Catherine Heymans on the lighter side of the dark universe

Episode Summary

Executive Summary: Astrophysicist Catherine Haymans discusses her pioneering work mapping dark matter through gravitational lensing, her efforts to make science accessible via comedy and outreach, and her role as the first woman Astronomer Royal for Scotland. The interview also covers her long-Covid setback, her book on existential questions about reality, and her hopes for future breakthroughs on dark matter, dark energy, and physics outreach.

Main Topics: Dark matter and dark energy research (Priority: 5/5): Haymans explains that ordinary matter is only a small fraction of the universe, while dark matter and dark energy remain poorly understood but crucial to cosmic structure and expansion. Gravitational lensing and mapping the invisible universe (Priority: 5/5): She describes how distortions in distant galaxy images reveal the location and distribution of dark matter, enabling her to create dark matter maps and infer cosmological properties. Science communication through comedy (Priority: 4/5): Haymans and collaborator Joe Zuntz use stand-up comedy to reach audiences beyond the usual science converts, aiming to change misconceptions that science is dull, inaccessible, or not for girls. Career path shaped by teaching and telescopes (Priority: 4/5): Early passion for maths, a transformative physics teacher, university choices, and hands-on observing experiences at Edinburgh and Australia shaped her move from theory toward observational cosmology. Leadership, representation, and outreach in Scotland (Priority: 4/5): As the first female Astronomer Royal for Scotland, Haymans is building the Scottish Youth Telescope Network to bring telescope experiences to remote outdoor centers and inspire children. Long Covid, resilience, and philosophical inquiry (Priority: 3/5): A severe long-Covid illness forced her to step back from leadership roles and led to a new book project exploring whether her reality could be simulated, while reframing how she approaches work and life. Future of cosmology and next-generation surveys (Priority: 5/5): She highlights Euclid and the Vera Rubin Observatory as complementary projects that will generate unprecedented sky surveys and potentially clarify dark matter and dark energy.

Key Arguments: Dark matter matters because it shapes galaxy formation and the universe’s structure, even though its nature is still unknown. Dark energy is inferred from the universe’s accelerating expansion, implying physics beyond current models. Gravitational lensing is the key observational method for locating dark matter by measuring tiny distortions in galaxy shapes. Better telescopes and bigger surveys require increasingly sophisticated analysis, but they also enable stronger cosmological conclusions. Comedy can be a powerful tool for science engagement because it reaches people who would not attend a lecture and can challenge stereotypes. Visible role models and outreach matter for changing who studies physics, especially among girls and young students. Combining Euclid’s space-based clarity with Rubin’s wide, deep ground-based imaging will be essential for the next leap in dark-universe research. After major illness, focusing on the 'next best thing' can help people maintain purpose and joy despite limitations.

Data Points: Universe composition known to physics: Less than 5% - Ordinary matter (people, Earth, Sun, stars) makes up less than 5% of the universe. Dark sector share of universe: About 95% - Haymans says the rest of the universe is dark matter and dark energy. Dark energy share of universe: About 70% - She describes dark energy as making up roughly 70% of the universe. Birth year: 1978 - Haymans was born in Hitchin, north of London. Distance of galaxy light studied: About 10 billion light years - Her lensing work maps distant galaxies whose light has traveled for billions of years. Supercluster distance: 2.6 billion light years away - The Hubble-based study of a galactic supercluster in Vancouver. Survey scale increase: 100 times bigger - The Canada-France-Hawaii telescope survey was 100 times larger than previous Hubble work. Survey processing time: 5 years - Her team rewrote the analysis method and completed the large survey over five years. Hubble camera upgrade: Fourth servicing mission - She studied data after Hubble was fitted with the Advanced Camera for Surveys. Current timeline for Rubin data: Weeks away - At the time of the interview, first data from the Vera Rubin Observatory was imminent. Rubin project duration: Over 10 years - Rubin will repeatedly image the night sky for more than a decade to create a movie of the universe. Astronomer Royal for Scotland: 11th holder; first woman - Haymans was appointed in 2021. Long Covid duration: Three years on - She says she is improved but still recovering several years after falling ill in March 2022. Retirement horizon: Another 20 years - She expresses hope that dark matter/dark energy will be solved before she retires.

Pivotal Quotes: "the other 95%, is dark. And we don't understand it." — Catherine Haymans: Explaining why dark matter and dark energy are central problems in cosmology. "there is absolutely nothing more joyful than being able to make people laugh." — Catherine Haymans: Describing why she and Joe Zuntz perform science comedy to reach wider audiences. "focus on what is the next best thing that you can do" — Catherine Haymans: Advice drawn from her long-Covid recovery and career adaptation.

Implications: Her work shows how cosmology is advancing through massive surveys, while outreach and representation remain vital. The next decade could finally clarify dark matter and dark energy, and her recovery story underscores adaptability in science careers.