Time is moving faster now than it did in the early stages of the universe, according to a study carried out by researchers in Australia and New Zealand.
At around a billion years after the Big Bang, time passed up to five times slower, as predicted in Einstein’s general theory of relativity.
“Looking back to a time when the universe was just over a billion years old, we see time appearing to flow five times slower,” says the University of Sydney’s Geraint Lewis, who was a lead author of the study.
“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.”
This observation was made possible through the study of distant, ultra-bright quasars, which are supermassive black holes surrounded by a cloud of matter.
These quasars emit radio waves, which can be perceived by a radio telescope.
How old is the universe?
Scientists from the Universities of Sydney and Auckland looked at the emissions of “190 quasars observed over two decades” to witness the explosive output of the quasars, which from these distances looks like a rhythmic “ticking”.
This ticking is then analysed using a technique that generates statical regularity out of what might otherwise appear to be a series of random explosions, allowing them to be approached like the ticking of a clock.
“Where supernovae act like a single flash of light, making them easier to study, quasars are more complex, like an ongoing firework display,” says Lewis. “What we have done is unravel this firework display, showing that quasars, too, can be used as standard markers of time for the early universe.”
This analysis let Lewis and his partner Dr Brendon Brewer look back to a time a billion years after the Big Bang, more than 12 billion years ago.
“With these exquisite data, we were able to chart the tick of the quasar clocks, revealing the influence of expanding space,” says Lewis.
This work has been written up in a study for Nature Astronomy, in which Brewer and Lewis argue that this quasar data discredits the notion that the behaviour of these distant quasars represents “a substantial challenge to the standard cosmological model”.
Meanwhile, last week scientists at the University of Minnesota witnessed a supernova explosion that took place 11 billion years ago, the collapse of a star more than 500 times larger than our Sun.
