What is the deepest level of reality? In this Quanta explainer, Vijay Balasubramanian, a physicist at the University of Pennsylvania, takes us on a journey through space-time to investigate what it’s made of, why it’s failing us, and where physics can go next. Explore black holes, holograms, “alien algebra,” and more space-time geometry: https://www.quantamagazine.org/the-unraveling-of-space-time-20240925/ 00:00 - The Planck length, an intro to space-time 1:23 - Descartes and Newton investigate space and time 2:04 - Einstein's special relativity 2:32 - The geometry of space-time and the manifold 3:16 - Einstein's general relativity: space-time in four dimensions 3:35 - The mathematical curvature of space-time 4:57 - Einstein's field equation 6:04 - Singularities: where general relativity fails 6:50 - Quantum mechanics (amplitudes, entanglement, Schrödinger equation) 8:32 - The problem of quantum gravity 9:38 - Applying quantum mechanics to our manifold 10:36 - Why particle accelerators can't test quantum gravity 11:28 - Is there something deeper than space-time? 11:45 - Hawking and Bekenstein discover black holes have entropy 13:54 - The holographic principle 14:49 - AdS/CFT duality 16:06 - Space-time may emerge from entanglement 17:44 - The path to quantum gravity -------- - VISIT our website: https://www.quantamagazine.org - LIKE us on Facebook: / quantanews - FOLLOW us Twitter: / quantamagazine Quanta Magazine is an editorially independent publication supported by the Simons Foundation: https://www.simonsfoundation.org