Tuning into the cosmos while keeping the mice at bay
SA scientists aren’t letting anything get in their way in their quest to find out when the first stars and galaxies were formed
Not even mice, a remote island accessible for only three weeks a year and harsh weather conditions can keep a team of SA scientists from trying to piece together exactly when the universe’s first stars were born, using a low-frequency radio telescope they built.
The University of KwaZulu-Natal astronomy team, led by Dr Cynthia Chiang, is using the Prizm telescope they made last year – which sits on the remote Marion Island between SA and the Antarctic and is only accessible by ship – to collect information about the universe during the Cosmic Dawn. This was the period a few hundred million years after the Big Bang.The light from these first stars has always been too dim for optical telescopes and were therefore previously not measured directly.
But now Chiang and her team of astrophysics PhD students, are using the Prizm telescope to collate data that could help in determining when the first stars and galaxies were formed.
To effectively capture data, the site for the telescope had to be free from man-made transmissions such as radio stations and cellphones.Chiang, a senior lecturer at the university’s Astrophysics and Cosmology Research Unit, said the specialised radio telescope observed the sky between 50MHz and 200MHz.
“You may recognise these frequencies as being essentially the same range in which FM radio stations broadcast: in other words, you can think of Prizm as a fancy car radio that’s tuning into all stations at the same time.
“When we tune in to these stations simultaneously, we’re ‘listening’ to the early universe and searching for a very faint and very special signal.
“We believe that when the first stars ignited during the cosmic dawn, they injected energy into the universe.”
The faint signal, Chiang explained, could tell scientists “a great deal about the nature of the first stars and when they appeared”.Earlier this year, astronomers from Arizona State University in the US built Edges, an instrument located in a remote region of Western Australia, where they claim to have already detected a signal from the first stars to have illuminated the universe.
Chiang and her team are eager to see whether their data tell the same story.
They’ve also had to deal with tough weather conditions and the island only being accessible by ship, mainly the SA Agulhas II.
The island lies in the Roaring Forties, an area notorious for high winds, rain and cold temperatures.
“The main challenges for us are the limited access, a three-week access window, only once a year, (and) the mice, who enjoy eating any electronics they can get their tiny paws on”, said Chiang.
But they are hardly fazed.
“The telescope works beautifully, thanks to hard work by the entire team, especially the students, who relentlessly braved the long hikes and harsh weather to get science done.”
So what does this research mean for the man on the street?
“Understanding the nature of the universe is something that humans have wondered about for as long as we've existed.
“It’s rather remarkable that, with specialised telescopes in hand, we can piece together the universe’s ancient history in precise, quantitative ways,” Chiang added.