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Gravitational waves will inhabit a cosmic riddle



When neutron stars collide, they emit light and gravitational waves, as shown in the illustrations of this artist. By comparing the timing of two emissions from many different neutron-star pools, researchers can measure how fast the universe develops. Authorship: R.Hurt / Caltech-JPL

Measuring gravitational waves from about 50 binary neutron stars over the next decade will finally resolve the intense debate about how fast our universe is expanding, according to the findings of an international team that includes the University College London (UCL) and the cosmologists of the Flatiron Institute.
Space is expanding over 1

3.8 billion years. Its current rate of expansion, known as the "Hubble constant", gives the time since the Big Bang.

However, the two best methods used to measure Hubble's constant are contradictory, indicating that our understanding of the structure and history of the universe – the "standard cosmological model" – may be wrong.

A study published today in Physical Review Letters shows how new independent data from gravitational waves emitted by binary neutron stars are called "standard lilacs" of a fracture, a dead end between conflicting measurements once and for all .

"We calculated that by observing 50 binary neutron stars over the next decade, we will have enough data from the gravitational waves to independently determine the best measurement." Hubble's Constant, "said the lead author – Dr. Stephen Fini of the Center for Computing Astrophysics at the Institute Flighton in New York. "We should be able to detect a sufficient number of mergers to answer this question for about ten or ten years."

Hubble's Constant, product of Edwin Hubble and Georges Leamatot in the 1920s years, is one of the most important numbers in cosmology.Permanent "is necessary to evaluate the curvature of space and age of the universe, as well as to study its fate," said the co-author of the UCL study, professor of physics and astronomy Hirana Peiris

using two methods, one observation of cepheid stars and supernovae in the local universe, as well as the second with the use of measurements of cosmic background radiation from the early universe, but these methods do not give the same values, which means that our standard cosmological model may be imperfect [1 9659004] Feeney, Peiris and colleagues have developed a universally applicable technique that calculates how gravitational wave data will solve a problem.

Gravitational waves are emitted when binary neutron stars spiral to each other before collision in a bright light flash can be detected by telescopes. UCL researchers were involved in detecting the first light from the gravitational wave event in August 2017.

Binary events of neutron stars are rare, but they are of inestimable value to provide another way of tracking the expansion of the universe. The gravitational waves they emit cause space-time pulsations that can be detected by the Gravitational-Wave Laser Interferometer Observatory (LIGO) and the Virgo experiments, giving an accurate measurement of the distance from the Earth.

Additional detection of light from a coincident explosion may determine a system's speed and, therefore, calculate a constant Hubble using the Hubble law.

For this research, researchers have modeled how many such observations will be needed to address the issue of measuring Hubble's constant.

"This, in turn, will lead to the most accurate picture of how the universe expands and helps to improve the standard cosmological model," Professor Peris summed up.


Explore further:
Can gravitational waves detect how fast our universe is expanding?

Additional information:
Steven M. Fini, Hiranya V. Peiris, Andrew R. Williamson, Samaya M. Nissanke, Daniel J. Mortlock, Justin Alsing and Dan Skolnich, "Prospects for Hubble Constant Humor Distribution with Standard Sirens" will be published in Physical Review Letters on Thursday, February 14, 2019.

Reference of the journal:
Physical Letters Review

Granted:
The Simons Foundation


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