{"id": "card_n_cda0b1e1a364", "kind": "note", "title": "Fusion — why the stars shine", "body": "Four hydrogens weigh more than one helium; the difference is sunlight. Sealed from\nthe measured masses: 4·m(H) − m(He-4) = 0.0287 u → 26.73 MeV per helium forged: https://narrowhighway.com/s/8a5e89ab13bc499f39240c64360d90c34a65a291c91c73fcac4fc976131b17c5 .\nThat 0.7% toll on hydrogen's mass, paid over ~10 billion years, is the sun's entire budget\n— every green leaf runs on the deficit. The honest boundary: the ENERGY seals from the mass\ntables; the RATE (why the sun burns slowly instead of exploding) is quantum tunnelling\nthrough the Coulomb wall — empirical cross-sections, the reason fusion power is hard and\nstars are patient.", "source": {"label": "Concordance assay — 2026-07-09", "url": "https://narrowhighway.com/s/8a5e89ab13bc499f39240c64360d90c34a65a291c91c73fcac4fc976131b17c5", "ref": "nuclear_dig", "authority_tier": "engine_derived"}, "shelf": "science", "box": "nuclear", "bands": ["fusion", "sun", "4h to helium", "26.7 mev", "proton-proton chain", "stars", "mass defect"], "connections": [], "author": "engine", "created_at": "2026-07-10T01:19:38.918200+00:00", "updated_at": "2026-07-10T01:19:38.918200+00:00", "visibility": "public", "lifecycle_stage": "public", "volatility": "permanent", "surface": "secular", "metrics": {"paperclips_count": 0, "helpful_count": 0, "not_helpful_count": 0, "cite_count": 0, "walks_through_count": 0, "flagged_count": 0}, "source_hash": "13bf18bbc8513562025de7b41c19556390d27e5f8b21a9dcf7205ab6b4417d93"}