Early universe time quasar illustration.jpeg

In the early universe time seems to have run 5 times slower

Scientists have observed for the first time the early universe functioning in "extremely slow motion."


For the first time, scientists have discerned the early universe unfolding dramatically slower, shedding light on one of Einstein’s enigmatic concepts of an expanding universe.

Early Universe Time, 5 Times Slower

Einstein’s general theory of relativity posits that our observations of the distant—and therefore ancient—universe should reveal a much slower tempo than the present. Nonetheless, examining such a remote period has long stumped researchers. In a groundbreaking study, scientists have now solved this puzzle by using quasars as cosmic timekeepers.


“The universe, when just over a billion years old, seemed to flow five times slower,” said Professor Geraint Lewis, the study’s lead author from the University of Sydney’s School of Physics and Sydney Institute for Astronomy. “From our standpoint, over 12 billion years into the future, the pace of that early epoch appears sluggish.”

The study has been published in Nature Astronomy.

Quasars as Cosmic Clocks

Professor Lewis and his collaborator Dr. Brendon Brewer from the University of Auckland relied on data from nearly 200 quasars—overactive supermassive black holes situated at the cores of ancient galaxies—to scrutinize this time dilation phenomenon.

“Einstein made us understand that time and space are interlaced. From the Big Bang’s singularity, the universe has been in a state of expansion,” Professor Lewis explained. “This spatial expansion suggests that our observations of the early universe should appear significantly slower than how time flows currently. This paper confirms this back to roughly a billion years post the Big Bang.”


In the past, astronomers used supernovae, gigantic exploding stars, as ‘standard clocks’ to verify this slower universe. Still, despite their extraordinary luminosity, supernovae are challenging to observe at the vast distances required to inspect the early universe.

Unraveling the Quasar Fireworks

By observing quasars, this time boundary has been traced back to merely a tenth of the universe’s age, affirming that the universe seems to accelerate with age.

“Unlike supernovae that act like a single flash of light, quasars are more intricate, akin to a continuing firework display,” Professor Lewis pointed out. “We’ve managed to decode this firework spectacle, demonstrating that quasars too can serve as standard time markers for the early universe.”

Professor Lewis collaborated with Astro-statistician Dr. Brewer to examine the specifics of 190 quasars observed over two decades. By standardizing the ‘ticking’ of each quasar through observations taken at various colors (or wavelengths), they pinpointed the universe’s expansion in each quasar’s ticking using Bayesian analysis.

“We managed to map the tick of the quasar clocks, exposing the impact of expanding space,” Professor Lewis shared.


These findings bolster Einstein’s depiction of an expanding universe but contradict previous studies that couldn’t pinpoint the time dilation of distant quasars.

“Prior studies led to doubts whether quasars are truly cosmological objects, or if the notion of expanding space is accurate,” Professor Lewis said. “However, with our new data and analysis, we’ve uncovered the elusive tick of the quasars, and they behave precisely as Einstein’s relativity foretells.”

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Written by Ivan Petricevic

I've been writing passionately about ancient civilizations, history, alien life, and various other subjects for more than eight years. You may have seen me appear on Discovery Channel's What On Earth series, History Channel's Ancient Aliens, and Gaia's Ancient Civilizations among others.

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