# Gravity Particles Should Be Everywhere. So why are they Impossible to Find? Source: https://www.youtube.com/watch?v=UFXiFfj058U Recap page: https://rapidrecap.app/video/UFXiFfj058U Generated: 2026-01-13T21:36:35.042+00:00 --- ## Quick Overview Detecting the graviton appears fundamentally impossible through current experimental paradigms, as proposed methods either require detectors sensitive beyond the Planck length, leading to inevitable black hole formation, or demand colliders vastly larger than anything feasible to overcome gravity's extreme weakness. **Key Points:** - Freeman Dyson speculated in 2012 that the universe conspires to make graviton detection impossible, either practically due to outlandish experimental requirements or fundamentally due to black holes or the quantum vacuum. - Detecting a single graviton using a LIGO-like interferometer requires measuring a length difference of the order of a single Planck length, which Heisenberg uncertainty dictates necessitates creating a black hole with the measuring apparatus. - To produce gravitons via particle collision, a collider the size of 3 light years in diameter would be needed to reach the billion Joule energy required to match gravity's coupling strength to other forces, contrasting with the LHC's millionth of a Joule collision energy. - The cross-section for a graviton-electron interaction is proportional to the square of the Planck length, making absorption detection extremely unlikely, even if solar emissions (4 per meter squared per second) or emissions from neutron stars were utilized. - The Gertsenshtein effect, where a strong magnetic field transforms gravitons into detectable photons, is shut down by vacuum polarization, which causes spontaneous creation of matter-antimatter pairs in the required strong magnetic field. - Neutrino noise poses a massive obstacle; any feasible graviton source interacting with matter produces $10^{34}$ times more neutrinos than gravitons, making signal distinction practically impossible. **Context:** The video explores the challenge of confirming the quantum nature of gravity by detecting the graviton, the hypothesized quantum particle of gravity, which is necessary to unify quantum mechanics with Einstein's general relativity. This pursuit involves examining methods proposed for detecting gravitons, contrasting them with successful detection techniques for other fundamental particles like photons, and referencing the skeptical analysis provided by physicist Freeman Dyson in his 2012 Poincare prize lecture. ## Detailed Analysis The necessity of a theory of quantum gravity requires finding the graviton, the quantum particle making up spacetime, similar to how photons constitute electromagnetism. The transcript details two broad approaches to detection: measuring the gravitational effect of a single graviton or treating gravitons like other particles via high-energy collisions. The first approach, using a LIGO-like detector, fails fundamentally because measuring a length difference at the Planck length—the required precision—involves an uncertainty relationship that demands the measuring device's components become massive and close enough to form a black hole, preventing measurement by definition. The second approach, particle collision, requires reaching interaction energies around a billion Joules to make gravity's coupling constant comparable to other forces; this necessitates a particle accelerator around 3 light years in diameter, far exceeding the LHC. Even if created, detecting these massless gravitons via an equivalent photoelectric effect is thwarted by their incredibly small cross-section with electrons. Attempts to use natural, high-flux sources like the Sun (emitting about 4 gravitons per meter squared per second) or stellar remnants like neutron stars are overwhelmed by a factor of $10^{34}$ neutrino noise. Finally, the Gertsenshtein effect, which relies on transforming gravitons into photons in a strong magnetic field, is inhibited because the required field strength causes vacuum polarization, disrupting the necessary wave resonance. While some scenarios are deemed fundamentally impossible (black hole formation), others are merely astonishingly difficult, leaving a slim possibility open for new, smarter experiments. ### Graviton Detection Context - Gravitons are the quantum particle of gravity needed for quantum gravity theories like string theory and loop quantum gravity - Freeman Dyson expressed pessimism about detection in 2012 due to experimental impossibility or fundamental barriers. ### LIGO-Scale Graviton Measurement Failure - Detecting a single graviton requires sensitivity to a length difference of one Planck length - Heisenberg uncertainty principle dictates that achieving this precision results in the measuring device forming a black hole. ### Particle Collider Approach Requirements - Producing gravitons requires collision energies of about a billion Joules to strengthen the weak coupling constant - A collider matching the LHC's magnets would need to be 3 light years in diameter to reach this energy. ### Absorption Detection Limitations - The cross-section for a graviton to kick an electron out (gravito-electric effect) is proportional to the square of the Planck length, making it extremely unlikely - Solar emissions provide about 4 gravitons per meter squared per second, but they interact once every billion years. ### The Neutrino Problem - For any viable source, detectors will register $10^{34}$ neutrinos for every single graviton interaction, making separation practically impossible. ### Gertsenshtein Effect Obstruction - The proposed conversion of gravitons to photons in a strong magnetic field is prevented because the necessary field strength induces vacuum polarization and spontaneous matter-antimatter pair creation. ### Conclusion and Future Outlook - Detection is fundamentally impossible in some cases (black hole formation) but astonishingly difficult in others - New proposals combining LIGO-like interferometry with quantum detectors offer a potential path forward for a future episode.