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hubie [soylentnews.org] writes:

Result confirms time-dilation expectations of Einstein's general relativity [sydney.edu.au]:

Scientists have for the first time observed the early universe running in extreme slow motion, unlocking one of the mysteries of Einstein's expanding universe.

Einstein's general theory of relativity means that we should observe the distant – and hence ancient – universe running much slower than the present day. However, peering back that far in time has proven elusive. Scientists have now cracked that mystery by using quasars as 'clocks'.

"Looking back to a time when the universe was just over a billion years old, we see time appearing to flow five times slower," said lead author of the study, Professor Geraint Lewis from the School of Physics and Sydney Institute for Astronomy at the University of Sydney.

"If you were there, in this infant universe, one second would seem like one second – but from our position, more than 12 billion years into the future, that early time appears to drag."

[...] "Thanks to Einstein, we know that time and space are intertwined and, since the dawn of time in the singularity of the Big Bang, the universe has been expanding," Professor Lewis said.

"This expansion of space means that our observations of the early universe should appear to be much slower than time flows today.

[...] Professor Lewis worked with astro-statistician Dr Brewer to examine details of 190 quasars observed over two decades. Combining the observations taken at different colours (or wavelengths) – green light, red light and into the infrared – they were able to standardise the 'ticking' of each quasar. Through the application of Bayesian analysis, they found the expansion of the universe imprinted on each quasar's ticking.

"With these exquisite data, we were able to chart the tick of the quasar clocks, revealing the influence of expanding space," Professor Lewis said.

You can look at their source data [zenodo.org] if you want to do your own number crunching.

Journal Reference:
Lewis, G.F., Brewer, B.J. Detection of the cosmological time dilation of high-redshift quasars. Nat Astron (2023). https://doi.org/10.1038/s41550-023-02029-2 [doi.org]

Original Submission