Finding the Missing Matter Between Galaxies - Isabel Medlock

How do you tell the age of a star that barely seems to age? And could the answer help us find another Earth?In this episode, I sit down with Professor Marcel Agüeros, astronomer at Columbia University and President of the American Astronomical Society, to explore how the spin and magnetic activity of stars can reveal their ages—and why that matters in the search for life beyond our Solar System.We also dive into time-domain astronomy, how the Vera C. Rubin Observatory is essentially creating a ten-year movie of the night sky, and why white dwarfs give astronomers a natural laboratory for physics we can’t recreate on Earth. And then there’s the big question: how close are we to finding Earth 2.0? Professor Agüeros explains why finding an Earth-like planet may be only half the challenge—and why the age and activity of its star could determine whether life ever had a chance to emerge. We finish with his advice for young people interested in astronomy, why there’s no need to have your entire career mapped out, and what it means to find a community in science that you genuinely want to be part of.

What did the universe look like before the first galaxies - and how can we reconstruct an era we can barely observe?I speak with Dr Anshuman Acharya, a postdoctoral fellow at the Berkeley Center for Cosmological Physics at UC Berkeley, about the epoch of reionization, when the first galaxies began transforming the early universe.Dr Acharya explains how astrophysicists build cosmological simulations to recreate the evolution of the universe, how machine learning can help researchers compare thousands of possible models with telescope observations, and why the incredibly faint 21-cm signal from neutral hydrogen could provide a new window into the formation of the earliest galaxies. The conversation also explores international collaboration in astrophysics, Dr Acharya’s move from the Max Planck Institute to UC Berkeley, and his advice for students: explore widely, build transferable skills, and don’t feel pressured to have your entire scientific path figured out from the beginning.

Have you ever wondered how astronomers discover something they've never seen before?In this episode of Astrophysics for All, I'm joined by Dr. Kishalay De, Assistant Professor of Astronomy at Columbia University, whose research explores some of the universe's most spectacular "cosmic fireworks"—from exploding stars and stellar mergers to the first convincing evidence of a star swallowing one of its own planets.We talk about what it's like to stumble across a discovery no one was expecting, why astronomers use everything from infrared light to gravitational waves to study the universe, and how the next generation of observatories could uncover phenomena we've never even imagined. We also discuss the growing role of AI in astronomy, the importance of strong foundations in physics, and why some of the biggest scientific breakthroughs begin with curiosity rather than certainty.Whether you're interested in astronomy, physics, or simply curious about how discoveries are made, I hope you enjoy the conversation!

Professor Robert Simcoe is the Director of the MIT Kavli Institute for Astrophysics and Space Research, and one of the world's leading astrophysicists on spectroscopy and the early universe.In this episode of Astrophysics for All, Rob explains how astronomers use light to study the first stars and galaxies that formed after the Big Bang. He shares why he likes to say that "if a picture is worth a thousand words, then a spectrum is worth a thousand pictures," and reveals how a beam of starlight can tell us about the composition, motion, and history of objects billions of light-years away.We also discuss what it's like to design and build cutting-edge astronomical instruments, the excitement of detecting photons that have travelled for over 13 billion years, and how telescopes allow us to look back in time and uncover the universe's origin story.

How do you study something you can't see?In this episode, Yale astronomy PhD candidate Isabel Medlock explains how astronomers use powerful computer simulations and mysterious fast radio bursts to investigate the invisible universe. We discuss the cosmic web, the search for the universe's missing matter, and how scientists can effectively "rebuild" the cosmos inside a computer to understand how it evolved over billions of years.We also chat about life as a computational cosmologist, the importance of making science accessible, and what advice Isa would give to students hoping to pursue astrophysics themselves.

Are galaxies truly eternal, or do they have lifecycles just like living things?In this episode of Astrophysics for All, I speak with Dr Jesse van de Sande, astrophysicist and lecturer at UNSW, about how galaxies form, evolve, and eventually stop producing new stars. We explore the idea of "zombie galaxies," the future collision between the Milky Way and Andromeda, and how astronomers use the motions of stars to reconstruct events that occurred billions of years ago.Jesse also explains how cutting-edge techniques such as integral field spectroscopy allow researchers to map galaxies in unprecedented detail, and shares insights into life as a professional astrophysicist.

Professor Sara Seager is one of the world's leading exoplanet scientists and a professor of planetary science and physics at the Massachusetts Institute of Technology. Her research has helped shape the modern search for planets beyond our Solar System and the quest to discover life elsewhere in the universe.In this episode of Astrophysics for All, Professor Seager discusses how astronomers use spectroscopy to study exoplanet atmospheres, what scientists mean by a "biosignature", and why proving the existence of extraterrestrial life is far more difficult than many people realise. She also explains the science behind Project Starshade, reflects on the revolutionary impact of the James Webb Space Telescope, and shares why Venus has re-emerged as one of the most intriguing worlds in our Solar System.Along the way, Professor Seager offers valuable advice for students interested in astrophysics and STEM, discussing confidence, curiosity, and the importance of building connections throughout your scientific journey. 

In this episode of Astrophysics for All, I’m joined by Professor Marla Geha, Professor of Astronomy and Physics at Yale University and an award-winning educator whose research focuses on dwarf galaxies and dark matter.We explore how some of the faintest and smallest galaxies in the universe could help answer some of cosmology’s biggest questions. Professor Geha explains how astronomers detect invisible dark matter through the motion of stars, why dwarf galaxies are so important for understanding galaxy formation, and how modern digital sky surveys are transforming astronomy.

Astronomy has long captivated human curiosity, but how can it reshape our lives and communities? Dr. Emma Cain Louden is a passionate astrophysicist with a PhD from Yale University, and serves as the president of Slooh, a platform that democratises access to astronomy by allowing people around the world to use remotely operated telescopes. Her work bridges the gap between complex scientific concepts and relatable experiences, making astronomy relevant to a wider audience.

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.