equinox
Enable an AI agent to identify an equinox, assess the reliability and local relevance of its timing, and decide which seasonal labels, observations or schedules it can support.
Bundle → Layer → Finding → Questions Filled
5 bundles · 9 layers · 16 findings · 27 questions
Equinox identity Establishes which solar crossing is being represented and separates the astronomical event from related names and observances.
Crossing and occurrence
Identifies the event through its astronomical criterion, crossing direction and occurrence year.
Identified solar crossing
Record the intended crossing and year, including whether the reference denotes one occurrence or the recurring event class.
- Does this reference identify a particular year's equinox or equinoxes as a recurring class? definition
- Is the intended crossing northward or southward, and what evidence resolves ambiguous labels such as 'spring equinox'? definition
Neighbouring event boundaries
Separates equinox identity from solstice, equilux and cultural-event identity.
Equinox reference boundary
Record whether a cited date or label actually refers to the astronomical crossing, a local daylight condition or an associated observance.
- Does the cited date denote the solar crossing, local equal day and night, or a celebration linked to the equinox? boundary
- Which related records should be linked while preserving their separate identities? boundary
Event time and evidence Makes the adopted equinox instant traceable, comparable and appropriately precise.
Timing convention
Captures the conventions required to interpret a calculated or published equinox time.
Interpretable event instant
Record the event time together with its time scale, astronomical criterion and stated precision.
- What equinox instant is supplied, in which time scale, and with what stated precision or uncertainty? measurement
- Which reference frame and treatment of solar position define the crossing in this source? definition
Timing support and disagreement
Assesses the provenance of event times and whether apparent discrepancies affect the intended use.
Supported timing selection
Retain the consulted source and explain selection among candidate times without silently discarding disagreement.
- Which consulted publication or reproducible calculation supports each candidate equinox time? provenance
- After accounting for time scales and rounding, what discrepancy remains and does it exceed the task's timing tolerance? measurement
- Which estimate may be adopted for this task, and what unresolved limitation must accompany it? action
Local and seasonal meaning Relates one astronomical instant to local calendars, seasonal conventions and daylight expectations.
Calendar and hemisphere
Derives local date and seasonal language from explicit contextual choices.
Contextual event label
Record how the occurrence is expressed for a particular time zone, calendar, hemisphere and seasonal convention.
- What local date and time correspond to the adopted instant in the requested time zone and calendar? measurement
- Which hemisphere and seasonal convention justify a spring or autumn label, or make either label unsuitable? boundary
Daylight interpretation
Controls conclusions about local daylight that may be drawn from the equinox.
Local daylight claim
Distinguish the astronomical crossing from claims about measured day length, referring local daylight calculations to their own evidence.
- Is the requested claim about the equinox instant or about equal daylight and darkness at a specified location? boundary
- What location, horizon, atmospheric assumptions and sunrise/sunset definitions support any associated daylight estimate? measurement
- Should the agent attach a separate equilux or daylight record before answering the local claim? action
Equinox-based decisions Determines how the identified and supported event may be used in schedules, observations and seasonal rules.
Status and scheduling
Relates the event instant to the current time and an explicit scheduling policy.
Event-relative action window
Record whether an action follows the astronomical instant, its local calendar date or a deliberate offset.
- Relative to the current time and adopted timing tolerance, is this equinox upcoming, being reached or elapsed? measurement
- Should the action occur at the instant, on its local date, or at a specified offset, and which time zone governs the schedule? action
Observation and seasonal triggers
Checks whether the proposed use follows from the equinox or depends on additional conditions.
Supported equinox use
Record the intended use and the external conditions needed before the event can justify an observation or seasonal action.
- Does the proposed seasonal trigger explicitly use an astronomical boundary, or does it require weather, ecological or cultural evidence? boundary
- For an observing activity, what observable phenomenon is intended and which local conditions must be checked separately? action
- What timing discrepancy or missing contextual information would require deferring or revising the proposed action? action
Evidence and external alignment What the world already says about this thing, gathered so the model can be checked against it.
Reported evidence
Findings from the breadth pass, kept separate from the structural claims.
Kinds and varieties
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Which of these kinds and varieties hold for the sense of equinox this model covers, and on what evidence? provenance
Identifiers and schemes
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Which of these identifiers and schemes hold for the sense of equinox this model covers, and on what evidence? provenance
Standards and regulation
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Which of these standards and regulation hold for the sense of equinox this model covers, and on what evidence? provenance
Real-world use
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Which of these real-world use hold for the sense of equinox this model covers, and on what evidence? provenance
Typical measurements
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Which of these typical measurements hold for the sense of equinox this model covers, and on what evidence? provenance
Failure modes and hazards
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Which of these failure modes and hazards hold for the sense of equinox this model covers, and on what evidence? provenance
Regional variation
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Which of these regional variation hold for the sense of equinox this model covers, and on what evidence? provenance
Neighbouring kinds and how to tell them apart
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Which of these neighbouring kinds and how to tell them apart hold for the sense of equinox this model covers, and on what evidence? provenance
Classifiers Filled
- Family
- Thing Registry
- Category
- Activities and processes
- Entry kind
- thing
- Plane
- ACT
- Domain
- ACT.ACT
What it is Filled
An equinox is either of the two instants in a tropical year when the apparent geocentric ecliptic longitude of the Sun is 0° or 180°, so the Sun's centre lies in Earth's equatorial plane and the ecliptic intersects the celestial equator at the Sun.
In scope
- Identification of a particular equinox by year and direction of solar crossing
- Predicted or retrospectively calculated event time, with its reference conventions and uncertainty
- Evidence supporting an equinox identification and reconciliation of competing time estimates
- Translation of the event instant into local dates and hemisphere-dependent seasonal labels
- Assessment of whether the event supports a proposed observation, seasonal boundary or scheduling rule
Out of scope
- Solstices and other astronomical events with different defining conditions
- Equilux dates and the full calculation of local sunrise, sunset and daylight duration
- Weather, climate and ecological season transitions
- Religious festivals, civic holidays and cultural observances associated with an equinox
- General orbital mechanics, ephemeris production and timekeeping infrastructure
Why it exists Filled
Enable an AI agent to identify an equinox, assess the reliability and local relevance of its timing, and decide which seasonal labels, observations or schedules it can support.
Distinguishing features Filled
- An equinox concerns a solar crossing of the celestial equator; a solstice concerns an extremum in the Sun's north-south seasonal position.
- An equinox is an event instant under a stated astronomical convention, rather than an entire calendar day or season.
- An equinox does not require exactly equal daylight and darkness at an observer's location; that local condition belongs to equilux.
- The same equinox receives opposite spring or autumn labels in the Northern and Southern Hemispheres, so a season name alone cannot identify it.
- A celebration named for an equinox is a separate event whose scheduled date need not coincide with the astronomical instant.
What robots and AI may and may not do Filled
Must not
- Present equinoxes as days of exactly equal day and night everywhere.
- Mix up calendar dates across time zones.
- Mock festivals tied to equinoxes.
Only with a human decision
- Setting official dates for events tied to equinoxes.
May
- Report equinox dates and times from astronomical sources, with time zone.
- Explain equinoxes in general terms.
Moral aspects Filled
- Many cultures hold festivals at equinoxes.
- Accurate science matters.
Who is affected
- Cultural communities
- Students
Owners Filled
Steward
Nobody owns it; astronomical bodies publish the times.
Master systems
- Astronomical almanacs
Links to other meta-models Filled
parent
- Q11483816 - registry parent class
- Q14795564 - registry parent class
- Q751989 - registry parent class
What else AI and robots need to interact with it Filled
Identity and identifiers required Filled
- Vercy registry: vr.tr.equinox
- Wikidata: Q1315 (https://www.wikidata.org/wiki/Q1315)
Direct properties not applicable Not applicable
- Crossing direction: northward across the celestial equator | southward across the celestial equator | unresolved
- Occurrence year: year with an explicitly named calendar
- Event instant: timestamp with declared time scale, precision and uncertainty where available
- Astronomical definition used: documented event criterion, reference frame and treatment of solar position
- Timing evidence: links to a consulted ephemeris, published event table or documented calculation
- Temporal status: upcoming | within the adopted event-time tolerance | elapsed | unresolved
- Local calendar expression: event instant mapped to a named time zone and calendar
- Seasonal interpretation: hemisphere and named seasonal convention mapped to a seasonal label, or no applicable label
Plane ACT: no invented physical properties.
Recognition not applicable Not applicable
Not applicable
The exact equinox instant has no distinctive visual appearance and requires astronomical calculation or measurement to identify.
Capabilities and actions required Filled
- Resolve a year and crossing direction to a particular equinox occurrence.
- Compare candidate event times and retain a supported estimate at a precision appropriate to the task.
- Translate the event instant into local dates and create reminders using an explicit offset or scheduling window.
- Assign a seasonal label when the hemisphere and seasonal convention support it.
- Assess an equinox-related observation plan using separately supplied location, horizon and daylight information.
- Flag claims that confuse the equinox with equal daylight, a weather transition or an associated celebration.
Hazards and failure modes required Filled
- Treating an equinox as a guarantee of equal daylight and darkness can produce inaccurate lighting or observation schedules.
- Applying one hemisphere's seasonal labels globally can mislead agricultural or environmental planning.
- Observing the Sun without suitable eye protection can cause permanent eye injury.
Standards and interfaces not applicable Not applicable
Not applicable
No generally applicable product standard or regulation governs an equinox as an astronomical event.
Context of use required Filled
- Equinoxes provide astronomical reference points for seasonal calendars and descriptions of Earth's annual motion.
- Their timings support astronomy education and observation planning, while local seasonal names depend on the hemisphere.
Sources Filled
- Equinox - Civil dates, seasonal naming, the equal-day-and-night misconception, and the distinction from equilux.
- Explanatory Supplement to the Astronomical Almanac, 3rd edition - Specialist definition of the equinox as a solar-longitude event, mean versus true equinox, and the equinox as a celestial-reference origin.
- Astronomical Algorithms, 2nd edition - Computation of equinox instants from solar longitude, tropical-year spacing, and practical date ranges.
- IAU 2006 Resolution B1: Adoption of the P03 Precession Theory and Definition of the Ecliptic - Current IAU treatment of precession, the ecliptic, and the moving equinox as a reference-frame concept.
- Wikidata item Q1315: equinox - identity and sense of the item
Open questions
- Does registry entry vr.tr.equinox intend Earth's astronomical equinox, a broader planetary event class, or another meaning that explains its ACT / ACT.ACT placement?
- Does an existing Vercy world model already own equinox identity or seasonal astronomical events, requiring a link rather than a separate publication?
- Which astronomical definition and reference conventions should govern the model when consulted sources use different equinox calculation criteria?
- Which timing sources, historical range and future prediction range can be supported, and what precision is defensible across those ranges?
- Which seasonal naming conventions and equatorial cases must the model support without imposing a spring/autumn interpretation?
Machine files
Provenance
thing registry research (pass 2) · unreviewed
Built from: models/things/publications/thing-q1315/spec.json