{"id": "card_rel_mass_energy", "kind": "reference", "title": "Mass-energy — E = m c^2", "body": "The electron's rest energy is m_e c^2 = 0.511 MeV (sealed). Mass and energy are the same thing, and because c^2 is enormous a tiny mass is a vast energy. Mass IS rest energy - it enters the Hamiltonian as the energy a body has even at rest.", "source": {"label": "Narrow Highway — relativity", "url": "", "authority_tier": "engine_derived"}, "shelf": "codex", "box": "relativity", "bands": ["relativity", "pillar", "mass_energy", "one map"], "subject": "Mass-energy — E = m c^2", "connections": [{"to_card_id": "card_floor_relativity", "relationship": "part_of", "evidence": "a pillar of relativity (Mass-energy)"}, {"to_card_id": "card_floor_the_hamiltonian", "relationship": "connects_at", "evidence": "E = m c^2: mass is rest energy, part of the Hamiltonian"}], "author": "engine", "created_at": 0.0, "updated_at": 0.0, "visibility": "public", "lifecycle_stage": "public", "volatility": "permanent", "surface": "secular", "generated": false, "call": "codex.relativity", "facets": {"subject": ["mass_energy", "one map", "pillar"]}, "presentation": {"glyph": "•", "kind_label": "relativity", "by": "Narrow Highway — relativity", "authority": "engine_derived", "posted": "", "standing": ""}, "neighbors": [{"id": "card_floor_relativity", "title": "Relativity — many frames, one invariant", "relationship": "part of", "why": "a pillar of relativity (Mass-energy)", "href": "/card/card_floor_relativity", "resolved": true}, {"id": "card_floor_the_hamiltonian", "title": "The Hamiltonian — the law of the flow", "relationship": "connects at", "why": "E = m c^2: mass is rest energy, part of the Hamiltonian", "href": "/card/card_floor_the_hamiltonian", "resolved": true}], "house": {"door": "FIND", "kind": "card", "trail": "connections", "seal": "/card/card_rel_mass_energy", "next_step": {"do": "follow a connection: what this card rests on, and what rests on it", "door": "FIND", "tool": "card_connections", "params": {"id": "card_rel_mass_energy"}}, "ends": "a verdict or a card · the trail · a seal · one next step"}}