International Atomic Time

E21211

atomic time scale time standard

International Atomic Time is a high-precision time standard based on the combined output of atomic clocks worldwide, serving as the fundamental reference for modern civil and scientific timekeeping.

Aliases (2)

Galileo System Time ×1
TAI time scale ×1

Statements (46)

Predicate	Object
instanceOf	atomic time scale → time standard →
abbreviation	TAI →
accuracy	on the order of 10^-16 with primary standards →
basedOn	atomic clocks → cesium atomic clocks →
category	metrology → timekeeping →
closelyRelatedTo	TT → Terrestrial Time →
continuousWithNoJumps	true →
coordinatedBy	International Bureau of Weights and Measures →
definedBy	International System of Units → SI second →
epoch	1958-01-01T00:00:00 →
epochReference	geocenter →
formalAdoption	1960s →
frameOfReference	Earth geoid →
governingOrganization	CIPM → International Bureau of Weights and Measures → surface form: "Comité International des Poids et Mesures"
introduced	late 1950s →
language	multilingual designation →
leapSecondsApplied	no →
maintainedBy	International Bureau of Weights and Measures → surface form: "BIPM" International Bureau of Weights and Measures → surface form: "Bureau International des Poids et Mesures"
referenceFor	Coordinated Universal Time → Coordinated Universal Time → surface form: "UTC" modern civil timekeeping → scientific timekeeping →
relationToUTC	UTC = TAI plus or minus leap seconds →
scaleUnit	second →
secondDefinition	9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium-133 atom →
shortName	International Atomic Time → surface form: "TAI time scale"
stability	high frequency stability →
successorOf	ephemeris time →
timeScaleType	continuous time scale → uniform time scale →
usedFor	astronomy → fundamental physics experiments → geodesy → satellite navigation → spacecraft tracking →
usesDataFrom	national metrology institutes → over 400 atomic clocks worldwide → primary frequency standards → secondary frequency standards →

Referenced by (7)

Full triples — surface form annotated when it differs from this entity's canonical label.

Coordinated Universal Time → basedOn → International Atomic Time →

Coordinated Universal Time → coordinatedWith → International Atomic Time →

Greenwich Mean Time → relatedStandard → International Atomic Time →

National Standard Time → relatedStandard → International Atomic Time →

International Atomic Time → shortName → International Atomic Time →

surface form: "TAI time scale"

PTP → timeScale → International Atomic Time →

Galileo satellite navigation system → timeStandard → International Atomic Time →

surface form: "Galileo System Time"