The Universe is assumed to be around 13.8 billion years old, but new calculations suggest it could be younger than that.

This artists impression shows the evolution of the Universe beginning with the Big Bang on the left followed by the appearance of the Cosmic Microwave Background. The formation of the first stars ends the cosmic dark ages, followed by the formation of galaxies. Image credit: M. Weiss / Harvard-Smithsonian Center for Astrophysics.

Approaches to date the Big Bang, which gave birth to the Universe, rely on mathematics and computational modeling, using distance estimates of the oldest stars, the behavior of galaxies and the rate of the Universes expansion.

The idea is to compute how long it would take all objects to return to the beginning.

A key calculation for dating is the Hubbles constant, named after Edwin Hubble who first calculated the Universes expansion rate in 1929.

Another recent technique uses observations of the Cosmic Microwave Background (CMB), the oldest light in the Universe.

These methods reach different conclusions, said University of Oregons Professor James Schombert, lead author of the study.

Professor Schombert and his colleagues unveil a new approach that recalibrates a distance-measuring tool known as the baryonic Tully-Fisher relation independently of Hubbles constant.

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, Professor Schombert said.

The astronomers recalculated the Tully-Fisher approach, using accurately defined distances in a linear computation of the 50 galaxies as guides for measuring the distances of 95 other galaxies.

The Universe is ruled by a series of mathematical patterns expressed in equations, Professor Schombert said.

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.

The approach determines the Hubbles constant at 75.1 kilometers per second per megaparsec (km/s/Mpc), give or take 2.3.

All Hubbles constant values lower than 70 km/s/Mpc can be ruled out with 95% degree of confidence, the researchers said.

Traditionally used measuring techniques over the past 50 years have set the value at 75 km/s/Mpc, but CMB computes a rate of 67 km/s/Mpc.

The CMB technique, while using different assumptions and computer simulations, should still arrive at the same estimate.

Calculations drawn from observations of NASAs Wilkinson Microwave Anisotropy Probe (WAMP) in 2013 put the age of the Universe at 13.77 billion years, which, for the moment, represents the standard model of Big Bang cosmology.

The differing Hubbles constant values from the various techniques generally estimate the Universes age at between 11.4 billion and 14.5 billion years.

The new study, based in part on observations made with NASAs Spitzer Space Telescope, adds a new element to how calculations to reach Hubbles constant can be set, by introducing a purely empirical method, using direct observations, to determine the distance to galaxies.

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, Professor Schombert said.

The results were published in the Astronomical Journal.

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James Schombert et al. 2020. Using the Baryonic Tully-Fisher Relation to Measure Ho. AJ 160, 71; doi: 10.3847/1538-3881/ab9d88

This article is based on text provided by the University of Oregon.

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