New Lex Fridman Insight: Harry Cliff: Particle Physics and the Large Hadron Collider
Sent June 11, 2026
Key Insights
- The Large Hadron Collider (LHC) accelerates particles to 99.9999991% of light speed using powerful magnets in a 27 km tunnel.
- Particles are ripples in quantum fields, not fundamental units, with the Higgs boson discovered via LHC proton collisions.
- The Future Circular Collider is planned to be 100 km in circumference, costing about 30 billion euros, targeting completion by 2070.
- B quarks oscillate between matter and antimatter, providing insights into why the universe is predominantly matter.
- Supersymmetry, a theory predicting super partners for particles, remains unproven after a decade of LHC data.
How the conversation moved
The conversation begins with Harry Cliff explaining the Large Hadron Collider (LHC) as a monumental scientific instrument designed to explore the fundamental nature of particles. He describes how the LHC accelerates particles to near-light speeds in a 27-kilometer tunnel, using powerful magnets to maintain their paths. This setup allows physicists to recreate conditions similar to those just after the Big Bang, providing insights into fundamental forces and particles. Cliff emphasizes that particles are not the smallest units of matter but rather excitations in quantum fields, challenging traditional views of particle physics.
Cliff's main argument revolves around the LHC's role in confirming the existence of the Higgs boson, a particle that provides mass to other particles through the Higgs field. This discovery was achieved by creating high-energy collisions that disturb the Higgs field, allowing the boson to be detected. He explains that the LHC's design, with its powerful magnets and precise engineering, was crucial in achieving this milestone. The conversation also touches on the LHC's limitations, such as its inability to detect supersymmetric particles, which are hypothesized to stabilize the Higgs field.
While Lex Fridman does not directly challenge Cliff's explanations, he raises the issue of the LHC's limitations in discovering new particles, particularly in relation to supersymmetry. Cliff acknowledges this challenge, noting that despite a decade of data collection, no evidence of supersymmetric particles has been found. This lack of discovery raises questions about the validity of supersymmetry as a theoretical framework, which has been a cornerstone in particle physics for explaining the Higgs mechanism without fine-tuning.
The discussion concludes with a look towards future projects like the Future Circular Collider, which aims to be even larger and more powerful than the LHC. Cliff discusses the potential for machine learning to enhance data analysis, which could lead to new discoveries. However, the conversation leaves open the question of whether these future endeavors will uncover new physics or if the current theoretical models will need significant revision. The episode ends with an acknowledgment of the beauty and complexity of physics, as well as the collaborative nature of scientific discovery.
Surprising moments
In-depth
Large Hadron Collider
- The LHC's 27 km circumference and near-light speed particle acceleration.
- Use of powerful magnets to maintain particle paths.
- Discovery of the Higgs boson through high-energy collisions.
Quantum Fields
- Particles as ripples in quantum fields, not fundamental units.
- Higgs boson's role in mass acquisition for particles.
Future Collider Projects
- Future Circular Collider's 100 km size and 30 billion euro cost.
- Potential for new physics beyond the LHC.
Matter-Antimatter Asymmetry
- B quarks' oscillation between matter and antimatter.
- The mystery of the universe's matter dominance.
Supersymmetry and Theoretical Physics
- Supersymmetry predicts super partners for particles.
- Lack of evidence challenges the theory's validity.
Notable Quotes
The electron is not like a little planet orbiting the atom. It's this spread out, wibbly wobbly wave like thing.
Still open
- Cliff questions whether future collider projects will uncover new physics beyond the current theoretical models.
- The episode leaves open the question of how machine learning might transform data analysis in particle physics.