If you zoom out on the universe, beyond the level of planets, stars or galaxies, you will eventually see a vast, uniformly blotchy expanse with no notable features. At least, this has been the traditional view.
The principle that everything looks the same everywhere is a fundamental pillar of the Standard Model of cosmology, which aims to explain the Big Bang and how the universe has evolved in the 13.7 billion years since.
But this week a meeting of some of the world’s leading cosmologists will convene at the Royal Society in London to ask the question: What if this basic assumption is wrong?
The meeting comes after several high-profile astronomical observations have challenged the conventional view, according to Professor Subir Sarkar, a cosmologist at the University of Oxford and co-organizer of the meeting.
“We are using a model in cosmology that was first formulated in 1922,” he said. “We have great data, but the theoretical base is past its sell-by date. “More and more people are saying the same thing, and these are respected astronomers.”
This conference brings together some of the scientists behind recent anomalous discoveries. These include observations that suggest the universe is expanding more rapidly in some regions than others, signs of megastructures in the night sky, and evidence of cosmic flows – vast celestial rivers of material on scales that cannot be measured by conventional Cannot be easily accommodated within principles.
Dr. Nathan Seacrest of the U.S. Naval Observatory and government colleagues are presenting findings that raise the possibility that the universe is a little unbalanced. After analyzing a catalog of more than 1 million quasars (extremely luminous galactic cores), the team found that one hemisphere of the sky appears to host about 0.5% more sources than the other.
This may not seem like a big anomaly, but, according to the government, if confirmed it would undermine the premise of dark energy being thought to be a major component of the universe. “This would mean that two-thirds of the universe has disappeared,” Sarkar said.
Dr. Constantino Migkas, of Leiden University, will share findings that the Hubble constant – the rate at which the universe is expanding – appears to vary throughout space. “Our results add another problematic piece to the puzzle,” Migkas said. Locally, at least, this suggests that observations do not match the predictions of the Standard Model. “We can’t predict that everything is wrong throughout the universe,” he said.
Alexia Lopez, a PhD student at the University of Central Lancashire, has discovered cosmic megastructures called the Big Ring and the Giant Arch. These patterns detected by galaxies and galaxy clusters occur on a scale beyond which the universe should be smooth and effectively featureless.
“When we’re finding lists of structures that exceed this scale, are they challenging this assumption that is so fundamental in cosmology?” Lopez said. “Perhaps our standard model needs to be analyzed more critically.”
Sarkar suggests that belief in the Standard Model of Cosmology is so deeply ingrained that it counts as a “religion”. He said, “I find it frankly disturbing that this theory has not been checked,” although not everyone agrees with this characterization.
Professor George Efstathiou, an astrophysicist at the University of Cambridge, who is presenting a more skeptical view at the conference, said it was not true that the models had not been repeatedly questioned. “People accuse me of defending the model,” he said. “But they don’t realize how much time I’ve spent trying to prove it wrong. I completely disagree that this is some kind of groupthink.”
Efstathiou said that while intriguing, none of the discrepancies being presented were compelling enough to undermine the standard principles. “The question is: How good is the data?” He said. Claims of the imbalance of the universe, for example, may be due to the required use of multiple telescopes to observe different hemispheres of the sky, so that sifting through the data to look for patterns will inevitably turn up inconsistencies, he suggested. . He said, “The big circle in the sky, I certainly don’t believe.”
Professor Wendy Freedman, who is presenting the new findings from the James Webb Space Telescope, said: “There are all these fascinating threads here at different levels of significance. We need more exploration of where the standard model fails. I don’t think there’s any obvious thing that will stand the test of time.”
Such vigorous debate is welcome at the conference. “I’m expecting a vigorous discussion,” Sarkar said. “Let them come with whatever they’ve got.”