Cosmic clocks reveal that time was 5 times slower at the dawn of the universe | Science

If you were there, when the universe was born, a second would seem like a second to you, but to us now, 12 billion years later, that initial time would seem to pass very slowly.

Albert Einstein’s theory of general relativity was a turning point in physics in general, and it caused a quantum leap in astronomy and theoretical physics, and it changed the basic concepts of time, space, mass, and energy, making time and space a unified matter. , and creates the concept of time depending on the speed of objects and the intensity of gravity with which they move. Physicality, contraction and expansion of time has become a fundamental concept for understanding the universe.

Although the theory of general relativity underlies astrophysics and cosmology, scientists have not been able to prove the basic premise of the alleged theory of relativity: due to the expansion of the universe, we should see time pass. As the dawn of the universe unfolds, researchers have tried to track it very slowly. However, the way to track these deep-time events has been a difficult dilemma to solve.

Today, scientists have for the first time found a solution to this puzzle, using quasars (quasars) as “clocks” to observe the dilation of time, and they have published their results. Their research This is Natural Astronomy on July 3rd.

Time dilation and quasars

To put it simply, Geraint Lewis, the study’s principal investigator and a professor in the School of Physics and Sydney Astronomical Society at the University of Sydney, explains in a press release published by York Alert (EurekAlert) – “If you were there, when the universe was born, a second would seem like a second to you, but to us now, over 12 billion years, that early time would seem to pass very slowly.”

It can be compared to an ambulance whistle that sounds normal as it passes you and then gets louder as it moves away from you. In this analogy, the ambulance is a distant galaxy and the light emanating from it is a siren. At the source of the light, the emission is normal, but in our view, it expands because the galaxy is far away from our location. .

Professor Lewis and his co-author Dr Brendan Brewer of the University of Auckland used data observed from nearly 200 quasars, the supermassive black holes at the centers of early galaxies, to analyze this time dilation.

Previously, astronomers could confirm this slow motion of the universe over a time horizon equal to roughly half the age of the universe using supernovae (massive exploding stars) as “standard clocks.” Observe them at the enormous distances required to see the universe. But by observing quasars, the time horizon we can see has receded to only about a tenth of the universe, confirming that the universe appears to be accelerating as it ages.

Fireworks display

“While supernovae behave like single flashes of light (making them easier to study), quasars are more complex, like a continuous firework display,” Professor Lewis says. “What we’ve done is unravel this fireworks display and show that quasars can also be used as stable markers of time.” In the Early Universe”.

Professor Lewis worked with astrophysicist Dr Brewer to study the details of 190 quasars observed over two decades and was able to combine observations made in different colors (or different wavelengths: green light, red light, infrared) to rank the ‘beats’. Each of the quasars, and by using Bayesian inference (a type of statistical inference that uses the Bayes factor to generate an estimate of the probability of a hypothesis given the discovery of new evidence), they found that the expansion of the universe was imprinted. On the “beats” of each quasar.

Professor Lewis says, “With this amazing data, we were able to chart the pulses of quasar clocks and reveal the effect of the expansion of space.” These results confirm Einstein’s theory of the expansion of the universe, but contradict earlier studies that failed. To determine the time dilation of distant quasars.

Professor Lewis continues, “Those previous studies made people question whether quasars were really cosmic bodies or whether the broader concept of space was correct. But with this new data and analysis, we were able to observe. Quasars were difficult to observe, and we found that they behave exactly as Einstein’s relativity predicted.”