Our studies suggest that time moved more slowly in the early Universe due to the distinctive influence velocity has on the appearance of the passage of time.
At least, that’s how it seems nearly 13 billion years after the light left it. By analyzing the fluctuations of bright galaxies called quasar galaxies in the early Universe, astronomer Geraint Lewis of the University of Sydney in Australia and statistician Brendon Brewer of the University of Auckland have observed time dilation for the first time in the Cosmic Dawn.
They discovered that these fluctuations unfold five times slower than they would if they were taking place locally due to the rapid expansion of the Universe.
This is the farthest we’ve ever observed time dilation in operation, and it helps with a number of issues. It demonstrates that quasars are in conformity with the standard model of cosmology and that we can account for time dilation in our studies of their behavior even over enormous gaps in space-time.
As Lewis puts it, “time appears to flow five times slower” when looking back to when the Universe was just over a billion years old.
According to the author, “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.”
Space and time in the Universe are closely linked; nevertheless, this connection is not readily apparent in our everyday lives. This is how we know the expansion of the universe is speeding up. Light from extremely distant sources has a longer, redder wavelength because of the expansion of space between them.
The Doppler effect is real and may be felt right here on Earth. Imagine how the sound of an ambulance siren fades away as the vehicle speeds away from you.
The ambulance here represents a faraway galaxy, and the light represents the ambulance’s siren. The emission is normal at the source but seems distorted when viewed from our location.
About halfway across the observable Universe, we see supernova explosions, proving that the same thing should happen in time.
The passage of time is usual for us. Someone observing the supernova explosion from close by might have the impression that time is passing regularly, too. However, since the two locations are moving at different speeds, we see the supernova unfold in slow motion.
Although quasars in the early Universe have been anticipated to exhibit a comparable effect, they are not the same thing as supernovae. Quasar galaxies are ones in which the central supermassive black hole is actively consuming matter from its surrounding galaxy. As the matter in the region of the black hole is heated and begins to flutter and flicker due to the feeding process, a significant volume of light is produced.
“Where supernovae act like a single flash of light, making them easier to study, quasars are more complex, like an ongoing firework display,” explains Lewis. We have decoded this fireworks display, proving that quasars, like other conventional markers of time in the early Universe, may be used to date events in the cosmos.
Over the course of two decades, Lewis and Brewer analyzed data from a sample of 190 quasars, spanning an epoch of 2.45 to 12.17 billion years (the Big Bang occurred 13.8 billion years ago). With over 200 observations per quasar, they were able to reconstruct the quasars’ variations in great detail.
Scientists once believed that quasar variability did not reveal the effects of time dilation, however, this was due to the samples being small and the observations taking place over a much shorter time period.
The two scientists found that quasars appear to flicker in slow motion compared to more modern quasars after drastically increasing the number of quasars observed and the length of the observations.
Lewis states that previous research had cast doubt on whether or not quasars are genuine cosmic objects and on the whole concept of space expanding. “However, with these new data and analysis, we have been able to locate the enigmatic tick of the quasars, and their behavior is consistent with that predicted by Einstein’s general theory of relativity.”
