Scientists observed for the first time that in the early Universe, time passed "five times slower". They analyzed data from quasar objects powered by "supermassive" black holes at the centers of the first galaxies, and used them to measure time shortly after the beginning of the Universe. "Looking back to a time when the Universe was just over a billion years old, we see that time seems to flow five times slower [just after the Big Bang]," says Lewis, lead author of the study published in the journal scientific Nature Astronomy. "If you were there, in this early universe, a second would seem like a second — but from our position, over 12 billion years in the future, that initial time seems to drag." "Thanks to Einstein, we know that time and space are intertwined, and since the beginning of time in the Big Bang singularity, the Universe has been expanding," he says. "This expansion of space means that our observations of the early Universe should appear much slower than how time flows today."

"In this paper, we established that this goes back to about a billion years after the Big Bang."