For general access to the Wolfram Knowledgebase, use entities of type Comet instead of CometData.


gives the value of the specified property for the comet entity.


gives a list of property values for the specified comet entities.


gives the specified annotation associated with the given property.


  • CometData[] gives a list of all comet entities.
  • CometData["Properties"] gives a list of available properties.
  • The specified entity in CometData can be an Entity, EntityClass, entity canonical name, or list thereof.
  • The specified property can be an EntityProperty, EntityPropertyClass, property canonical name, or list of properties.
  • Properties that do not apply or are not known in a particular case are indicated by Missing[].
  • Properties include:
  • "Age"age
    "AlphanumericName"alphanumeric name
    "AlternateNames"alternate names
    "Aphelion"largest distance from the Sun
    "Apoapsis"largest distance from orbit center
    "ApoapsisTime"next apoapsis time
    "ApoapsisTimeLast"last apoapsis time
    "ApparentAltitude"apparent altitude
    "ApparentMagnitude"apparent magnitude
    "AscendingNodeLongitude"longitude of ascending node
    "AverageDistanceFromEarth"average distance from Earth
    "AverageOrbitDistance"average orbit distance
    "AverageOrbitVelocity"average orbit velocity
    "AverageVelocityAroundSun"average heliocentric velocity
    "BooleanRise"above the horizon
    "DailyTimeAboveHorizon"daily time above horizon
    "DestructionDate"destruction date
    "Diameter"average diameter
    "DiscoveryYear"discovery year
    "DistanceFromEarth"distance from Earth
    "DistanceFromSun"distance from Sun
    "EarthMOID"Earth minimum orbit intersection distance
    "EccentricAnomaly"eccentric anomaly
    "Eccentricity"orbital eccentricity
    "EquatorialDiameter"equatorial diameter
    "EquatorialRadius"equatorial radius
    "GalacticLatitude"galactic latitude
    "GalacticLongitude"galactic longitude
    "GreenwichHourAngle"Greenwich hour angle
    "HeliocentricLatitude"heliocentric latitude
    "HeliocentricLongitude"heliocentric longitude
    "HelioCoordinates"heliocentric XYZ coordinates
    "IAUName"IAU name
    "Inclination"orbital inclination
    "LocalHourAngle"local hour angle
    "MajorAxis"major axis
    "MeanAnomaly"mean anomaly
    "MeanMotion"mean motion
    "MinorAxis"minor axis
    "NuclearMagnitudeParameter"nuclear magnitude parameter
    "NuclearMagnitudeSlopeParameter"nuclear magnitude slope parameter
    "OrbitCenter"orbit center
    "OrbitCircumference"orbit circumference
    "OrbitPath"orbit path
    "OrbitPeriod"orbital period
    "OrbitRules"orbit rules
    "Periapsis"nearest distance from orbit center
    "PeriapsisArgument"argument of periapsis
    "PeriapsisLongitude"longitude of periapsis
    "PeriapsisTime"next periapsis time
    "PeriapsisTimeLast"last periapsis time
    "Perihelion"nearest distance from the Sun
    "PrimaryDesignation"primary designation
    "Radius"average radius
    "RetrogradeApparentMotionQuery"apparent direction
    "RightAscension"right ascension
    "RiseTime"rise time
    "RotationPeriod"rotation period
    "SemimajorAxis"semimajor axis
    "SemiminorAxis"semiminor axis
    "SetTime"set time
    "SiderealHourAngle"sidereal hour angle
    "SolarDay"solar day
    "SphereOfInfluenceRadius"sphere of influence radius
    "SurfaceArea"surface area
    "TotalMagnitudeParameter"total magnitude parameter
    "TotalMagnitudeSlopeParameter"total magnitude slope parameter
    "TrueAnomaly"true anomaly
  • Some properties are available for CometData as a whole and can be given using the form CometData[property]. Such properties include:
  • "Entities"all available entities
    "EntityCount"total number of available entities
    "Classes"all available entity classes
    "EntityClassCount"total number of available entity classes
    "SampleEntities"list of sample entities
    "SampleEntityClasses"list of sample entity classes
    "EntityCanonicalNames"list of all entity canonical names
    "PropertyCanonicalNames"list of all property canonical names
    "EntityClassCanonicalNames"list of all entity class canonical names
    "RandomEntities"pseudorandom sample entities
    {"RandomEntities",n}n pseudorandom entities
    "RandomEntityClasses"pseudorandom sample entity classes
    {"RandomEntityClasses",n}n pseudorandom entity classes
  • The following annotations can be used in the third argument of CometData[entity,property,annotation]:
  • "Qualifiers"the list of possible qualifiers for the property
    "QualifierValues"the list of possible values that can be given to each qualifier
    "DefaultQualifierValues"the list of default values for the property's qualifiers
    "Description"a brief textual description of the property
    "Definition"a detailed textual definition of the property
    "Source"source information for the property
    "Date"the date associated with the entity-property value (if any)
    "PhysicalQuantity"the physical quantity associated with the entity-property value
    "Unit"the unit associated with the entity-property value
    "EntityAssociation"an association of entities and entity-property values
    "PropertyAssociation"an association of properties and entity-property values
  • If a function is provided as an annotation, it will be used to aggregate the result data. Typical aggregation functions include:
  • Minthe minimum value
    Maxthe maximum value
    Meanthe mean value
    Commonestthe most frequently occurring value
    Medianthe median value
    Totalreturns the total
    Lengththe number of elements


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Basic Examples  (5)

Use for discovery:

Click for copyable input

Find the current distance to a comet:

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Find the next periapsis time of a comet:

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Get a list of available classes of comets:

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Rank comets in a class by orbit period:

Click for copyable input

Scope  (2)

Neat Examples  (1)

Introduced in 2014