Latest news with #VikramRavi
Yahoo
8 hours ago
- Science
- Yahoo
What Astronomers Just Discovered Between Galaxies Changes Everything
For decades, scientists have known that a massive chunk of the universe's ordinary matter was missing. Not dark matter, the elusive substance that doesn't interact with light, but regular, everyday matter made of atoms. And now, thanks to a brilliant use of cosmic radio signals, that mystery may finally be solved. In a new study published in Nature Astronomy, astronomers used fast radio bursts (FRBs)—brief, millisecond-long blasts of energy from deep space—to detect where all that missing matter was hiding: in the vast stretches between galaxies, known as the intergalactic medium. These FRBs are powerful. Though short-lived, they emit as much energy in one burst as the sun does in 30 years. When they pass through space, they act like cosmic flashlights, lighting up the otherwise invisible gas that floats between galaxies. The team measured how the light from 69 FRBs slowed as it moved through this matter, allowing them to "weigh" the fog they passed through. "It's like we're seeing the shadow of all the baryons," explained Caltech assistant professor Vikram Ravi, using the scientific term for this ordinary matter. "With FRBs as the backlight, we now know roughly where the rest of the matter in the universe is hiding." The results show about 76 percent of the universe's baryonic matter exists in this intergalactic fog. Meanwhile, 15 percent of the baryonic matter surrounds galaxies in halos and just 9 percent resides inside the galaxies themselves. This breakthrough was made possible by telescopes like Caltech's Deep Synoptic Array and Australia's Square Kilometre Array Pathfinder, which helped localize the FRBs' origins. Caltech's upcoming DSA-2000 radio telescope, set to detect 10,000 FRBs per year, could be the key to even deeper cosmological insights. For astronomers, it's a milestone moment—one that brings us closer to understanding not just where we come from, but how the universe is truly structured. What Astronomers Just Discovered Between Galaxies Changes Everything first appeared on Men's Journal on Jun 17, 2025
Yahoo
a day ago
- Science
- Yahoo
Invisible no more: Scientists map 76% of ordinary matter lost between galaxies
For years, the universe held onto a secret that left cosmologists half of the universe's ordinary matter, responsible for building everything from protons and stars to planets and people, has remained elusive due to its diffuse nature. Scientists had considered it 'missing'—until now.' Now, in a breakthrough study, astronomers from Caltech and the Center for Astrophysics | Harvard & Smithsonian (CfA) have managed to directly detect this missing matter using fast radio bursts (FRBs)—brief, powerful flashes of radio waves originating from distant galaxies. These cosmic signals, lasting just milliseconds, serve as precise probes, lighting up the otherwise invisible intergalactic medium. As these FRBs travel billions of light-years to reach Earth, they pass through clouds of ionized gas between galaxies. The radio waves slow down ever so slightly depending on how much matter they encounter along the way. By measuring this delay, known as dispersion, scientists can calculate the amount of invisible matter in the FRBs' path. "The FRBs shine through the fog of the intergalactic medium, and by precisely measuring how the light slows down, we can weigh that fog, even when it's too faint to see," says Liam Connor, assistant professor at Harvard and lead author of the study. The study analyzed 69 well-localized FRBs, each with a host galaxy and known distance. One of the FRBs studied, dubbed FRB 20230521B, is located a staggering 9.1 billion light-years away, making it the most distant fast radio burst ever recorded. Although astronomers have detected over a thousand FRBs to date, only around a hundred have been accurately traced back to their host galaxies. This localization is crucial, as knowing both the origin and distance of an FRB is essential for using it to map the matter it passed through, making these select few key to the current study. Of these, 39 were discovered using the Deep Synoptic Array (DSA)-110, a network of 110 radio antennas in California designed specifically to detect and pinpoint FRBs. The remaining FRBs came from global observatories, including Australia's Square Kilometre Array Pathfinder. Instruments at Hawaii's W. M. Keck Observatory and the Palomar Observatory near San Diego helped determine the distance to each FRB's host galaxy. Their findings confirm that roughly 76 percent of ordinary matter resides in the intergalactic medium, thinly spread across space. Another 15 percent lies in gaseous halos surrounding galaxies, while only a small fraction is found inside galaxies themselves, in stars, or cold galactic gas."It's like we're seeing the shadow of all the baryons, with FRBs as the backlight," said Vikram Ravi, assistant professor of astronomy at Caltech. "If you see a person in front of you, you can find out a lot about them. But if you just see their shadow, you still know that they're there and roughly how big they are." This distribution of matter aligns with predictions made by advanced cosmological simulations but has never been confirmed observationally—until now. The findings also open new avenues for probing fundamental physics. For instance, they may help determine the mass of subatomic particles called neutrinos. While the standard model of particle physics assumes neutrinos have no mass, real-world observations suggest otherwise. Knowing their precise mass could unlock physics beyond current theories. According to Ravi, this is just the beginning for FRBs in cosmology. A new project, Caltech's DSA-2000 radio telescope, currently in development for the Nevada desert, is expected to localize up to 10,000 FRBs each year—dramatically expanding their role in probing the universe's structure. The study, published in Nature Astronomy, was funded by the National Science Foundation.
