Former Engineering undergraduate Dr Keith Bannister recognised for work on Fast Radio Bursts with Pawsey Medal and Malcolm McIntosh Prize for Physical Scientist of the year.
Fast Radio Bursts had not even been discovered when Dr Keith Bannister graduated from UNSW with a degree in Electrical and Electronics Engineering in 2002.
But 20 years later, and following a move into radio astronomy, his exceptional work on FRBs has now been recognised with two prestigious prizes.
Dr Bannister was recently awarded the Malcolm McIntosh Prize for Physical Scientist of the Year 2021, and has also now been honoured with the 2022 Pawsey Medal by the Australian Academy of Science.
Fast Radio Bursts are emitted from objects in space and last for about a millisecond. The cause of them is still the subject of much debate.
Dr Bannister’s work with CSIRO at the Australian Square Kilometre Array Pathfinder (ASKAP) radio telescope in Western Australia has not only helped to find and identify many more of these FRBs, but is also using data from them to answer questions about our universe.
Really big questions. Such as: “How many atoms are there in the universe?”
Which is particularly apt given the fact Dr Bannister believes one of the main things he learned at UNSW was the impact of big ideas.
“I remember having some really great courses at UNSW and it made me realise the power of big and clever ideas and how they can change how things work in the world,” he says.
“I was a Co-op scholar and when I look back on some of things I did during my time at UNSW – namely placements at Pacific Solar and also Alcatel where I wrote a lot of software – really shaped my career.
“There were some really good lecturers who inspired me, especially with regards to algorithms, and I have always enjoyed that ever since. I definitely enjoyed my time at UNSW and it was a great experience.”
Dr Bannister had a taste of space science while studying for his Engineering degree, as he helped an astronomer automate a telescope. He then worked in the aerospace industry in Australia and UK, before completing a PhD in Astronomy and Astrophysics on his return to Sydney.
He joined CSIRO in 2011 and in recent years has helped to devise new and powerful ways to use the ASKAP radio telescope to not only discover the hard-to-find Fast Radio Bursts, but also analyse the information coming from them.
“Fast Radio Bursts are radio waves from outer-space that last for maybe a millisecond – if you click your finger then they are gone,” he says.
“The first one was only discovered in 2007 and they were massively mysterious, both in terms of what they actually were and where they came from.
“I got involved quite early using the ASKAP telescope, which has 36 dish antennae, and what we initially did was point those dishes in different directions to get a fish-eye view of the sky and that meant we were able to detect a lot of FRBs.
“The problem was we couldn’t tell very precisely exactly where they came from. So the next thing we did was to point the antennae in the same direction and look for any FRB that happened in that smaller section of the sky.
“With that method, when an FRB is detected we can triangulate the position of it very accurately and work out exactly what galaxy it has come from.”
The exact cause of FRBs remains unknown and the subject of debate. Dr Bannister says the most likely source are magnetars – neutron stars which are believed to have an extremely powerful magnetic field.
However, undermining that theory is the fact that magnetars are understood to lose their magnetic field after about 10,000 years and some FRBs have been detected coming from very old galaxies which do not contain any young stars.
But while the hunt for the precise source of FRBs continues, Dr Bannister has been collating and analysing the data from those he has found to help try to work out how many atoms there are in the universe.
“Even though we might not know exactly what produces the Fast Radio Burst, we can use them as flashlights to measure a number of things about the universe,” he says.
“And with FRBs, when they travel through space the high-frequency photons go faster than the low-frequency ones and they arrive at the telescope maybe a couple of seconds earlier.
“The difference in the time it takes those different photons to arrive actually tells us the number of atoms the FRB passed through before getting to Earth. The bigger the time difference, the more atoms it went through.
“If we know which galaxy and where in that galaxy the FRB came from, we can calculate how far it travelled. And with information from more and more FRBs we end up plotting a graph showing the amount of atoms each of them passed through versus the distance travelled, which eventually tells us how dense the universe really is.
“And calculating the density of the universe is actually a pretty difficult thing to do.”
In fact, astronomers are still unable to account for roughly 5 per cent of the universe thought to be made of normal matter, known as baryons.
But Dr Bannister and his team’s measurements have confirmed that it does indeed exist in intergalactic space.
For budding engineers and scientists, Dr Bannister advises being ready for the unexpected – after all he could never have planned to be involved with FRBs back when he was a student since they had not even been discovered yet!
“I think what I have done is followed what I am interested in, and that has changed over time. A lot of what I find interesting now didn’t even exist a little while ago,” he says.
“My advice is to be adaptable and keep your eye out for new stuff happening. For example, there is some really interesting things happening now in machine learning and nobody was doing anything like that at all when I was at university.
“The rate of innovation is happening so quickly and it’s likely that 10 years down the track you will end up doing something you didn’t expect, but I think that’s exciting.”