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.