By AVNEET HUNDEL and CHARLOTTE MORTON
A Melbourne scientist is trying to pinpoint the exact moment in time when the universe went from dark to light, centuries after the Big Bang.
University of Melbourne Cosmologist Dr Nichole Barry, along with her team, has taken on the extraordinary task of identifying the moment light first filled the universe. The phenomenon is known as the Epoch of Reionization and occurred about 300,000 years after the Big Bang.
Dr Barry's research is crucial to settle arguments among the scientific community on what exactly took place between the Big Bang and the beginning of light.
"There’s a whole lot of questions on what actually was occurring in that period. We can try to fill in that gap in our knowledge by looking at the Epoch of Reionization," she said.
In order to identify the moment using a radio telescope, Dr Barry has to travel 10 hours from Perth to the Western Australian outback. The area is so remote, radio waves do not interfere with the sensitive equipment.
Dr Barry said there were no galaxies or stars when the universe was dark.
“You have a long time period of about a billion years where gravity is coalescing stuff together in order to make these first galaxies and stars,” Dr Barry said.
“It’s really hard to see those first stars in galaxies. We barely get any of their light by the time it reaches earth, and that light can get absorbed by stuff in the way,” she said.
Dr Barry said the radio telescopes, called interferometers, were spread out across the Western Australian outback.
“The real complexity that comes with a radio interferometer is the fact that you have so many of these, so you need giant computers and computer clusters, in order to analyse any of this data.
"So while on the surface it looks like a really simple instrument, it’s actually quite complex in its brain."
Dr Barry said radio interferometers were used to find faint bits of "glow" in the universe, which is extremely difficult.
“The analogy is that trying to measure the Epoch of Reionization is like trying to see a light bulb on Pluto in a lit stadium,” Dr Barry said.
“So the lit stadium being all the stuff in between you and the Epoch of Reionization and all the galaxies that ever were, essentially are emitting light, and they’re really bright and sometimes they can be in the way.”
As a result, Dr Barry’s research takes a very long time, with her latest project taking about 900 hours throughout 2018 and 2019.
“If you observe for longer you can see fainter things,” she said.
Dr Barry is part of a collaboration with other universities from around the world conducting research on the Epoch of Reionization. This collaboration has formed the Murchison Widefield Array (MWA).
As part of MWA, researchers have built a huge radio interferometer in the Western Australian outback.
Since 2013 data has been collected using this technology around the world and Dr Barry, along with her fellow researchers, have been using it to determine the Epoch of Reionization.
“It’s driving our technological limits with computers and some of the things we have planned for the future aren’t currently feasible with modern day computers, servers and networks,” Dr Barry said.
In the future, Dr Barry plans on using the Square Kilometre Array (SKA), which will be the largest radio telescope in the world, to collect mass data about the Epoch of Reionization.
The SKA is will made up of thousands of interferometers grouped together.
Dr Barry said the SKA location has not been finalised, but could also be established in the Western Australian outback.
"It's going to be spread out as far as the eye can see. With the MWA it only goes about 3km, the SKA will go out to 65km," she said.
The data that will be collected using the SKA “basically amounts to downloading the entire internet every year”.
“The necessary infrastructure you would need to actually process that, store that, move that is not currently available so people are currently researching ways to try and make that even feasible,” she said.
“We plan on developing the technology in order to make that happen, which would benefit everybody.”
Dr Barry also plans on making a movie of the universe forming using images collected from the SKA.