In the 1920s, a Russian biologist studying onion roots made a surprising discovery: underground, down in the darkness, it seemed like the cells inside the onion roots were making their own … light. The “onion root experiment” went on to become something of a cult classic in science, and eventually the biologically-made light was dubbed “biophotons.” In the ensuing century, biophoton discoveries moved from onion roots to bacteria, frog embryos, and humans. Today, scientist Nirosha Murugan is on a career-defining journey to learn more about the light. As she and her colleagues study this mysterious phenomenon, they find themselves racing from question to question, wondering what gives off light, where it might be coming from, and what, if anything, it could tell us about life, disease, and even death. Correction: In this episode, when Nirosha spoke about her melanoma study, she misstated the lab animal involved in the study. It was mice. EPISODE CREDITS: Hosted by - Molly Webster Reported by - Molly Webster Produced by - Sarah Qari with help from - Molly Webster Fact-checking by - Natalie Middleton EPISODE CITATIONS: Videos - The “ Life Flash ” video! Note that fluorescent dye was added to the experiment, by the researchers, to enhance the zinc sparks ( https://www.youtube.com/watch?v=b9tmOyrIlYM ) Articles - T he Onion Root Experiment ( https://www.brmi.online/gurwitsch ) Enjoy this Wikipedia rabbit-hole about Fritz Albert Popp ( https://zpr.io/nxJFcAMvZkBz ) Original Paper on zinc sparks ( https://zpr.io/GfbazBqU3e3y ) at the time of fertilization, a moment referred to as the “life flash” Read more about the “death flash,” ( https://zpr.io/TqG3mcCGYEgQ ) and other end-of-life phenomenon, as reported by medical caregivers Research from Nirosha’s lab on photon emissions ( https://zpr.io/mtpbwSeY4iEp ) and brain activity Research from Nirosha’s lab on biophoton emission ( https://zpr.io/3in9LSmzW6m5 ) and cancer diagnosis Signup for our newsletter!! It includes short essays, recommendations, and details about other ways to interact with the show. Sign up (https://radiolab.org/newsletter)! Radiolab is supported by listeners like you. Foundational support for Radiolab was provided by the Alfred P. Sloan Foundation.