X-Raying the Earth: Neutrino Tomography at the South Pole

Welcome back to the podcast! Today, we are exploring a groundbreaking new way scientists are looking deep inside our planet. For a century, our understanding of the Earth's interior has relied almost entirely on seismic waves and gravity. But what if we could use cosmic "ghost particles" to scan the Earth instead? In this episode, we dive into a fascinating new study from the IceCube Neutrino Observatory located deep in the glacial ice at the South Pole. Using 10.7 years of data, scientists have successfully mapped the Earth's radial density profile using high-energy muon neutrinos. We discuss how these neutrinos, which usually pass right through matter undetected, become partially blocked by the Earth at extremely high energies (above ~10 TeV). By measuring how these particles are absorbed as they travel through different layers of the planet at different angles, researchers can essentially take a tomographic scan of the Earth's interior using the weak nuclear force. Tune in to hear how this cutting-edge method has been used to independently calculate the Earth's mass and polar moment of inertia, yielding results that are completely consistent with traditional seismology and the Preliminary Reference Earth Model (PREM). We also discuss what this means for the future of planetary science and how next-generation neutrino telescopes will bring even sharper resolution to the hidden layers beneath our feet.Reference mentioned in this episode: Abbasi, R., et al. (IceCube Collaboration). "High-Energy Neutrino Tomography of the Earth’s Interior with IceCube." arXiv:2607.02644v1 (July 2026).Acknowledements: Podcast prepared with Google/NotebookLM. Illustration credits: IceCube Collaboration