---
title: Template:Infobox/galaxy
canonical_url: https://paxabyssi.com/wiki/Template:Infobox/galaxy
markdown_url: https://paxabyssi.com/wiki/Template:Infobox/galaxy.md
type: wiki-page
namespace: Template
revision_id: 6
revision_view: stable
last_updated: 2026-09-27
license: CC BY-SA 4.0
license_url: https://creativecommons.org/licenses/by-sa/4.0/
summary: "Infobox schema for the Milky Way page and any other galaxy: the fields, their groups, labels and units, as a JSON Schema."
categories:
  - Infobox schemas
---

# Template:Infobox/galaxy

> Source: https://paxabyssi.com/wiki/Template:Infobox/galaxy
>
> Licence: [CC BY-SA 4.0](https://creativecommons.org/licenses/by-sa/4.0/). Text by Pax Abyssi Wiki contributors; history at https://paxabyssi.com/wiki/Template:Infobox/galaxy/history
>
> Revision 6, 27 September 2026

This page holds the JSON Schema for `infobox: type: galaxy`, used by the Milky Way page and any other galaxy (the field list follows SCIENCE_CORPUS 2.9). Every page whose frontmatter names this type is validated against it on save: a schema error blocks a save by a new account or an API client and warns a trusted editor.

Values are flexible so that writers can record what the sources allow. A field may be plain text or a number, a quantity object `{value, unit, min, max, error, source, note}`, or a by-status mapping `{observed, model, sim}` when the measured, inferred and generated values differ. Fields not listed here are allowed and shown under "Other" in the infobox. The `x-pax` block carries display metadata: the groups in order, each group's default provenance tag, and the label and unit for every field.

```json
{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://paxabyssi.com/wiki/Template:Infobox/galaxy",
  "title": "Galaxy",
  "description": "Infobox for the Milky Way page and any other galaxy. Fields follow SCIENCE_CORPUS 2.9.",
  "type": "object",
  "required": [
    "type"
  ],
  "properties": {
    "type": {
      "const": "galaxy"
    },
    "image": {
      "$ref": "#/$defs/fileTitle",
      "description": "Lead image, a File: title."
    },
    "caption": {
      "type": "string"
    },
    "image_caption": {
      "type": "string"
    },
    "hubble_type": {
      "$ref": "#/$defs/field"
    },
    "stars": {
      "$ref": "#/$defs/field"
    },
    "satellite_galaxies": {
      "$ref": "#/$defs/field"
    },
    "central_black_hole": {
      "$ref": "#/$defs/field"
    },
    "oldest_disk_stars_gyr": {
      "$ref": "#/$defs/field"
    },
    "stellar_mass_msun": {
      "$ref": "#/$defs/field"
    },
    "total_mass_msun": {
      "$ref": "#/$defs/field"
    },
    "stellar_disk_diameter_kpc": {
      "$ref": "#/$defs/field"
    },
    "thin_disk_scale_length_kpc": {
      "$ref": "#/$defs/field"
    },
    "thin_disk_scale_height_pc": {
      "$ref": "#/$defs/field"
    },
    "thick_disk_scale_length_kpc": {
      "$ref": "#/$defs/field"
    },
    "thick_disk_scale_height_pc": {
      "$ref": "#/$defs/field"
    },
    "bar_and_bulge_stellar_mass_msun": {
      "$ref": "#/$defs/field"
    },
    "bar_angle_to_sun_centre_line_deg": {
      "$ref": "#/$defs/field"
    },
    "sun_distance_from_centre_kpc": {
      "$ref": "#/$defs/field"
    },
    "sun_height_above_midplane_pc": {
      "$ref": "#/$defs/field"
    },
    "circular_speed_at_sun_km_s": {
      "$ref": "#/$defs/field"
    },
    "galactic_year_myr": {
      "$ref": "#/$defs/field"
    },
    "sim_source": {
      "$ref": "#/$defs/field"
    },
    "physics_engine": {
      "$ref": "#/$defs/field"
    },
    "science_doc": {
      "$ref": "#/$defs/field"
    },
    "rendered_example": {
      "$ref": "#/$defs/field"
    },
    "last_verified": {
      "$ref": "#/$defs/field"
    }
  },
  "additionalProperties": true,
  "$defs": {
    "quantity": {
      "type": "object",
      "description": "A number or range with its unit and provenance.",
      "properties": {
        "value": {
          "type": [
            "number",
            "string",
            "null"
          ]
        },
        "unit": {
          "type": "string"
        },
        "min": {
          "type": [
            "number",
            "string"
          ]
        },
        "max": {
          "type": [
            "number",
            "string"
          ]
        },
        "error": {
          "type": [
            "number",
            "string"
          ]
        },
        "uncertainty": {
          "type": [
            "number",
            "string"
          ]
        },
        "source": {
          "type": "string",
          "description": "observed | model | sim | catalogue | fiction, or a citation."
        },
        "note": {
          "type": "string"
        },
        "as_of": {
          "type": [
            "string",
            "number"
          ]
        }
      },
      "additionalProperties": true
    },
    "byStatus": {
      "type": "object",
      "description": "The same quantity as measured (observed), inferred (model) and generated (sim).",
      "properties": {
        "observed": {
          "$ref": "#/$defs/cell"
        },
        "model": {
          "$ref": "#/$defs/cell"
        },
        "sim": {
          "$ref": "#/$defs/cell"
        },
        "note": {
          "type": "string"
        }
      },
      "additionalProperties": true
    },
    "cell": {
      "anyOf": [
        {
          "type": "string"
        },
        {
          "type": "number"
        },
        {
          "type": "boolean"
        },
        {
          "type": "null"
        },
        {
          "type": "array"
        },
        {
          "$ref": "#/$defs/quantity"
        }
      ]
    },
    "field": {
      "anyOf": [
        {
          "$ref": "#/$defs/cell"
        },
        {
          "$ref": "#/$defs/byStatus"
        },
        {
          "type": "object"
        }
      ]
    },
    "fileTitle": {
      "type": "string",
      "pattern": "^File:"
    },
    "status": {
      "description": "One or more of observed, model, sim, speculative, fiction; or a sentence saying which parts carry which label.",
      "anyOf": [
        {
          "type": "string"
        },
        {
          "type": "array",
          "items": {
            "type": "string"
          }
        }
      ]
    }
  },
  "x-pax": {
    "label": "Galaxy",
    "image_field": "image",
    "caption_field": "caption",
    "groups": [
      {
        "index": "01",
        "title": "Identity",
        "fields": [
          "hubble_type",
          "stars",
          "satellite_galaxies",
          "central_black_hole",
          "oldest_disk_stars_gyr"
        ],
        "provenance": "catalogue"
      },
      {
        "index": "02",
        "title": "Mass and structure",
        "fields": [
          "stellar_mass_msun",
          "total_mass_msun",
          "stellar_disk_diameter_kpc",
          "thin_disk_scale_length_kpc",
          "thin_disk_scale_height_pc",
          "thick_disk_scale_length_kpc",
          "thick_disk_scale_height_pc",
          "bar_and_bulge_stellar_mass_msun",
          "bar_angle_to_sun_centre_line_deg"
        ]
      },
      {
        "index": "03",
        "title": "The Sun's place",
        "fields": [
          "sun_distance_from_centre_kpc",
          "sun_height_above_midplane_pc",
          "circular_speed_at_sun_km_s",
          "galactic_year_myr"
        ]
      },
      {
        "index": "04",
        "title": "Sim",
        "fields": [
          "sim_source",
          "physics_engine",
          "science_doc",
          "rendered_example",
          "last_verified"
        ],
        "provenance": "sim"
      }
    ],
    "fields": {
      "hubble_type": {
        "label": "Hubble type"
      },
      "stars": {
        "label": "Stars"
      },
      "satellite_galaxies": {
        "label": "Satellite galaxies"
      },
      "central_black_hole": {
        "label": "Central black hole"
      },
      "oldest_disk_stars_gyr": {
        "label": "Oldest disk stars",
        "unit": "Gyr"
      },
      "stellar_mass_msun": {
        "label": "Stellar mass",
        "unit": "M☉"
      },
      "total_mass_msun": {
        "label": "Total mass",
        "unit": "M☉"
      },
      "stellar_disk_diameter_kpc": {
        "label": "Stellar disk diameter",
        "unit": "kpc"
      },
      "thin_disk_scale_length_kpc": {
        "label": "Thin disk scale length",
        "unit": "kpc"
      },
      "thin_disk_scale_height_pc": {
        "label": "Thin disk scale height",
        "unit": "pc"
      },
      "thick_disk_scale_length_kpc": {
        "label": "Thick disk scale length",
        "unit": "kpc"
      },
      "thick_disk_scale_height_pc": {
        "label": "Thick disk scale height",
        "unit": "pc"
      },
      "bar_and_bulge_stellar_mass_msun": {
        "label": "Bar and bulge stellar mass",
        "unit": "M☉"
      },
      "bar_angle_to_sun_centre_line_deg": {
        "label": "Bar angle to Sun-centre line",
        "unit": "°"
      },
      "sun_distance_from_centre_kpc": {
        "label": "Sun's distance from the centre",
        "unit": "kpc"
      },
      "sun_height_above_midplane_pc": {
        "label": "Sun's height above the midplane",
        "unit": "pc"
      },
      "circular_speed_at_sun_km_s": {
        "label": "Circular speed at the Sun",
        "unit": "km/s"
      },
      "galactic_year_myr": {
        "label": "Galactic year",
        "unit": "Myr"
      },
      "sim_source": {
        "label": "Sim source"
      },
      "physics_engine": {
        "label": "Physics engine"
      },
      "science_doc": {
        "label": "Science document"
      },
      "rendered_example": {
        "label": "Rendered example"
      },
      "last_verified": {
        "label": "Last verified"
      }
    }
  }
}
```

Categories: [Infobox schemas](https://paxabyssi.com/wiki/Category:Infobox_schemas.md)