Approaches to date the Big Bang, depend on mathematics and computational modeling. The model uses distance estimates of the oldest stars, the behavior of galaxies, and the rate of the universe’s expansion. The idea is to compute how long it would take all objects to return to the beginning.

Recent methodologies use observations of leftover radiation from the Big Bang. It maps bumps and wiggles in spacetime and reflects conditions in the early universe as set by Hubble’s constant.

Now, astronomers from the University of Oregon have unveiled another methodology that recalibrates a distance-estimating tool known as the baryonic Tully-Fisher relation independently of Hubble’s constant.

James Schombert, a professor of physics at the UO, said, *“The distance scale problem, as it is known, is incredibly difficult because the distances to galaxies are vast and the signposts for their distances are faint and hard to calibrate.”*

Astronomers recalculated the Tully-Fisher approach by defining distances in a linear computation of the 50 galaxies as guides for measuring the distances of 95 other galaxies.

Schombert said,* “The universe, he noted, is ruled by a series of mathematical patterns expressed in equations. The new approach more accurately accounts for the mass and rotational curves of galaxies to turn those equations into numbers like age and expansion rate.”*

This new approach determines the Hubble’s constantâ€”the universe’s expansion rateâ€”at 75.1 kilometers per second per megaparsec, give or take 2.3. A megaparsec, a standard unit of space-related measurements, is equal to one million parsecs. A parsec is about 3.3 light-years.

The team noted, *“All Hubble’s constant values lower than 70 can be ruled out with a 95 percent degree of confidence.”*

Schombert said, *“Traditionally used measuring techniques over the past 50 years, have set the value at 75, but CMB computes a rate of 67. The CMB technique, while using different assumptions and computer simulations, should still arrive at the same estimate.”*

*“The tension in the field occurs from the fact that it does not. This difference is well outside the observational errors and produced a great deal of friction in the cosmological community.”*

*“Our resulting value is on the high side of the different schools of cosmology, signaling that our understanding of the physics of the universe is incomplete with the hope of new physics in the future.”*

##### Journal Reference:

- James Schombert et al., Using the Baryonic Tullyâ€“Fisher Relation to Measure H o, The Astronomical Journal (2020). DOI: 10.3847/1538-3881/ab9d88