On Thursday, astronomers who are conducting what they describe as the biggest and most precise survey yet of the history of the universe announced that they might have discovered a major flaw in their understanding of dark energy, the mysterious force that is accelerating the expansion of the cosmos.
The keywords are “might” and “could”. The new finding has about a 1-in-400 chance of being a statistical fluke, a degree of uncertainty called three sigma, which is far short of the gold standard for a discovery, called five sigma: 1 chance in 1.7 million. In the history of physics, even five-sigma events have evaporated when more data or better interpretations of the data emerged.
As artist’s impression of an asteroid orbiting close to the sun. The asteroid was found by the A Dark Energy Camera at the Cerro Tololo Inter-American Observatory in Chile.“It’s certainly more than a curiosity,” Palanque-Delabrouille said. “I would call it a hint. Yeah, it’s not yet evidence, but it’s interesting.”Wendy Freedman, an astrophysicist at the University of Chicago who has led efforts to measure the expansion of the universe, praised the new survey as “superb data”.
Dark energy took its place in the standard model of the universe known as LCDM, composed of 70 per cent dark energy , 25 per cent cold dark matter and 5 per cent atomic matter. So far that model has been bruised but not broken by the new James Webb Space Telescope. But what if dark energy were not constant as the cosmological model assumed?At issue is a parameter called w, which is a measure of the density, or vehemence, of the dark energy.