Our Universe is Much Younger Than Initially Thought

Scientists initially thought the universe was 13.8 billion years old. New measurements suggest its much younger. 

Until not long ago, it was believed that our universe was 13.8 billion years old. However, a new study has found that its likely much younger than that.

According to a study published in the Astronomical Journal, the universe we live i is more likely around 12.6 billion years old, which means its much younger than initially thought.

But how can you know how old the universe is? We can find out its age by measuring galaxies and their distance from Earth.

Observable measurements in the distance from Earth of 50 galaxies were used by the University of Oregon physicist Jim Schombert and his team to fit a 90-year computational tool called the Hubble constant to measure the expansion of the cosmos.

Dating the Big Bang, which eventually gave birth to our universe, has been based on mathematics and computational modeling, using distance estimates to some of the oldest stars in the cosmos, the behavior of galaxies, and the rate of expansion of the universe.

The idea is to calculate how long it would take for all objects in the universe to travel back to the beginning, right before the moment when the Big Bang took place.

A key calculation in all of this is the Hubble constant, named after Edwin Hubble, who first calculated the rate of expansion of the universe in 1929.

A more recent technique uses observations of surplus radiation from the Big Bang.

It maps echoes in space-time, known as the cosmic microwave background, and reflects conditions in the early universe as established by the Hubble constant.

The science for such research, Schombert said, is governed by mathematical patterns expressed in equations that often reach different conclusions.

The age of the universe, under different scenarios, varies from 12,000 million to 14,500 million years.

“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,” Schombert said.

A view of the map of the cosmic microwave background across the sky. Image Credit: ESA and the Planck Collaboration.
A view of the map of the cosmic microwave background across the sky. Image Credit: ESA and the Planck Collaboration.

To fine-tune the age of the universe, Schombert and his colleagues used a new approach, recalibrating a distance measurement tool known as the Tully-Fisher baryonic ratio regardless of the Hubble constant.

They took the distances of 50 galaxies, as determined in part with the help of the Spitzer Space Telescope, and used that data to estimate the distances of 95 other galaxies.

This approach, Schombert said, better explains the mass and rotation curves of galaxies than the data used to build previous equations.

Schombert’s team established the Hubble constant at 75.1 kilometers per second per megaparsec, plus or minus 2.3. A megaparsec, a common unit of space-related measurements, equals 1 million parsecs.

A parsec is approximately 3.3 light-years.

All Hubble constant values ​​less than 70, his team wrote, can be discarded with 95 percent confidence.

Traditional measurement techniques for the past 50 years have set the value to 75, while the cosmic microwave background approach calculates a rate of 67.

The techniques, Schombert said, should still arrive at the same estimate.

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

Calculations from observations of NASA’s Wilkinson microwave anisotropy probe in 2013 put the age of the universe at 13.77 billion years, which, for the time being, represents the standard model of Big Bang cosmology.

Via
University of Oregon
Source
The Astronomical Journal
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