Hiranya Peiris on unravelling the story of the universe

In this episode of The Life Scientific, host Jamal Khalili interviews Professor Hiranya Peiris, a pioneering astrophysicist and Professor of Astrophysics 1909 at the University of Cambridge. Peiris shares her journey from a young girl in Colombo, Sri Lanka, inspired by science fiction and the cosmos, to becoming a leading figure in precision cosmology. Her early fascination with the universe—fueled by Stephen Hawking’s A Brief History of Time, a childhood telescope, and mentorship from her engineer mother—led her to pursue science despite challenges as a woman of colour in a male-dominated field. After moving to the UK during the civil war, she overcame academic and financial hurdles to study computer science at Cambridge, then switched to physics after a transformative internship at NASA’s Jet Propulsion Laboratory. Her PhD work at Princeton on the Wilkinson Microwave Anisotropy Probe helped confirm the standard model of cosmology, pinning the universe’s age at 13.8 billion years and revealing that 95% of the cosmos is made of dark matter and dark energy. She later contributed to the Planck mission, providing evidence for cosmic inflation—the rapid expansion of the universe in its first fraction of a second. Now back at Cambridge, Peiris leads a new era of observational cosmology through the Legacy Survey of Space and Time at the Vera Rubin Observatory, using a 3.2-billion-pixel camera to create a time-lapse movie of the universe, mapping dark matter and tracking asteroids. Her work bridges fundamental physics and data-driven discovery, transforming cosmology from speculation into a precision science. Peiris reflects on the emotional and intellectual thrill of scientific discovery, the importance of role models, and her enduring dream of going to space. She emphasizes the power of curiosity, resilience, and the human drive to understand our place in the cosmos. Her story is one of perseverance, inspiration, and the profound beauty of uncovering universal truths through observation, computation, and imagination. The episode closes with a hopeful vision of science as a collective, evolving narrative—where each generation builds on the last, like threads in a cosmic tapestry.