Time appears to flow five times slower in the early universe, according to a scientific study, which for the first time uses unusually bright cosmic bodies, quasars, to confirm this strange phenomenon.
Albert Einstein’s theory of relativity predicts that due to the expansion of the universe, “we should observe the growth of the distant universe in slow motion,” explains to France Press Geraint Lewis, an astrophysicist at the University of Sydney and first author of the study published Monday in natural astronomy.
The researchers observed that stars end 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, dating 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 going in slow motion” to the present observer, according to Geraint Lewis, but “if I could magically teleport you ten billion years ago to drop you near one of these quasars, and watch your stopwatch, everything would seem normal to you.” he explained. “The second will be a second.”
To measure this phenomenon, called cosmic time dilation, Lewis and New Zealand University of Auckland statistician Brendon Brewer analyzed data from 190 quasars, collected over a 20-year period.
Quasars, galactic nuclei with a supermassive black hole at their centre, are reputed to be the most energetic objects in the universe, making them “very practical beacons for mapping the universe,” according to the astrophysicist. The difficulty was turning them into supernova-friendly cosmic clocks. The latter provides a single but reliable signal over time.
For quasars, the researchers achieved their goal thanks to a large amount of data and recent advances in the statistical understanding of random events.
In this case, the researchers succeeded in explaining the multiple shocks that occur when matter is sucked in by a quasar’s black hole.
Geraint Lewis likened it to a pyrotechnic show, in which large sprays seem to go off at random, but the elements “light up and then fade” in a set, regular time frame.
“We stripped away this fireworks display, and showed that quasars, too, can be used as time beacons for the early universe,” he said. In doing so, he proved that “Einstein is right again.”
Previous attempts to use quasars to measure cosmic time dilation theory have failed, leading to “strange suggestions”. Like that, quasars were not such distant objects as was observed.
The new study “puts things in their place,” showing that these things are also subject to the laws of the universe.
