Latest news with #EventHorizonTelescope
Gizmodo
2 days ago
- General
- Gizmodo
Scientists Are Creeping Closer to Colorized Black Hole Images
Black holes are infamous for being invisible. But thanks to a new technique from the Event Horizon Telescope (EHT) team, we're about to start seeing them in color. Astronomers have figured out a way to observe the radio sky in multiple frequencies at once, allowing them to create full-color images of supermassive black holes. The breakthrough is built on a technique called frequency phase transfer, which lets scientists correct for atmospheric interference in real time across multiple radio bands. In plain English: They've basically figured out how to give radio telescopes a multi-color vision upgrade. Sara Issaoun, a researcher at the Center for Astrophysics | Harvard & Smithsonian, led the team, whose research was recently published in The Astronomical Journal. The Event Horizon Telescope (EHT) stunned the world in 2019 with the first image of a black hole—M87*, followed in 2022 by Sagittarius A*, the supermassive black hole at our galaxy's center. Now, scientists are planning a $300 million space-based successor mission, the Event Horizon Explorer, designed to sharpen those images tenfold and reveal the elusive photon rings that may confirm black hole spin and push the limits of general relativity. Meanwhile, some researchers have challenged aspects of the original Sgr A* image, proposing that its accretion disk may be more elongated than ring-like—an open question future observations may resolve. Similar to how our eyes take in visible light's various wavelengths and interpret them as a range of colors, radio telescopes capture slices of invisible radio light in specific frequency bands. Stitch enough of those slices together and you get something like a color image—just not in the visible spectrum. But until now, most radio telescopes could only observe one frequency band at a time. That's fine when astronomers' target is a distant galaxy that appears sedentary against the cosmos. But if scientists are trying to image a rapidly spinning black hole spewing relativistic jets, or wobbling from gravitational forces, the radio data can't be captured in a single image. The object simply moves so fast that multiple exposures can't be layered in a coherent way. Enter frequency phase transfer. As reported in Universe Today, the team was able to track atmospheric distortions in their observations at one wavelength and sharpen the image in a different wavelength. (Correcting for atmospheric distortion is a regular problem for Earth-based observatories, but new technologies are allowing telescopes to overcome this longstanding hurdle in ground-based astronomy). The team's new black hole imaging method is still experimental, but the proof-of-concept means we're on the cusp of getting sharper, truer images of the most extreme objects in the universe. Next-gen observatories like the EHT and Black Hole Explorer (BHEX) are already gearing up to use this method, bringing us one step closer to seeing a black hole in all its violent and vivid brilliance.
Yahoo
3 days ago
- Science
- Yahoo
World's first color images of black holes are on their way
When you buy through links on our articles, Future and its syndication partners may earn a commission. Astronomers with the Event Horizon Telescope have developed a new way to observe the radio sky at multiple frequencies, and it means we will soon be able to capture color images of supermassive black holes. Color is an interesting thing. In physics, we can say the color of light is defined by its frequency or wavelength. The longer the wavelength, or the lower the frequency, the more toward the red end of the spectrum light is. Move toward the blue end, and the wavelengths get shorter and the frequencies higher. Each frequency or wavelength has its own unique color. Of course, we don't see it that way. Our eyes see color with three different types of cones in our retina, sensitive to red, green, and blue light frequencies. Our minds then use this data to create a color image. Digital cameras work similarly. They have sensors that capture red, green, and blue light. Your computer screen then uses red, green, and blue pixels, which tricks our brain into seeing a color image. While we can't see radio light, radio telescopes can see colors, known as bands. A detector can capture a narrow range of frequencies, known as a frequency band, which is similar to the way optical detectors capture colors. By observing the radio sky at different frequency bands, astronomers can create a "color" image. Related: The rarest black holes in the universe may be 'wandering' our galaxy — but scientists don't know how to detect them But this is not without its problems. Most radio telescopes can only observe one band at a time. So astronomers have to observe an object multiple times at different bands to create a color image. For many objects, this is perfectly fine, but for fast-changing objects or objects with a small apparent size, it doesn't work. The image can change so quickly that you can't layer images together. Imagine if your phone camera took a tenth of a second to capture each color of an image. It would be fine for a landscape photo or selfie, but for an action shot the different images wouldn't line up. RELATED STORIES —Physicists create 'black hole bomb' for first time on Earth, validating decades-old theory —James Webb Space Telescope finds a wild black hole growth spurt in galaxies at 'cosmic noon' —Has the James Webb Space Telescope discovered a 'missing' supermassive black hole? (video) This is where this new method comes in. The team used a method known as frequency phase transfer (FPT) to overcome atmospheric distortions of radio light. By observing the radio sky at the 3mm wavelength, the team can track how the atmosphere distorts light. This is similar to the way optical telescopes use a laser to track atmospheric changes. The team demonstrated how they can observe the sky at both a 3mm and 1mm wavelength at the same time and use that to correct and sharpen the image gathered by the 1mm wavelength. By correcting for atmospheric distortion in this way, radio astronomers could capture successive images at different radio bands, then correct them all to create a high-resolution color image. This method is still in its early stages, and this latest study is just a demonstration of the technique. But it proves the method can work. So future projects such as the next-generation EHT (ngEHT) and the Black Hole Explorer (BHEX) will be able to build on this method. And that means we will be able to see black holes live and in color. The original version of this article was published on Universe Today.
Yahoo
25-02-2025
- Science
- Yahoo
9 Misconceptions You Probably Have About Black Holes
Black holes are some of the weirdest, most fascinating things in the universe, but thanks to sci-fi and pop culture, a lot of what people think they know about them isn't actually true. Scientists have been studying black holes for decades, and while there's still plenty we don't fully understand, we do know that some of the most common ideas about them are way off. A lot of people think black holes just roam around space, sucking up everything like some kind of cosmic Roomba. But that's not how they work. Their gravity isn't magical. It follows the same rules as any other massive object, like a planet or a star. Things can actually orbit a black hole just fine, as long as they stay at a safe distance. The real danger zone is the event horizon. Once something crosses that point, there's no coming back. But unless you're already far too close, a black hole isn't going to randomly pull you in. You'd have to drift toward it, just like you would with any other strong gravitational force. Black holes don't give off light themselves, but that doesn't mean they're impossible to see. Instead of looking for the black hole itself, scientists watch how it affects the surrounding matter. For example, a black hole's gravity pulls in gas and dust, creating a swirling accretion disk that gets very hot and glows brightly. That's often the first clue that a black hole is there. In 2019, astronomers actually managed to photograph a black hole's 'shadow' using the Event Horizon Telescope. It's not the black hole itself, but the glowing material around it and the way light bends near the event horizon. Black holes aren't one-size-fits-all. They come in different sizes, depending on how they formed. Here's what we know (or theorize, at least) at the moment: Stellar-mass black holes are the 'regular' kind, formed when a massive star collapses. They're a up to a few dozen times the mass of the Sun. Intermediate-mass black holes are the middleweights, ranging from hundreds to thousands of solar masses. Scientists are still trying to figure out how they form. Supermassive black holes are the monsters lurking at the centers of galaxies, millions or even billions of times the mass of the Sun. Sagittarius A*, the one at the center of our Milky Way, is one of these. Primordial black holes are purely theoretical (for now). If they exist, they'd be tiny, maybe even as small as an atom, formed in the early universe. Not every star gets the dramatic black hole ending. Only the biggest ones that are about 20 times the mass of the Sun or more have enough gravity to collapse into a black hole when they die. Smaller stars, like our Sun, have a much quieter fate. When they run out of fuel, they shed their outer layers and leave behind a white dwarf, a super-dense but not quite black-hole-level core. Slightly bigger stars might collapse into neutron stars, which are insanely dense but still not black holes. Falling into a black hole sounds like an instant, brutal death, but it actually depends on the size of the black hole. In a stellar-mass black hole (the smaller kind), things would go bad fast. Gravity changes so sharply near the event horizon that you'd be stretched into a thin strand (a phenomenon appropriately named spaghettification) long before you even reach the center. But if you fell into a supermassive black hole like Sagittarius A, the one in the middle of our galaxy, you might not even notice when you crossed the event horizon. The gravitational pull changes more gradually, so you wouldn't get stretched out right away. That said, you'd still die. It's true that once you cross a black hole's event horizon, there's no coming back. Not even light can escape. But that doesn't mean black holes last forever. Thanks to a weird quantum effect called Hawking radiation (named after Stephen Hawking), black holes slowly lose energy over time. This means they actually shrink incredibly slowly. Given enough time, like far longer than the current age of the universe, a black hole could completely evaporate. So while nothing escapes from inside, black holes themselves don't stick around forever. Black holes aren't anchored in space. They can move, just like stars and planets, sometimes at intense speeds. Most black holes stay put, like the supermassive black hole at the center of our galaxy. But some, called rogue black holes, drift through space. They can get kicked out of their original locations by gravitational tugs from other objects or even from collisions with other black holes. Despite the name, black holes aren't actually holes or empty voids. They're super-dense objects with a ton of mass and gravity, just like stars or planets, but way more extreme than anything we're used to. Black holes form when a massive star collapses in on itself, cramming all its mass into an unbelievably small space. This creates a gravitational pull so strong that nothing can escape past the event horizon. Not even light. So, a black hole isn't some cosmic hole. It's more like a super-packed object that bends space and time in a way that makes it impossible to escape once you get too close. Some people worry that the Large Hadron Collider, the world's most powerful particle accelerator built to smash protons together at nearly the speed of light, might accidentally create a black hole that swallows the planet. But there's really no danger. This idea is more science fiction than science. The idea comes from the fact that high-energy particle collisions, like the ones in the LHC, could theoretically produce tiny black holes. But even if that happened (which isn't certain), these black holes would be microscopic and would disappear almost instantly thanks to Hawking radiation. They wouldn't stick around long enough to do any damage. Plus, nature has been running its own version of the LHC for billions of years. Cosmic rays, which are high-energy particles from space, smash into Earth's atmosphere all the time with way more energy than anything we can create in a lab. If those collisions were dangerous, we wouldn't be here right now. While black holes are obviously very real, the idea of a man-made one destroying Earth just doesn't line up with actual physics… yet. Black holes do have mind-bending properties, but they're not what sci-fi makes them out to be. We now have real images of black holes, we know they can move through space, and we even understand how they can slowly evaporate over time. The reality of black holes is much more fascinating than fiction.
