Have you ever wondered what was the very first star to light up the Universe? That moment in time, when all things began? Well, Professor Lisa Kewley, Director of the Australian Research Centre for Excellence in All Sky Astrophysics in 3 Dimensions (ASTRO 3D) is leading the hunt. And if you think finding your keys in the morning is difficult, imagine searching for a handful of select stars amidst our universe, which is made up of an estimated two trillion galaxies, each one home to 100 billion stars.
Kewley has her sights set on another daunting challenge. She also wants to ensure that 50% of all people working in ASTRO 3D are women. As a student, she wasn’t sure there was a place for her in a field largely dominated by men. “I honestly thought I was going to hit a glass ceiling,” she told The Brilliant. “I had a back-up plan all lined up that when I hit that glass ceiling, I was going to leave and I was going to do this other thing. It’s just not surprising that women leave, because when they look up, they don’t see the women there at those senior levels.”
While employed as a postdoctoral fellow at the Harvard–Smithsonian Center for Astrophysics in the US, Kewley realised it didn’t have to be that way. “My eyes were opened when I went to the USA, because there were a lot more women in astronomy. I could see that there were senior women in the field and they were having a family and even bringing children to conferences. I did not have that picture when I was doing my PhD in Australia, because I didn’t see it. My time there actually changed my mind about what I would be able to achieve.”
From starry-eyed beginnings to epic discoveries
It’s a good thing that astronomy and Kewley stayed together, because they’re made for each other.
It was in Year 11 at high school that Kewley “fell in love” with astronomy.
She spent her pocket money on a book containing photographs of galaxies from the Hubble Space Telescope. “I just thought they were the most beautiful things,” she recalls. Her physics teacher, who shared her passion for astronomy, brought in his own telescope for the class to do astronomy experiments instead of physics experiments. Attending a national science summer school (now known as the National Youth Science Forum) at the Mount Stromlo Observatory and listening to astronomers give talks was a turning point. “I could not believe that people were being paid to do astronomy,” she says.
Kewley’s father, a physicist at the Defence Science and Technology group in Adelaide, introduced her to colleagues who were former astronomers. They helped her map out what and when to study. Ever enthusiastic, Kewley continued to talk to astronomers throughout her studies to find opportunities to build up her experience.
During an undergraduate summer scholar program at ANU, while working with Professor Peter McGregor, Kewley got her first taste of seeing the Universe through data captured from telescopes.
“Peter had all of this data on Jupiter and my job was to ‘reduce‘ the data.” She explains the process: “When you first get data it is totally black, you can’t see anything, you have to remove all of the ‘noise’ – the reflection, the sky – and then suddenly you can see something remarkable. In this case, it was the moment a comet hit Jupiter.”
Since that first astonishing sight, Kewley has gone on to make a number of fundamental advances – including understanding how galaxies are powered, and the star-formation history of the Universe.
When a star dies, it releases oxygen. By analysing that oxygen history, Kewley has been able to determine how many generations of stars have formed and died within a galaxy, which in turn determines the age of that galaxy. This has proven critical in understanding how galaxies like the Milky Way are formed, from the Big Bang to the present day.
And now Kewley and her team at ASTRO 3D are hot on the heels of those first stars.
Our vision is to understand how the first stars, and then the first galaxies, formed and evolved across the last 13 billion years of cosmic time. We do that by combining radio and optical telescopes equally in a way that hasn’t been done before, and then build a big theory program, which hadn’t been possible in Australia because we didn’t have the theorists. But over the previous 10 years Australia has been hiring theorists, and so we now have a critical mass of theorists as well as optical and radio astronomers.”
ASTRO 3D’s galactic archaeology program, founded in 2017, holds the world record for discovering so-called ‘pristine stars’, which were formed very soon after the Big Bang. “The most exciting one was discovered very recently by Thomas Nordlander,” says Kewley, referring to an ANU astronomer. “It’s got a very low amount of iron, which suggests that it was basically enriched by only one supernova before it was formed. This is tremendously exciting for our understanding of the earliest times of the Universe.
And even more tantalising is the location of these pristine stars.
“These were actually discovered in our own Milky Way. So the Milky Way is very, very old, and we think some of the stars in our Milky Way were the first stars in the Universe.”
Kewley and her team have also been working on the so-called ‘Epoch of Reionisation‘, or the moment when the first stars emerged. “Using the Murchison Widefield Array in Western Australia, our team has made the most sensitive measurements to date to detect when and where that exactly happened,” says Kewley. She says that while the team hasn’t detected it yet, “we are narrowing it down.”
Fixing the gender gap in astronomy and beyond
Kewley’s ambitions for ASTRO 3D also have implications for women in astronomy globally. “By the end of 2021, our goal is to achieve 50% female representation at all levels.” To put this into perspective, in Australia women represent only 16% of the STEM workforce in and 28% of management positions, according to the Women in STEM Decadal Plan
“There are three reasons for 50% representation. The first reason is obvious: women represent 50% of the population. The second reason is that you need women on selection, promotion, awards and policy committees and you need women doing education and outreach so that younger women have the role models. But without 50% of women, you are overburdening the women in your organisation as there is a lot of work on these committees and outreach. And the third reason is that women leave the physical sciences two to three times more than men.”
Kewley says longitudinal studies show women leave for reasons such as the lack of a good relationship with their supervisor, the lack of visible women with a good balance between work and family, and the fear that they can’t achieve a senior position.
With women now making up 40% of PhD students at ASTRO 3D, and 50% of ASTRO 3D-employed postdoctoral researchers, things are beginning to move in a positive direction, Kewley says.
The student pool remains an issue. “We don’t decide who the students are in astronomy. It’s actually decided by university-wide colleges, based on the number of Commonwealth places for PhD students, so it’s difficult for us to control the gender balance for our female students.”
The other area of complexity is with ASTRO 3D’s international partner organisations. Kewley says she is about to require partner organisations to establish their own 50% program for their ASTRO 3D members.
Kewley is also taking her formidable modelling skills and applying them across the STEM sector to examine what is driving the lack of equity more broadly. Based on publicly available information from the Higher Education Research Data Collection and the Australian Academy of Science SAGE Database, she has found that, over the last 30 years, two to three times as many women as men have left the sector. There may also have been implicit bias in selection and promotion processes in STEM over this period.
I ran the models forward in time and I show that you can actually fix the gender gap so you can achieve 50:50 across the STEM in Australia within 20 years with two initiatives; you need to have 50:50 in hiring but you also need to have 50:50 retention.”
In order to achieve retention rates, Kewley argues, nationwide exit surveys should be mandatory and should be run by the government. She also argues that that leadership opportunities should be opt-out, rather than opt-in, in order to change the promotion bias towards men, and to encourage women to reach promotion earlier.
What is needed, Kewley says, is nothing short of “a massive culture change.” Massive, yet, she believes, achievable. “We are a relatively small country, and awareness of these issues is increasing. Change across the STEM sector is possible in a reasonable timeframe in Australia. In larger countries, with many private universities and organisations, it is much harder. Achieving 50:50 in Australia is possible within a reasonable timeframe.”
Public and private organisations and individuals all have a part to play in making this happen, says Kewley. “I think government-funded organisations have a civic duty to hire people to ensure that the diversity of their organisation reflects the diversity within the broader community. Leaders, CEOs, and change-makers need to come together to drive this change for the benefit of Australia.”
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Article by Kylie Ahern
Photo Credit: Cristy Roberts
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