Sabine Hossenfelder

Sabine Hossenfelder is a German theoretical physicist and one of science YouTube's most distinctive voices. Holding a PhD in theoretical physics from Goethe University Frankfurt, she spent two decades as an academic researcher in quantum gravity and the foundations of physics before becoming prominent online. Since 2006 she has maintained the popular-science blog Backreaction, and from around 2020 her YouTube channel has become a major platform for rigorous, often contrarian commentary on physics and science media.

What distinguishes Hossenfelder from other science communicators is her willingness to critique her own field. Her book Lost in Math: How Beauty Leads Physics Astray (2018) provoked significant debate in the physics community by arguing that physicists' pursuit of mathematically elegant theories—supersymmetry, string theory, naturalness—has led the field astray from empirical testability. This is not anti-science scepticism; it is internal scientific criticism backed by more than 80 peer-reviewed publications.

Her YouTube videos and blog posts regularly push back against physics hype in media coverage: overclaimed results from particle physics experiments, speculative cosmological claims, and pop-science misrepresentations of quantum mechanics. Her second book, Existential Physics (Viking, 2022), extended this rigour to questions of meaning and consciousness. She has also written for Scientific American, Nautilus, The New York Times, and The Guardian, and has been funded in part by YouTube revenue to support ongoing independent research in quantum gravity.