Time seems to flow five times slower in the early universe, according to a scientific study, which for the first time uses extraordinarily bright cosmic objects, quasars, to confirm this strange phenomenon.
The theory of relativity posed by Albert Einstein predicts that because of the expansion of the Universe, “we should observe the distant Universe growing in slow motion”, explains to AFP Geraint Lewis, astrophysicist at the University of Sydney and first author of the study published Monday in Nature Astronomy.
Researchers had observed stars ending their lives in explosions, supernovae, to show that time seemed to pass twice as slowly when the Universe was half its current age, which is 13.8 billion years. The new study uses quasars, which are among the brightest objects in existence, to date back up to a billion years after the birth of the Universe. Time seems to flow five times slower there, according to the study.
“Everything seems to be running in slow motion” to the current observer, according to Geraint Lewis, but “if I could magically transport you ten billion years ago to drop you off near one of these quasars, and watch your stopwatch , everything would seem normal to you, ”he explained. “A second would be a second. »
To measure the phenomenon, called cosmological time dilation, Lewis and New Zealand University of Auckland statistician Brendon Brewer analyzed data from 190 quasars, collected over 20 years.
Quasars, galactic nuclei housing a supermassive black hole at their center, are reputed to be the most energetic objects in the cosmos, which makes them “very practical beacons for mapping the Universe”, according to the astrophysicist. The difficulty was to make them into cosmic clocks as easy to use as supernovas. The latter provide a single but reliable signal over time.
For quasars, the researchers achieved their goal thanks to a large number of data and recent progress in the statistical understanding of random events.
In this case, the researchers have succeeded in interpreting the multiple shocks that occur when the quasar’s black hole absorbs matter.
Geraint Lewis likened it to a firework display, in which the large sprays appear to explode randomly, but the elements “brighten and then fade” in a defined and regular time frame.
“We’ve stripped down this fireworks show, and shown that quasars too can be used as time beacons of the early universe,” he said. And thus demonstrated that “Einstein is right once again”.
Previous attempts to use quasars to measure cosmological time dilation theory had failed, resulting in “strange suggestions”. Like that quasars were not as distant objects as observed.
The new study “puts things in their place”, showing that these objects also obey the laws of the Universe.