When you’re in charge of the largest low-frequency telescope ever built and the reams of data it will generate, you get to watch the origins of the universe. For astrophysicist Dr Sarah Pearce, the “next big thing” is the last Big Bang.
Here’s an interesting fact: the big discoveries that some telescopes are famous for are not necessarily what they were built for. Most telescopes will do the things that their designers expected, and you always want an instrument to help you see as much as possible. But then, who knows what you’ll find?
One of the big things at the moment in my field are fast radio bursts. These are very, very bright but extremely short pulses of energy, which were only discovered in the last 15 years. CSIRO’s new ASKAP telescope (currently operating in WA) is really great at finding these fast radio bursts. In fact, it’s found 42 so far, but when it was first designed we didn’t even know they existed. So that’s the key to building a really good telescope: it can reveal phenomena that you didn’t even imagine at the time it was built.
I’ve recently been appointed Telescope Director of the SKA Observatory’s new low-frequency radio telescope in WA. When it’s built, in 2028, this will be the world’s largest low-frequency radio telescope, by quite a margin. And this is the first time that Australia will have hosted one of these mega science projects on behalf of the international community – something like the Large Hadron Collider.
It’s being built with a few key science projects in mind, but the main one is what we call the Epoch of Reionisation – which is close in time to the “cosmic dawn”. Essentially, it’s the time when the very first stars and galaxies started to shine after the Big Bang. No telescope has ever been able to detect this yet. But the SKA telescope in Australia aims to be the first to detect it, and hopefully map what the universe looked like at that time.
In the past if you wanted a telescope, one country could build it. But what you need to build now, in order to arrive at that cutting edge, is larger than any one country can deliver.
This isn’t an optical telescope. It works in the same way a TV antenna or car radio antenna detects radio electromagnetic waves. The SKA will have antennas spread across 60 kilometres of the desert in Western Australia that will be able to detect the radio waves that come from distant stars and galaxies in the universe. But those radio waves are extremely faint, so we will use a lot of antennas – there will be around 130,000 of them. Each one looks a bit like a Christmas tree made of aluminium, standing about two metres tall. They’re designed very specifically to allow us to cover a particular range of the spectrum, which is 50 to 350 megahertz.
A project like this is going to need some serious computing power to be able to understand the data. SKA will have to deal with seven terrabytes of data a second, which is like analysing 100,000 home broadband connections constantly. That’s an enormous data challenge: this will be the scientific instrument with the highest data flow in the world. And so we hope that this will teach us not only how to deal with astronomy data, but ways it can be applied to other large-scale data projects, whether they’re in science or industry.
So we will be absolutely pushing the boundaries. I think we will learn a lot about processing large amounts of data, which you can’t do by hand anymore in astronomy. Sometimes we don’t even know what we’re looking for. And so it’s using things like artificial intelligence and machine learning to help us find the things that we weren’t even expecting.
For almost as long as I can remember I’ve been interested in the big questions. What’s the universe made of? What’s an atom? I read a lot of books as a young person as I tried to find the answers. Pretty soon I was wondering, how does quantum mechanics work?
For almost as long as I can remember I’ve been interested in the big questions. What’s the universe made of? What’s an atom? I read a lot of books as a young person as I tried to find the answers. Pretty soon I was wondering, how does quantum mechanics work?
By the time I was 14, I knew that I wanted to be an astrophysicist. I remember going out into the back garden at night with my binoculars and my star chart and trying to work out what stars I was looking at – there were no smart phone apps back then to help.
When I was 17 I went to Space School in the UK – it’s a week-long summer school focusing on space. That was a real milestone for me. It was the first time I had ever really been with my people, who were also fascinated by space. That experience was fundamental in making me realise that this was the direction I wanted my career to go.
We recently celebrated the 50th anniversary of Apollo 11’s landing on the Moon out at the Parkes radio telescope in NSW, which was fantastic. I was lucky to lead the countdown to the exact time, 50 years before, when the Eagle landed. It was wonderful seeing all the kids there who were so excited and inspired. And I remember seeing them and being reminded of myself at their age, and thinking, “This is exactly what I’ve always wanted to do – running astronomy facilities that are absolutely world class, and helping people doing great science.”
I certainly have an astronomy facility to run now.
Originally published by Cosmos as SKA’s low-frequency radio telescope promises a first look at the origin of the Universe
Sarah Pearce
Dr Sarah Pearce, currently Acting Chief Scientist of Australia’s national science agency CSIRO, was recently appointed director of the biggest low-frequency telescope in the world, soon to be under construction now in the desert of Western Australia.
