Latest news with #PavelKroupa
Yahoo
4 days ago
- General
- Yahoo
The Big Bang's Glowing 'Echo' May Be Something Else Entirely
Part of the reason scientists have settled on the Big Bang theory as the best explanation of how the Universe came into being is because of an 'afterglow' it emits – but a new study suggests we may need to rethink the source of this faint radiation. Technically, this afterglow is known as Cosmic Microwave Background (CMB) radiation, and it's been traveling through space for more than 13 billion years, since soon after the Big Bang first went bang. It can be picked up by our most advanced telescopes. Now, researchers from Nanjing University in China and the University of Bonn in Germany have run calculations suggesting we've overestimated the strength of the CMB. In fact, it might not even be there at all. The rocking of the cosmological boat, as it were, is driven by new evidence of early-type galaxies (ETGs). Recent data from the James Webb Space Telescope suggests these ETGs might account for some or even all of the CMB, depending on the simulation used. "Our results are a problem for the standard model of cosmology," says physicist Pavel Kroupa, from the University of Bonn. "It might be necessary to rewrite the history of the Universe, at least in part." Scientists already know plenty about ETGs, which are usually elliptical in shape. What's new is that recent studies, and this latest interpretation of them, point to these types of galaxies having formed even earlier than previous models accounted for. If that timeline shifts, then so does the pattern of radiation spreading out across the Universe. In simple terms, the Universe may have moved through its initial phase of gas surges and galaxy formation quicker than we imagined. "The Universe has been expanding since the Big Bang, like dough that is rising," says Kroupa. "This means that the distance between galaxies is increasing constantly." "We have measured how far apart elliptical galaxies are from one another today. Using this data and taking into account the characteristics of this group of galaxies, we were then able to use the speed of expansion to determine when they first formed." This earlier estimate for the formation of these ETGs means that their brightness could emerge "as a non-negligible source of CMB foreground contamination", the researchers write. We should bear in mind that this research is still in its preliminary stages. It's not time yet to start pulping scientific textbooks – or whatever the modern equivalent is. Rewriting Wikipedia, perhaps? But this research certainly raises some big questions. Given the almost unimaginable timescales and distances involved, it's difficult for astrophysicists to always be precise. The researchers suggest anywhere from 1.4 percent to 100 percent of the CMB could be explained by their new models. What's certain is that as our space telescopes and analysis systems get more sophisticated, we're learning more about the surrounding Universe than ever before – and that in turn means some previous assumptions may have to be readjusted, including those about the very formation of the Universe itself. "In the view of the results documented here, it may become necessary to consider [other] cosmological models," write the researchers in their published paper. The research has been published in Nuclear Physics B. A Serious Threat May Be Lurking in The Orbit of Venus, Says Study We Now Know What Switched The Lights on at The Dawn of Time Light Travels Across The Universe Without Losing Energy. But How?
Yahoo
25-03-2025
- Science
- Yahoo
Scientists Intrigued by "Star Grinder" Pulverizing Entire Star Systems in Our Galaxy
Astronomers suggest there's a giant "star grinder" lurking at the center of the Milky Way, churning up potentially tens of thousands of star systems that are unfortunate enough to get too close. As detailed in a new paper to be published in the journal Astronomy & Astrophysics and first spotted by Universe Today, astronomers in the Czech Republic and Germany suggest that B-type stars, which are only a few times the mass of the Sun, as well as much heavier O-type stars, are being blended up with tens of thousands of smaller black holes near Sagittarius A*, the supermassive black hole at the center of our galaxy. According to the theory, only the smaller and older B-type stars can survive this ordeal, with the much more massive O-type stars succumbing to their early demise less than five million years into their lifespan — and turning into more small black holes in the maelstrom instead. The research could force us to reconsider what we know about the violent events happening at the center of our galaxy — a brutal cycle of life and death, right at the core of the Milky Way. The research could also explain an observation that has puzzled astronomers for years. Within less than a tenth of a light-year from Sagittarius*, O-type stars are nowhere to be found. B-type stars, however, are the predominant type so close to the giant black hole, many of which have been observed to be ejected from the center at extremely fast speeds. "The smaller B-stars can survive much longer, in fact for some 50 million years," said lead author and Charles University, Czechia, astronomy PhD Jaroslav Haas in a statement. "This explains why the heavy O-type stars are missing at distances smaller than about one-tenth of a light year from SgrA*, with only B-stars surviving there." "These results give us an entirely new understanding of the immediate surroundings of the central super-massive black hole," explained coauthor and Charles University astrophysicist Pavel Kroupa. Haas and his colleagues found that the density of black holes actually increases as you move away from the galactic center, before dropping again at a certain distance. Such a density profile is a "result of the complicated dynamical processes near the central super-massive black hole and our results will allow us to perform new computer simulations to better understand these," explained coauthor and head of the Charles University Astronomical Institute Ladislav Šubr. The researchers are now excited to better understand the "violent pack of thousands of black holes at the center of our Galaxy that is continuously destroying the stars down there," according to coauthor and Charles University astronomer Myank Singhal. More on Sagittarius A*: Scientists Capture Amazing Image of Black Hole at Center of Our Galaxy
