Latest news with #TheAstrophysicalJournal
15 hours ago
- Science
How a new planetarium show helped scientists unlock a cosmic secret
NEW YORK -- Scientists have unlocked one of the solar system's many secrets from an unexpected source: a planetarium show opening to the public on Monday. At the American Museum of Natural History last fall, experts were hard at work preparing 'Encounters in the Milky Way," a deep dive into our home galaxy shaped by the movements of stars and other celestial objects. They were fine-tuning a scene featuring what's known as the Oort Cloud, a region far beyond Pluto filled with icy relics from the solar system's formation. Comets can hurtle toward Earth from the cloud, but scientists have never glimpsed its true shape. One evening while watching the Oort Cloud scene, scientists noticed something strange projected onto the planetarium's dome. 'Why is there a spiral there?' said the museum's Jackie Faherty. The inner section of the Oort Cloud, made of billions of comets, resembled a bar with two waving arms, similar to the shape of our Milky Way galaxy. Scientists had long thought the Oort Cloud was shaped like a sphere or flattened shell, warped by the push and pull of other planets and the Milky Way itself. The planetarium show hinted that a more complex shape could lie inside. The museum contacted the researcher who provided the Oort Cloud data for the show, who was also surprised to see the spiral. 'It's kind of a freak accident that it actually happened,' said David Nesvorny with the Southwest Research Institute. Realizing they'd stumbled on something new, the researchers published their findings earlier this year in The Astrophysical Journal. The spiral is "a striking shift in our understanding of the outer solar system,' planetary scientist Andre Izidoro with Rice University, who was not involved with the study, said in an email. The discovery, relying on data on how celestial objects move and using simulations, will be difficult to confirm with observations. But knowing more about the orbits of distant comets could give scientists some clues, Izidoro said. While putting together the planetarium show, the museum's experts weren't expecting a window into the universe's inner workings. The show, narrated by actor Pedro Pascal, features many vivid scenes that may capture audiences more than the Oort Cloud, said the museum's Jon Parker — including an ongoing merge of the Sagittarius mini galaxy with the Milky Way. No matter how striking and beautiful the visuals of the show, the museum was committed to making it scientifically accurate. That's what created the perfect conditions to stumble upon something new, said the museum's Carter Emmart. 'You just never know what you're going to find,' Emmart said.
Yahoo
21-05-2025
- Science
- Yahoo
Why do dwarf galaxies line up? 'Zippers' and 'twisters' in the early universe may solve a galactic mystery
When you buy through links on our articles, Future and its syndication partners may earn a commission. Structures known as "zippers" and "twisters" in the early universe may explain why dwarf galaxies tend to line up with each other, as well as hint at how dark matter operates in the universe. Every major galaxy like the Milky Way has a retinue of smaller dwarf galaxies orbiting it. The Milky Way has several dozen, including the famous Large and Small Magellanic clouds. Beginning in the 1970s, astronomers noticed that these dwarf galaxies' positions and orbits weren't entirely random. Instead, dwarf galaxies tended to exist within the same plane. For example, the 11 brightest satellites of the Milky Way share a plane, and many dwarf galaxies around the Andromeda galaxy form what is known as the Great Plane of Andromeda. When confronted with an observational mystery like this, astronomers turn to computer simulations to try to understand what's going on. That's because we can see only a small fraction of all the matter in the cosmos — just the matter that emits light. The vast majority of the mass of every galaxy, both big and small, is in the form of mysterious, invisible dark matter. We can't directly observe dark matter, so we must use the simulations to piece together what that major component is doing and how it affects the visible galaxies. But computer simulations have routinely found that dwarf galaxies are just scattered everywhere, rather than being arranged into particular planes. Because alignments of dwarf galaxies appear to be common, the theory of galaxy formation is at odds with observations. In a paper submitted to The Astrophysical Journal in April, a team of researchers led by Janvi Madhani at Johns Hopkins University dug deeper into sophisticated simulations to see if they could crack the mystery. The team studied the evolution of 12 simulated galaxies that were similar to the Milky Way, following the flows of dark matter and gas over billions of years. Galaxies do not spring up in an instant. Instead, they grow over time as filaments of matter pour onto them, like a giant cosmic umbilical cord. And it's in these filaments that the researchers found how dwarf galaxies can align with each other. Previous research assumed that once dwarf galaxies formed, they would scatter into random orbits. But the new simulations followed the evolution of the gas to much greater resolution and precision, which allowed the researchers to forget assumptions and see what was actually happening. Related: The faintest star system orbiting our Milky Way may be dominated by dark matter The new study found that instead of scattering, the filaments can lock in with each other and enhance themselves. When they do this, they keep the dwarf galaxies confined to a single plane. But the orientation of that plane depends on what happens to the filaments as new streams of gas connect to the same host galaxy. Sometimes, the filaments enhance each other, in what the researchers call a "zipper" — like the zipper merge you perform on a highway on-ramp. This creates a plane of gas that eventually evolves into a collection of dwarf galaxies. Another case involves a "twister," which is when a new filament merges with an existing one with a lot of angular momentum. This shifts the position of the plane but otherwise keeps it intact. But if too many filaments connect to the same galaxy, then any pattern is destroyed and dwarf galaxies get random orbits. Overall, the researchers found that we should expect planes of dwarf galaxies in roughly half — and perhaps up to 70% — of galaxies like the Milky Way and Andromeda. RELATED STORIES: —How did Andromeda's dwarf galaxies form? Hubble Telescope finds more questions than answers —Early galaxies were shaped like surfboards and pool noodles, James Webb Space Telescope finds —James Webb Space Telescope reveals ancient galaxies were more structured than scientists thought Based on this work, there doesn't appear to be any great tension between what we expect dark matter and gas to do when they build galaxies and what actually happens. So, although it doesn't reveal a crack in our understanding of cosmology, it does solve a decades-long problem in astronomy. Astronomers are especially interested in galaxy formation, especially in the early universe. Recently, the James Webb Space Telescope revealed rather mature galaxies appearing at surprisingly early times. Those galaxies could point the way to a new cosmological paradigm, or they might just be the result of a different kind of zipper-and-twister dance. Only more observations and better simulations will tell us.
Yahoo
27-04-2025
- Science
- Yahoo
Webb telescope may have just revealed a spiral galaxy's startling secret
Scientists have found an unusual neon glow near the center of the Southern Pinwheel Galaxy for the first time. This gas needs an enormous amount of energy to shine — more than normal stars can supply. The discovery, based on data from NASA's James Webb Space Telescope, likely means the barred spiral galaxy, sometimes called Messier 83 or M83, has been harboring an active, supermassive black hole in secret. The new research, published in The Astrophysical Journal, upends prior thinking about the galaxy. Previously, it was assumed that if there were a hole in its heart, it would be dormant and certainly not shooting out high-energy radiation. "Before Webb, we simply did not have the tools to detect such faint and highly ionized gas signatures in M83's nucleus," said Svea Hernandez, an astronomer at the Space Telescope Science Institute in Baltimore, in a statement. "We are finally able to explore these hidden depths of the galaxy and uncover what was once invisible." SEE ALSO: These scientists think alien life best explains what Webb just found Dust and gas obscure the view to extremely distant and inherently dim light sources, but infrared waves can pierce through the clouds. Credit: NASA GSFC / CIL / Adriana Manrique Gutierrez illustration Black holes are some of the most inscrutable phenomena in outer space. About 50 years ago, they were little more than a theory — a kooky mathematical answer to a physics problem. Even astronomers at the top of their field weren't entirely convinced they existed. Today, not only are black holes accepted science, they're getting their pictures taken by a collection of enormous, synced-up radio dishes on Earth. Unlike a planet or star, black holes don't have surfaces. Instead, they have a boundary called an "event horizon," or a point of no return. If anything swoops too close, it will fall in, never to escape the hole's gravitational clutch. The most common kind, called a stellar black hole, is thought to be the result of an enormous star dying in a supernova explosion. The star's material then collapses onto itself, condensing into a relatively tiny area. But how supermassive black holes, millions to billions of times more massive than the sun, form is even more elusive than typical stellar black holes. Many astrophysicists and cosmologists believe these invisible giants lurk at the center of virtually all galaxies. Recent Hubble Space Telescope observations have bolstered the theory that supermassive black holes begin in the dusty cores of starburst galaxies, where new stars are rapidly assembled, but scientists are still teasing it out. The Southern Pinwheel Galaxy — about 15 million light-years away in the constellation Hydra — is one such starburst galaxy. It has baffled scientists for decades as they struggled fruitlessly to find signs of a black hole at its center. Webb, a collaboration with the European and Canadian space agencies, was mainly designed to study the early universe, star formation, and distant galaxies. But its extreme sensitivity to infrared light, invisible to peoples' eyes, gave it the power to find clues that other telescopes couldn't, said Linda Smith, a co-author on the paper. Infrared light can shine through dust, which often blocks other forms of light. This gives Webb an advantage in studying cloudy areas where stars are forming or giant black holes might be active. Though the detected signals strongly suggest the presence of a black hole, the team is considering other possible sources, such as powerful shock waves moving through space or inordinately massive stars. The researchers plan to follow up their observations with other telescopes to look at the galaxy in different ways. "Now we have fresh evidence that challenges past assumptions," Smith said.
Yahoo
25-04-2025
- Science
- Yahoo
James Webb telescope solves 'impossible' black hole mystery from the ancient universe
When you buy through links on our articles, Future and its syndication partners may earn a commission. A "fast-feeding" black hole that appeared to defy physics is actually pretty ordinary, observations from the James Webb Space Telescope (JWST) reveal. In November 2024, astronomers using JWST reported that they'd found a black hole from the early universe that appeared to be gorging on matter 40 times faster than theoretically possible. The black hole, called LID-568, was observed as it existed just 1.5 billion years after the Big Bang — much too early in the history of the universe for it to have gotten that huge. However, new research suggests that this excessive eating rate may have been an overestimation. After revisiting the JWST observations of the "record-breaking" black hole, astronomers confirmed that it is not extreme after all. In fact, heavy dust obscured the black hole, leading to incorrect calculations, the researchers found. In an accreting black hole, the infalling material is compressed and heated, causing it to emit high-energy radiation such as X-rays that push material away. The amount of matter a black hole can consume is governed by the Eddington limit, which defines the maximum luminosity at which the outward radiation pressure balances the black hole's gravitational pull. This limit depends directly on the black hole's mass — the higher the mass, the higher the Eddington limit. When the radiation pressure becomes high enough to overpower gravity, the black hole stops accreting matter and thus limits how brightly it shines. However, under certain conditions, a black hole can continue to accrete matter beyond this limit — a process known as super-Eddington accretion. The observations from last year suggested that LID-568 was undergoing super-Eddington accretion at nearly 40 times greater than expected. LID-568 existed just 1.5 billion years after the Big Bang — which is not enough time for this black hole to have grown this big. As a result, the astronomers speculated that such rapid super-Eddington accretion could provide a convincing explanation for the formation of supermassive black holes with unimaginably high masses in the early universe. But in the new research, published April 4 in The Astrophysical Journal, astronomers found that LID-568 is feeding at a rate consistent with the Eddington limit — and the mistake was caused by dust. The reason for the initial miscalculation about the black hole's hunger is because dust absorbs and scatters light, which significantly dims the light that reaches us from a black hole. "For a heavily dust-obscured object like LID-568, it is very important that dust extinction is corrected properly," said study co-author Myungshin Im, director of the Seoul National University Astronomy Research Center told Live Science in an email. If this effect is not properly accounted for, it can lead to inaccurate calculations of the black hole's mass, which, in turn, affects the Eddington limit associated with it. Im explained that, in the team's study, the researchers measured the black hole's mass using infrared light from the gas around it. Infrared radiation is much less affected by dust than optical light, which was used in the previous study for black hole mass measurement. This different approach allowed them to calculate the black hole's mass to be just under a billion solar masses — about 40 times greater than the previous estimate. Using this revised black hole mass, the Eddington luminosity was recalculated. Overall, the observed luminosity closely matched the Eddington limit. Therefore, the black hole was not in the super-Eddington phase when it was observed, the team concluded. It was just clouded by dust. RELATED STORIES —Newly 'awakened' black hole is releasing 100 times more energy than scientists have ever seen before —Incredible photo shows supermassive black hole blowing a jet of matter into interstellar space —Black holes can destroy planets — but they can also lead us to thriving alien worlds. Here's how. Consequently, LID-568's current feeding habits cannot be attributed to the growth of supermassive black holes, Im said. Astronomers have been aware of this issue in the case of distant galaxies and usually apply corrections for dust extinction in their measurements. However, for "active galactic nuclei" (AGN) — which contain actively feeding black holes at their centers that dominate the AGN's brightness and are surrounded by complex dust environments — "dust extinction correction has not been thoroughly applied yet," Im said. This means the masses of other black holes may have been measured incorrectly, leading to misinterpretations of their properties. The team's approach could lead to a better understanding of dust-obscured black holes in a new class of galaxies called "little red dots," which were recently discovered through JWST observations, the team explained in their paper.
Yahoo
23-04-2025
- Science
- Yahoo
Astronomers Confirm First Known Rogue Black Hole, And It's Wandering Our Galaxy
The universe is big, weird, and filled with unexpected things. It's the reason we send space probes to far reaches of our solar system and into deep space, it's the reason we build telescopes, and it's the reason we send astronauts hurdling into the abyss. In the pilot episode of Farscape (streaming now on Peacock), astronaut John Crichton hops aboard an experimental spacecraft designed to use Earth's gravity to slingshot into deep space. He's hoping to press the boundaries of human exploration, and he succeeds, but not how he expected. On his whirlwind trip around the planet, Crichton gets caught up in a wandering wormhole and transported to the far edge of the galaxy. Now, in the real world, astronomers have confirmed the existence of another wandering monstrosity, a rogue black hole cruising through our very own Milky Way Galaxy. In 2022 a team of astronomers detected what they thought might be a wandering black hole about 5,000 light-years from here, in the constellation Sagittarius. Those early observations suggested an object with incredible mass, but astronomers couldn't confidently say what it was. Some thought it was a stellar-mass black hole, while others thought it might be a less massive neutron star. More recent observations using the Hubble Space Telescope confirm that it must be a black hole, the first wandering stellar-mass black hole ever discovered. The discovery was published in The Astrophysical Journal. Prior to the discovery, every known black hole was gravitationally associated with a galaxy, a star cluster, or some other massive and visible object or objects. That's sort of the nature of hunting for black holes. By their nature, black holes don't release any light and can't be seen through traditional observing techniques. Instead, astronomers find and study black holes by looking for the gravitational influence they exert on their neighbors or by looking at the hot, fast matter orbiting around a black hole's event horizon. Black holes are just easier to find when they have a galaxy spinning around them. Astronomers have predicted that rogue black holes should exist, but because they have the ultimate in stealth technology, they can slink through the cosmos largely undetected. But they can't hide their gravity! The first hint of a rogue black hole came when it passed in front of a dim background star in 2011. Black holes have so much gravity that they visibly warp the space around them. When one passes in front of another object, like a background star or galaxy, the bent space can act like a lens, magnifying the light behind it. Astronomers also noted that the magnified background star is shifting positions as a result of its close brush with the object. Astronomers can't see a black hole, but they can see the lensing effect and the gravitational pull on passing stars. The new study is based on recent observations using the Hubble Space Telescope in 2021 and 2022, in addition to archival observations taken between 2011 and 2017. With the new data, astronomers calculate that the object is about seven times the mass of the Sun, putting it firmly in stellar-mass black hole territory. If we know there's one wandering black hole so close to us in our own galaxy, then there are almost certainly others. Astronomers estimate there may be as many as 100 million isolated black holes in our galaxy alone. Fortunately for us, space is big and it's unlikely any of them will come our way anytime soon. Explore the cosmos for yourself in Farscape, .
