is a hot, rocky world slightly larger than Earth that orbits a bright, young star about 35 light-years away from us. While the planet itself was discovered back in 2019, a new analysis of Hubble Space Telescope observations suggests it may be capable of hosting an atmosphere, adding to the diversity of known terrestrial worlds with clearly defined "air."If confirmed, the new findings would also make L 98-59 c the first planet of its size with a detected atmosphere, astronomers say, potentially setting new constraints on the atmospheres of worlds with this size and their ability to endure extreme environments created by the harsh conditions of young, flaring stars.
Observations from NASA’s James Webb Space Telescope have provided a surprising twist in the narrative surrounding what is believed to be the first star observed in the act of swallowing a planet. The new findings suggest that the star actually did not swell to envelop a planet as previously hypothesized. Instead, Webb’s observations show the planet’s orbit shrank over time, slowly bringing the planet closer to its demise until it was engulfed in full.“Because this is such a novel event, we didn’t quite know what to expect when we decided to point this telescope in its direction,” said Ryan Lau, lead author of the new paper and astronomer at NSF NOIRLab (National Science Foundation National Optical-Infrared Astronomy Research Laboratory) in Tuscon, Arizona. “With its high-resolution look in the infrared, we are learning valuable insights about the final fates of planetary systems, possibly including our own.”Two instruments aboard Webb conducted the post-mortem of the scene – Webb’s MIRI (Mid-Infrared Instrument) and NIRSpec (Near-Infrared Spectrograph). The researchers were able to come to their conclusion using a two-pronged investigative approach.Constraining the HowThe star at the center of this scene is located in the Milky Way galaxy about 12,000 light-years away from Earth.The brightening event, formally called ZTF SLRN-2020, was originally spotted as a flash of optical light using the Zwicky Transient Facility at the Palomar Observatory in San Diego, California. Data from NASA’s NEOWISE (Near-Earth Object Wide-field Infrared Survey Explorer) showed the star actually brightened in the infrared a year before the optical light flash, hinting at the presence of dust. This initial 2023 investigation led researchers to believe that the star was more Sun-like, and had been in the process of aging into a red giant over hundreds of thousands of years, slowly expanding as it exhausted its hydrogen fuel.However, Webb’s MIRI told a different story. With powerful sensitivity and spatial resolution, Webb was able to precisely measure the hidden emission from the star and its immediate surroundings, which lie in a very crowded region of space. The researchers found the star was not as bright as it should have been if it had evolved into a red giant, indicating there was no swelling to engulf the planet as once thought.Reconstructing the SceneResearchers suggest that, at one point, the planet was about Jupiter-sized, but orbited quite close to the star, even closer than Mercury’s orbit around our Sun. Over millions of years, the planet orbited closer and closer to the star, leading to the catastrophic consequence.“The planet eventually started to graze the star's atmosphere. Then it was a runaway process of falling in faster from that moment,” said team member Morgan MacLeod of the Harvard-Smithsonian Center for Astrophysics and the Massachusetts Institute of Technology in Cambridge, Massachusetts. “The planet, as it’s falling in, started to sort of smear around the star.”In its final splashdown, the planet would have blasted gas away from the outer layers of the star. As it expanded and cooled off, the heavy elements in this gas condensed into cold dust over the next year.Inspecting the LeftoversWhile the researchers did expect an expanding cloud of cooler dust around the star, a look with the powerful NIRSpec revealed a hot circumstellar disk of molecular gas closer in. Furthermore, Webb’s high spectral resolution was able to detect certain molecules in this accretion disk, including carbon monoxide.“With such a transformative telescope like Webb, it was hard for me to have any expectations of what we’d find in the immediate surroundings of the star,” said Colette Salyk of Vassar College in Poughkeepsie, New York, an exoplanet researcher and co-author on the new paper. “I will say, I could not have expected seeing what has the characteristics of a planet-forming region, even though planets are not forming here, in the aftermath of an engulfment.”The ability to characterize this gas opens more questions for researchers about what actually happened once the planet was fully swallowed by the star.“This is truly the precipice of studying these events. This is the only one we've observed in action, and this is the best detection of the aftermath after things have settled back down,” Lau said. “We hope this is just the start of our sample.”
For some time, scientists have pondered a peculiar question: Can galaxies exist without an outer halo of dark matter? But new research flips this question around, investigating whether some dark matter haloes could exist without galaxies in their centers — like hollow Easter Eggs roaming the cosmos.
Astronomers claim to have seen the strongest evidence so far for life on another planet. But other astronomers have urged caution until the findings can be verified by other groups and alternative, non-biological explanations can be ruled out.“These are the first hints we are seeing of an alien world that is possibly inhabited,” Nikku Madhusudhan at the University of Cambridge told a press conference on 15 March.
In 2023, Madhusudhan and his colleagues used the instruments on the James Webb Space Telescope (JWST) to look at K2-18b’s atmosphere in near-infrared light, and again found evidence of water vapour, as well as carbon dioxide and methane. But they also found a tantalising hint of dimethyl sulphide (DMS), a molecule that, on Earth, is produced only by living organisms, mainly marine phytoplankton. The signs for DMS were extremely weak, however, and many astronomers argued that we would need much stronger evidence to be certain about the molecule’s presence.Now, Madhusudhan and his colleagues have used a different instrument from JWST, the mid-infrared camera, to observe K2-18b. They found a much stronger signal for DMS, as well as a possible related molecule called dimethyl disulphide (DMDS), which is also produced on Earth only by life.
The team claims that the detection of DMS and DMDS is at the three-sigma level of statistical significance, which is equivalent to a 3-in-1000 chance that a pattern of data like this ends up being a fluke. In physics, the standard threshold for accepting something as a true discovery is five sigma, which equates to a 1-in-3.5 million chance that the data is a chance occurrence.Nicholas Wogan at the NASA Ames Research Center in California says the evidence is more convincing than the 2023 results, but it still needs to be verified by other groups. Once the data is made public next week, other researchers can start to confirm the findings, but this could take weeks or months due to the difficulty of interpreting JWST data. “It’s not just like you download the data and you see if there’s DMS – it’s this super complicated process,” says Wogan.Other scientists are more sceptical about the findings. “These new JWST observations do not offer convincing evidence that DMS or DMDS are present in K2-18b’s atmosphere,” says Ryan MacDonald at the University of Michigan. “We have a boy-who-cried-wolf situation for K2-18b, where multiple previous three-sigma detections have completely vanished when subject to closer scrutiny. Any claim of life beyond Earth needs to be rigorously checked by other scientists, and unfortunately many previous exciting claims for K2-18b haven’t withstood these independent checks.”
Madhusudhan and his colleagues calculate that the possible concentrations of DMS and DMDS on K2-18b appear to be over 10 parts per million, thousands of times greater than the concentrations in Earth’s atmosphere. This could indicate a far greater amount of biological activity than on Earth, if the signal proves to be correct, but establishing that the chemicals have a biological origin will take more work, he says.“We have to be extremely careful,” said Madhusudhan. “We cannot, at this stage, make the claim that, even if we detect DMS and DMDS, that it is due to life. Let me be very clear about that. But if you take published studies so far, then there is no mechanism that can explain what we are seeing without life.”Ruling out alternative mechanisms could take some time, says Wogan. “Something like this hasn’t really been studied. DMS in a hydrogen-rich atmosphere, we don’t know a tonne about it. There would have to be a lot of work.”
