The Spark of Life

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 WebsterReported by - Molly WebsterProduced by - Sarah Qariwith help from - Molly WebsterFact-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 - The 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 caregiversResearch from Nirosha’s lab on photon emissions (https://zpr.io/mtpbwSeY4iEp) and brain activityResearch from Nirosha’s lab on biophoton emission (https://zpr.io/3in9LSmzW6m5) and cancer diagnosisSignup 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. Support Radiolab by becoming a member of The Lab (https://members.radiolab.org/) today. Follow our show on Instagram, Twitter and Facebook @radiolab, and share your thoughts with us by emailing [email protected]. Leadership support for Radiolab’s science programming is provided by the Simons Foundation and the John Templeton Foundation. Foundational support for Radiolab was provided by the Alfred P. Sloan Foundation.

Episode 659 of the Radiolab podcast, hosted by WNYC Studios, titled "The Spark of Life" was published on September 19, 2025 and runs 36 minutes.

September 19, 2025 ·36m · Radiolab

Summary

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 WebsterReported by - Molly WebsterProduced by - Sarah Qariwith help from - Molly WebsterFact-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 - The 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 caregiversResearch from Nirosha’s lab on photon emissions (https://zpr.io/mtpbwSeY4iEp) and brain activityResearch from Nirosha’s lab on biophoton emission (https://zpr.io/3in9LSmzW6m5) and cancer diagnosisSignup 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. Support Radiolab by becoming a member of The Lab (https://members.radiolab.org/) today. Follow our show on Instagram, Twitter and Facebook @radiolab, and share your thoughts with us by emailing [email protected]. Leadership support for Radiolab’s science programming is provided by the Simons Foundation and the John Templeton Foundation. Foundational support for Radiolab was provided by the Alfred P. Sloan Foundation.

Episode Description