{"schema":"https://ver.cy/schemas/card/1.0.0","id":"vr.tr.redshift","code":"thing-q76250","url":"https://ver.cy/models/thing/q76250/","name":"redshift","alternateNames":["spectroscopic redshift","cosmological redshift","photometric redshift","gravitational redshift"],"kind":"thing","status":"published","version":"0.2.0-wave.4","language":"en","classifiers":{"family":"Thing Registry","category":"Cross-cutting context","entryKind":"thing","plane":"XCT","domain":["XCT.QLT"],"industry":[],"navPath":"","tags":[],"facets":{}},"whatItIs":"The increase in wavelength of light or other radiation from a source, shifting spectral lines toward the red, caused by the source moving away in the Doppler effect, by the expansion of the universe in cosmological redshift, or by climbing out of a gravitational field in gravitational redshift, measured precisely from spectra as spectroscopic redshift or estimated from colours as photometric redshift; redshift is the main tool for measuring distances and the expansion of the universe.","purpose":"Let an agent explain redshift and its causes, relay measurement methods and their use in cosmology from astronomy references, describe key results such as Hubble s law, and distinguish redshift from blueshift, from reddening by dust and from the everyday sense of red colour.","scope":{"in":[],"out":[],"boundaries":[]},"distinguishingFeatures":["Wavelength shift","Three causes","Distance proxy","Cosmology foundation"],"structure":{"bundles":[{"id":"understand","name":"Understand","description":"What redshift is.","layers":[{"id":"definition","name":"Definition","description":"Definition and causes.","findings":[{"id":"definition-finding","name":"Definition","description":"Definition.","questions":[{"text":"What is redshift, and how do Doppler, cosmological and gravitational redshift differ from blueshift and dust reddening?","kind":"definition"},{"text":"Is the question about the concept, a cause, measurement or cosmology?","kind":"boundary"}]}]},{"id":"formula","name":"Formula","description":"Definition and scale.","findings":[{"id":"formula-finding","name":"Formula","description":"Formula.","questions":[{"text":"How is z defined, and what do redshifts of 0.1, 1, 10 and 1100 mean?","kind":"definition"},{"text":"Which entry fits the cosmic distance ladder?","kind":"action"}]}]}]},{"id":"measure","name":"Measure","description":"Measurement.","layers":[{"id":"spectroscopic","name":"Spectroscopic","description":"Spectroscopic redshift.","findings":[{"id":"spectroscopic-finding","name":"Spectroscopic","description":"Spectroscopic.","questions":[{"text":"How are redshifts measured from spectral lines?","kind":"measurement"},{"text":"Which references are standard?","kind":"provenance"}]}]},{"id":"photometric","name":"Photometric","description":"Photometric redshift.","findings":[{"id":"photometric-finding","name":"Photometric","description":"Photometric.","questions":[{"text":"How are redshifts estimated from colours, and how accurate are they?","kind":"measurement"},{"text":"Which sources are cited?","kind":"provenance"}]}]}]},{"id":"cosmology","name":"Cosmology","description":"Cosmology.","layers":[{"id":"expansion","name":"Expansion","description":"Expansion.","findings":[{"id":"expansion-finding","name":"Expansion","description":"Expansion.","questions":[{"text":"How did Hubble and later surveys use redshift to establish and measure cosmic expansion?","kind":"provenance"},{"text":"Which entry fits the expansion of the universe?","kind":"action"}]}]},{"id":"surveys","name":"Surveys","description":"Redshift surveys.","findings":[{"id":"surveys-finding","name":"Surveys","description":"Surveys.","questions":[{"text":"What have redshift surveys such as SDSS revealed about large-scale structure?","kind":"provenance"},{"text":"Which entry fits redshift survey?","kind":"action"}]}]}]},{"id":"context","name":"Context","description":"Gravity and history.","layers":[{"id":"gravity","name":"Gravity","description":"Gravitational redshift.","findings":[{"id":"gravity-finding","name":"Gravity","description":"Gravity.","questions":[{"text":"How does gravitational redshift test general relativity, from Pound-Rebka to GPS?","kind":"provenance"},{"text":"Which entry fits tests of general relativity?","kind":"action"}]}]},{"id":"history","name":"History","description":"History.","findings":[{"id":"history-finding","name":"History","description":"History.","questions":[{"text":"How was redshift discovered and interpreted by Slipher, Hubble and Lemaitre?","kind":"provenance"},{"text":"Which entry fits the history of cosmology?","kind":"action"}]}]}]}]},"agentConduct":{"may":["Explain Doppler, cosmological and gravitational redshift.","Convert between redshift, velocity and distance and state the model used.","Report measured redshifts with their catalogue and uncertainty."],"mustNot":["Present a distance from redshift without the cosmological model it depends on.","Treat preliminary claims of record redshifts as confirmed.","Confuse redshift with the colour of an object."],"requiresHuman":["Publishing claims about new record distances or cosmological results."]},"ethics":{"considerations":["Overstated results erode public trust in science.","Credit for discoveries belongs to the teams that made them."],"affectedParties":["Astronomers","Students and the public"]},"owners":{"steward":"Nobody owns the phenomenon; survey teams and catalogues hold the measurements.","roles":[],"masterSystems":["Astronomical redshift catalogues"]},"relations":[{"target":"Q107715","type":"parent","note":"registry parent class"},{"target":"physical quantity","type":"related","note":"in registry terms"},{"target":"Doppler effect","type":"related","note":"for moving sources"},{"target":"Hubble s law","type":"related","note":"to measure expansion"},{"target":"blueshift","type":"related","note":"a shift toward shorter wavelengths"}],"interaction":{"identity":{"applicability":"required","items":["Vercy registry: vr.tr.redshift","Wikidata: Q76250 (https://www.wikidata.org/wiki/Q76250)"]},"properties":{"applicability":"not-applicable","items":["definition: z = (observed minus emitted wavelength) over emitted formula","highest confirmed galaxy redshift: above 13 z - 2020s","CMB redshift: about 1100 z","Hubble s law: 1929 year"]},"recognition":{"applicability":"optional","items":["Wavelength increase of light","Doppler, cosmological, gravitational; spectroscopic and photometric redshift","Blueshift is the opposite; dust reddening dims blue light without shifting lines","Not a visible object; spectral lines displaced toward longer wavelengths."]},"capabilities":{"applicability":"required","items":["explain causes","relay measurement","describe cosmological use","distinguish related concepts"]},"hazards":{"applicability":"required","items":["Confusing redshift with reddening","Treating cosmological redshift as a simple Doppler shift","Photometric redshift errors"]},"interfaces":{"applicability":"required","items":["No regulation; astronomical data standards for redshift catalogues"]},"context":{"applicability":"required","items":["Measuring motion, distance and expansion.","Doppler redshift from motion","cosmological redshift from expansion","gravitational redshift","spectroscopic redshift measurement","photometric redshift estimation","redshift surveys of galaxies"]}},"sources":[{"title":"Wikidata item Q76250: redshift","url":"https://www.wikidata.org/wiki/Q76250","note":"identity and sense of the item"},{"title":"Wikipedia: Redshift","url":"https://en.wikipedia.org/wiki/Redshift","note":"general description of the item"}],"openQuestions":["Should cosmological and gravitational redshift be separate primary entries?","How should astronomy references be linked?","The registry entry has merged aliases naming causes and methods; should they be split off?"],"resources":{"spec":"/models/things/publications/thing-q76250/spec.json"},"provenance":{"origin":"thing registry research (pass 2)","builtFrom":["models/things/publications/thing-q76250/spec.json"],"providers":["Claude"],"researchStatus":"unreviewed","generatedAt":"2026-09-13T13:26:56Z","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 2026-10-06T19:52:02+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}}