The Biggest Controversy in Cosmology Just Got Bigger

(With immoderate method, the physicists indispensable deduce the implicit region of astatine slightest 1 “anchor” postulation successful bid to calibrate the full scale. For their anchor, Riess, Freedman and different groups usage an antithetic adjacent postulation whose implicit region has been determined geometrically done a parallax-like effect.)

Using TRGBs arsenic region indicators is much analyzable than utilizing Cepheids, however. McQuinn and her colleagues utilized 9 of the Webb telescope’s wavelength filters to understand precisely however their brightness depends connected their color.

Astronomers are besides opening to crook to a caller region indicator: carbon-rich elephantine stars that beryllium to what’s called the J-region asymptotic elephantine subdivision (JAGB). These stars besides beryllium distant from a galaxy’s agleam disk and emit a batch of infrared light. The exertion to observe them astatine large distances wasn’t capable until the Webb era, said Freedman’s postgraduate pupil Abigail Lee.

Freedman and her squad applied for Webb scope clip to observe TRGBs and JAGBs on with the much established region indicators, the Cepheids, successful 11 galaxies. “I americium a beardown proponent of antithetic methods,” she said.

An Evaporating Solution

On March 13, 2024, Freedman, Lee, and the remainder of their squad sat astir a array successful Chicago to uncover what they had been hiding from themselves. Over the erstwhile months, they had divided into 3 groups. Each was tasked with measuring the region to the 11 galaxies successful their survey utilizing 1 of 3 methods: Cepheids, TRGBs, oregon JAGBs. The galaxies besides hosted the applicable kinds of supernovas, truthful their distances could calibrate the distances of supernovas successful galore much galaxies farther away. How accelerated these farther galaxies are receding from america (which is easy work disconnected from their color) divided by their distances gives H₀.

The 3 groups had calculated their region measurements with a unsocial random offset added to the data. When they met successful person, they removed each of the offsets and compared the results.

All 3 methods gave akin distances, wrong 3 percent uncertainty. It was “sort of jaw-dropping,” Freedman said. The squad calculated 3 H₀ values, 1 for each region indicator. All came wrong scope of the theoretical prediction of 67.4.

At that moment, they appeared to person erased the Hubble tension. But erstwhile they dug into the investigation to constitute up the results, they recovered problems.

The JAGB investigation was fine, but the different 2 were off. The squad noticed that determination were ample mistake bars connected the TRGB measurement. They tried to shrink them by including much TGRBs. But erstwhile they did so, they recovered that the region to the galaxies was smaller than they archetypal thought. The alteration yielded a larger H₀ value.

In the Cepheid analysis, Freedman’s squad uncovered an error: In astir fractional the Cepheids, the correction for crowding had been applied twice. Fixing that importantly accrued the resulting H₀ value. It “brought america much into statement with Adam [Riess], which ought to marque him a small happier,” Freedman said. The Hubble hostility was resurrected.