In this episode of Astrophysics for All, I’m joined by Professor Céline Bœhm, an astroparticle physicist and Professor of Particle Physics at the University of Sydney, whose research focuses on dark matter and the fundamental structure of the universe.

Although we can’t see dark matter directly, it makes up most of the matter in the universe. So how do we know it exists — and why has it been so difficult to detect?

In this conversation, we explore how scientists use galaxies, the cosmic microwave background, and particle physics to piece together clues about dark matter’s nature. We also discuss how theorists and experimentalists work together, what makes dark matter such a challenging problem, and what discovering it could mean for our understanding of the universe.

Professor Bœhm also shares her journey into astrophysics and her advice for students interested in exploring physics at the intersection of the very small and the very large.

Dr Ben Montet is a Scientia Associate Professor at UNSW Sydney. He completed his PhD in astrophysics at Caltech and was a Carl Sagan Fellow at the University of Chicago. Dr Montet is a leading exoplanet researcher who uses data from missions like NASA’s Kepler and TESS to discover and study planets beyond our Solar System, uncovering the diversity of planetary systems across our galaxy.

In our conversation, we explore how astronomers detect planets using tiny dips in starlight, and how missions like Kepler and TESS have revolutionised exoplanet discovery. We also discuss his research on a “hot Jupiter” that revealed a hidden companion planet, challenging current models of planetary systems.

We then look at how stars influence whether life is possible, from flares to magnetic activity, and how machine learning is helping uncover new discoveries in massive datasets. Finally, Dr Montet shares his journey into astronomy and advice for students, emphasising curiosity, coding, and taking initiative early.

In this episode of Astrophysics for All, I speak with Dr Caroline Foster, an observational astronomer at UNSW Sydney who studies how galaxies form, grow, and evolve over billions of years.

We explore how astronomers use light to measure the motions and chemistry of stars, how galaxies grow through mergers and star formation, and why some galaxies gradually stop rotating as they age. Dr Foster also explains how globular clusters—ancient, tightly packed groups of stars—act like cosmic fossils that help astronomers uncover the hidden histories of galaxies.

Dr Foster shares how she first became interested in physics and offers advice for students who want to pursue astronomy, highlighting curiosity, mathematics, and the excitement of exploring the biggest questions about the universe.

What if everything we can see in the universe—stars, planets, galaxies, and even ourselves—makes up less than 5% of reality?

In this episode of Astrophysics for All, I sit down with Professor Geraint Lewis, a cosmologist at the Sydney Institute for Astronomy, to explore the invisible universe. Originally from Wales, Professor Lewis completed his undergraduate degree at the University of London and went on to earn his PhD in astrophysics from the University of Cambridge’s Institute of Astronomy. He has worked at research institutions in the United States and Canada before joining the University of Sydney, where he now leads the Gravitational Astrophysics Group.

Although everything we can see—from stars to galaxies to ourselves—makes up less than 5% of the cosmos, the rest is dominated by mysterious dark matter and dark energy that scientists are still struggling to understand.

Professor Lewis explains how astronomers use gravitational lensing to map invisible matter, how galaxies grow by tearing apart smaller ones in a process known as galactic cannibalism, and why studying these phenomena can reveal the hidden structure of the universe. Along the way, Professor Lewis shares what life as a cosmologist looks like and offers practical advice for students curious about pursuing physics and astrophysics.

In this episode of Astrophysics for All, I'm joined by Professor Sarah Brough, Head of the School of Physics at University of New South Wales and an observational astronomer studying how galaxies grow and evolve over billions of years.

Professor Brough explores some of the faintest and most elusive structures in the Universe: tidal features and intracluster light. She explains how these delicate traces reveal galaxies’ hidden histories of mergers, disruption, and transformation. Professor Sarah Brough discusses her research on galaxy evolution, focusing on tidal features and intracluster light. She explains the challenges of detecting these faint cosmic phenomena and the technological advancements that have made such studies possible.

How is Antarctica's unique environment revolutionising the way astronomers observe the universe? In this episode, Professor Michael Ashley shares the advantages, challenges, and groundbreaking discoveries made from the icy continent.

Professor Ashley is an astrophysicist at the University of New South Wales, specialising in astronomical instrumentation and observational astronomy. He completed his Master’s at Caltech and his PhD at the Australian National University (ANU). His work focuses on conducting cutting-edge observations from Antarctica, one of the world’s most extreme and scientifically valuable observing sites. He has pioneered the use of robotic telescopes in remote environments, enabling studies of transient celestial events such as supernovae and gravitational wave sources.

Clouds might look soft and harmless, but they play one of the biggest roles in deciding Earth’s future climate.

In this episode of Astrophysics for All, I'm speaking with Professor Steven Sherwood, a leading climate scientist at UNSW Sydney, about how physics, computer models, and satellite data help us understand the atmosphere.

Professor Sherwood holds a physics degree from MIT, a master’s in engineering physics and fluid mechanics from UC San Diego, and a PhD in oceanography from the Scripps Institution of Oceanography.

In this episode of Astrophysics for All, I’m joined by Dr. Rosanna Ruggeri, a cosmologist and honorary research fellow at the University of Queensland. We explore how scientists map the large-scale structure of the universe, what dark energy is, and why understanding it is key to predicting the universe’s ultimate fate. Dr. Ruggeri shares her journey working with cutting-edge instruments like DESI and the Vera Rubin Observatory, and explains how curiosity, coding, and persistence shape a career in science.