In an epic cosmology clash, rival scientists begin to find common ground
The biggest clash in cosmology might be inching closer to resolution, thanks to the James Webb Space Telescope.
Scientists disagree over the universe’s expansion rate, known as the Hubble constant. There are two main methods for measuring it — one based on exploding stars called supernovas and the other on the universe’s oldest light, the cosmic microwave background. The two techniques have been in conflict for a decade, in what’s known as the “Hubble tension.” If this tension is real, and not the result of an error in one of the measurements, it would demand a drastic shift in how scientists understand the universe.
New papers published by two of the central players are raising hopes that additional observations from the James Webb Space Telescope, or JWST, of certain types of stars and supernovas could solve the question of whether the discord is real, once and for all.
The two teams disagree about whether that tension exists at all. One team says there’s no strong evidence for the Hubble tension from the JWST data. But the other group says the JWST data strengthen the case that the two types of measurements are in conflict. “I’m even more intrigued by the Hubble tension,” says cosmologist Adam Riess of Johns Hopkins University, leader of one of the teams.
The different camps are finally seeing eye to eye on one piece of their measurements: distances to nearby galaxies, which are necessary to deduce the expansion rate of the universe from supernovas. “This is really new — we’re agreeing on distances, and that’s real progress,” says cosmologist Wendy Freedman of the University of Chicago, who leads the other team. [Continue reading…]