Scientists measuring the age of the universe with a new model are left stumped by discovery
A gravitational wave seems to have confirmed the age of the universe but with intrigue, say experts.
The study of one of the gravitational waves recorded in recent months has allowed estimating the age of the Universe, confirming previous calculations but with an intrigue factor.
The direct detection of gravitational waves from at least five sources during the last two years offers a spectacular confirmation of Einstein’s gravity and space-time model.
Astronomers also gathered information on the massive formation of stars, gamma ray bursts, neutron star characteristics and (for the first time) the verification of theoretical ideas about how very heavy elements such as gold are produced.
According to reports from the Smithsonian Astrophysical Observatory, astronomers used a single gravitational wave event—referred to as GW170817— to measure the age of our universe.
NGC4993, the galaxy hosting the gravitational wave event GW170817 that has been used to measure the age of the universe. Image Credit: ESA/NASA
Experts at the CfA (Harvard Smithsonian Center for Astrophysics), Peter Blanchard, Tarreneh Eftekhari, Victoria Villar and Peter Williams were members of a team of 1,314 scientists from around the globe who contributed to the detection of gravitational waves from a merging pair of binary neutron stars, followed by the detection of gamma-rays, and the identification of the origin of the cataclysm in a source in the galaxy NGC4993 detected in images taken with several delays in wavelengths from X-rays to radio.
Furthermore, analysis of the gravitational waves of the event suggests its intrinsic strength.
The observed force is smaller, which implies that the source is about 140 million light-years away.
Experts note that NGC4993, the host galaxy, has an outward velocity because of the expansion of the universe that can be measured from its spectral lines.
Knowing how far away it is and how fast the galaxy is moving allows scientists to calculate the time since the expansion began: aka the age of the universe: between 11,900 and 15,700 million years due to experimental uncertainties.
Scientists note how the age derived from this unique event is consistent with decades-old estimates of observations based on statistical methods that use two other sources: cosmic microwave background radiation (CMBR) and galaxy movements.
The first is based on the mapping of the very weak distribution of light that dates back about four hundred thousand years after the Big Bang; while the latter involves a statistical analysis of the distances and movements of tens of thousands of galaxies in relatively recent times.
The fact that a single gravitational wave even allowed the determination of the age of the cosmos is beyond remarkable and is not possible with every gravity wave detection. As noted by a statement by the cFa, in this case, there was an optical identification of the source (so that speed could be measured) and the source was not too distant or too weak.
With a large statistical sample of gravitational wave events of all types, the current range of values for age will be reduced, explain experts.
The Wow part
The new result is intriguing for many reasons. Despite the fact that both CMBR and galaxy measurements are fairly accurate, they appear to be in disagreement with each other at approximately ten percent.
While this could just be an observational error, there are some astronomers who suspect that it might be a real difference reflecting something currently missing from our picture of the cosmic expansion process, perhaps connected with the fact that the CMBR arises from a vastly different epoch of cosmic time than does the galaxy data. This third method, gravitational wave events, may help solve the puzzle.
Featured image credit: Shutterstock.
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