{"schema":"https://ver.cy/schemas/card/1.0.0","id":"vr.tr.gamma","code":"thing-q827951","url":"https://ver.cy/models/thing/q827951/","name":"gamma","alternateNames":[],"kind":"thing","status":"published","version":"0.2.0-wave.3","language":"en","classifiers":{"family":"Thing Registry","category":"Cross-cutting context","entryKind":"thing","plane":"XCT","domain":["XCT.QTY"],"industry":[],"navPath":"","tags":[],"facets":{}},"whatItIs":"A dimensionless eclipse parameter describing centrality at greatest eclipse, expressed in Earth's equatorial radii: for a solar eclipse, it measures the minimum distance between the Moon's shadow axis and Earth's centre; for a lunar eclipse, it measures the minimum distance between the Moon's centre and Earth's shadow axis, with a sign assigned according to the eclipse catalogue's convention.","purpose":"Let an agent explain eclipse gamma, interpret its magnitude and sign using the conventions of a cited eclipse catalogue, and distinguish it from magnetic-field units, gamma radiation, the gamma function and display gamma.","scope":{"in":[],"out":[],"boundaries":[]},"distinguishingFeatures":["Gamma describes the centrality of an eclipse through shadow geometry.","Its magnitude expresses a distance in Earth's equatorial radii.","Its sign distinguishes the side on which the Moon's shadow axis passes relative to Earth's centre for solar eclipses, or the Moon's centre passes relative to Earth's shadow axis for lunar eclipses, under the catalogue's convention.","Solar and lunar eclipse interpretations require their respective shadow geometries."],"structure":{"bundles":[{"id":"define","name":"Define","description":"Definition.","layers":[{"id":"definition","name":"Definition","description":"Definition and value.","findings":[{"id":"definition-finding","name":"Definition","description":"Definition.","questions":[{"text":"What is the gamma as a unit, and how does it relate to the tesla and gauss?","kind":"definition"},{"text":"Is the question about the magnetic unit, the microgram or another use of gamma?","kind":"boundary"}]}]},{"id":"conversion","name":"Conversion","description":"Conversion.","findings":[{"id":"conversion-finding","name":"Conversion","description":"Conversion.","questions":[{"text":"How are gammas converted to nanoteslas and gauss?","kind":"measurement"},{"text":"Which entry fits tesla?","kind":"action"}]}]}]},{"id":"use","name":"Use","description":"Use in geophysics.","layers":[{"id":"geomagnetism","name":"Geomagnetism","description":"Geomagnetism.","findings":[{"id":"geomagnetism-finding","name":"Geomagnetism","description":"Geomagnetism.","questions":[{"text":"How is the gamma used in geomagnetic observatories and space physics?","kind":"provenance"},{"text":"Which entry fits geomagnetic field?","kind":"action"}]}]},{"id":"surveys","name":"Surveys","description":"Magnetic surveys.","findings":[{"id":"surveys-finding","name":"Surveys","description":"Surveys.","questions":[{"text":"How are magnetic anomaly surveys reported in gammas or nanoteslas?","kind":"provenance"},{"text":"Which references are standard?","kind":"provenance"}]}]}]},{"id":"context","name":"Context","description":"History and SI.","layers":[{"id":"history","name":"History","description":"History.","findings":[{"id":"history-finding","name":"History","description":"History.","questions":[{"text":"When was the gamma introduced, and why is it still used informally?","kind":"provenance"},{"text":"Which sources are cited?","kind":"provenance"}]}]},{"id":"si","name":"SI","description":"SI recommendation.","findings":[{"id":"si-finding","name":"SI","description":"SI.","questions":[{"text":"What does the SI recommend, and how do journals treat the gamma?","kind":"provenance"},{"text":"Which entry fits non-SI units?","kind":"action"}]}]}]},{"id":"senses","name":"Senses","description":"Other senses.","layers":[{"id":"mass","name":"Mass","description":"Gamma as microgram.","findings":[{"id":"mass-finding","name":"Mass","description":"Mass.","questions":[{"text":"How was gamma used for the microgram, and where does it persist?","kind":"provenance"},{"text":"Which entry fits microgram?","kind":"action"}]}]},{"id":"symbols","name":"Symbols","description":"Gamma in physics.","findings":[{"id":"symbols-finding","name":"Symbols","description":"Symbols.","questions":[{"text":"What other quantities does the symbol gamma denote in physics?","kind":"provenance"},{"text":"Which entry fits the specific quantity?","kind":"action"}]}]}]}]},"agentConduct":{"may":["Explain eclipse gamma and its relationship to shadow centrality.","Report gamma values from astronomical catalogues with the eclipse type and sign convention identified."],"mustNot":["Confuse eclipse gamma with magnetic-field units, gamma radiation, the gamma function or display gamma.","Treat gamma alone as sufficient to determine local eclipse visibility.","Use gamma alone to claim that viewing the Sun is safe."],"requiresHuman":["Announcing new eclipse calculations on behalf of a research team."]},"ethics":{"considerations":["Clear definitions and conventions prevent misleading eclipse information.","Public eclipse information should distinguish geometric predictions from viewing safety."],"affectedParties":["Astronomers use gamma in eclipse analysis.","Educators and the public rely on accurate eclipse explanations."]},"owners":{"steward":"Nobody owns the parameter; astronomical catalogue maintainers document its values and conventions.","roles":[],"masterSystems":["Astronomical eclipse catalogues record gamma values."]},"relations":[{"target":"Q107715","type":"parent","note":"registry parent class"},{"target":"physical quantity","type":"related","note":"in registry terms, as a unit"},{"target":"nanotesla","type":"related","note":"exactly"},{"target":"magnetic survey","type":"related","note":"and geomagnetism"},{"target":"gauss","type":"related","note":"the CGS unit"}],"interaction":{"identity":{"applicability":"required","items":["Vercy registry: vr.tr.gamma","Wikidata: Q827951 (https://www.wikidata.org/wiki/Q827951)","symbol: gamma Greek letter"]},"properties":{"applicability":"not-applicable","items":["value: 1 nT","Earth surface field: about 25000-65000 gamma"]},"recognition":{"applicability":"optional","items":["Eclipse catalogues may label this parameter as gamma.","Solar eclipse diagrams can show the Moon's shadow axis and its closest approach to Earth's centre, while lunar eclipse diagrams can show the Moon's centre and its closest approach to Earth's shadow axis.","The parameter is a numerical description of geometry rather than a directly visible feature.","Not a visible object; a unit symbol in survey data."]},"capabilities":{"applicability":"required","items":["define the unit","relay uses in geophysics","note other senses","route to SI units"]},"hazards":{"applicability":"required","items":["Confusing eclipse gamma with other meanings of gamma gives incorrect interpretations.","Treating gamma as a magnetic-field measurement assigns the wrong physical meaning.","Ignoring sign conventions or eclipse type can misrepresent shadow geometry.","Gamma alone does not establish local visibility or safe viewing conditions."]},"interfaces":{"applicability":"required","items":["SI Brochure recommending tesla and nanotesla","Geophysical survey reporting conventions"]},"context":{"applicability":"required","items":["Expressing small magnetic field values.","gamma as magnetic flux density unit","gamma as microgram in older chemistry","gamma as other symbols in physics such as the Lorentz factor, a separate sense"]}},"sources":[{"title":"Wikidata item Q827951: gamma","url":"https://www.wikidata.org/wiki/Q827951","note":"identity and sense of the item"},{"title":"Wikipedia: Gamma (eclipse)","url":"https://en.wikipedia.org/wiki/Gamma_%28eclipse%29","note":"general description of the item"}],"openQuestions":["Should the microgram sense be a separate entry?","How should geophysical conventions be linked?","How should the Greek letter symbol be recorded?"],"resources":{"spec":"/models/things/publications/thing-q827951/spec.json"},"provenance":{"origin":"thing registry research (pass 2)","builtFrom":["models/things/publications/thing-q827951/spec.json"],"providers":["Claude"],"researchStatus":"unreviewed","generatedAt":"2026-09-13T01:44:01Z","builder":"tools/build_cards.py@1.0.0"},"completeness":{"sections":{"classifiers":"filled","whatItIs":"filled","purpose":"filled","distinguishingFeatures":"filled","structure":"filled","agentConduct":"filled","ethics":"filled","owners":"filled","relations":"filled","interaction.identity":"filled","interaction.properties":"not-applicable","interaction.recognition":"filled","interaction.capabilities":"filled","interaction.hazards":"filled","interaction.interfaces":"filled","interaction.context":"filled","sources":"filled"},"notes":{"_gate":"Published through the thing publication gate 1.0 on 2026-10-07T12:16:34+00:00: completeness 1.00; sense: Wikidata description; 2 live sources; review by codex: pass","interaction.properties":"Plane XCT: no invented physical properties."},"score":1.0}}