Earth–Sun distance
The Earth–Sun distance, or astronomical unit, is the standard measure of separation between Earth and the Sun used in astronomy.
Also known as: earth to sun, earth sun distance, distance to the sun, au, astronomical unit
How big is it?
1 AU away
Distance · definition
A little perspective
About 389 times the distance of Earth–Moon distance.
Earth–Moon distance: The Earth–Moon distance is the average space between the centres of the Earth and the Moon.
Measurements, assumptions & sources +
Earth–Sun distance
One astronomical unit is exactly 149,597,870,700 m. It is a useful Earth–Sun orbital scale, not the separation at every instant. Light takes about 8 minutes 19 seconds to cross it.
NIST — 2022 CODATA fundamental constants
The marked distance is calibrated. Unmeasured illustration details are representative.
Earth–Moon distance
Average centre-to-centre distance. The Moon’s orbit is not a circle.
NASA — Earth and Moon by the numbers
The marked distance is calibrated. Unmeasured illustration details are representative.
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Why this measurement?
Why we use 1 AU
For comparison, this page uses distance. The record labels this value definition, so the stated convention rather than an inferred average controls the comparison.
One astronomical unit is exactly 149,597,870,700 m. It is a useful Earth–Sun orbital scale, not the separation at every instant. Light takes about 8 minutes 19 seconds to cross it.
The marked horizontal span follows the named feature; transparent margins and unmeasured details do not alter it. How calibrated comparisons work →
Recorded properties
Earth–Sun distance dimensions and measurements
| Property | Selected value | Recorded range | Basis |
|---|---|---|---|
| 1 AU | Not recorded | definition | |
| 8.317 min | Not recorded | definition |
Around this scale
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Sources and method
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The source records and measurement method remain available for inspection.
- NIST — 2022 CODATA fundamental constantsRecommended constants with uncertainties; exact SI definitions are distinguished from measured constants.
More ways to see it
Curated comparisons
There’s always another scale
Follow your curiosity.
SpaceEarth12,740 kmEarth is the rocky planet on which we live and the third planet from the Sun.
SpaceSun1,391,000 kmThe Sun is the star at the centre of the Solar System.SpaceEarth–Moon distance384,400 kmThe Earth–Moon distance is the average space between the centres of the Earth and the Moon.SpaceNeptune’s orbital distance30.11 AUNeptune’s orbital distance is the average separation between Neptune and the Sun.
SpaceRed giant0.465 AUA red giant is a star that has expanded and cooled after exhausting the hydrogen in its core.SpaceBetelgeuse6.511 AUBetelgeuse is a red supergiant star in the constellation Orion that changes in brightness over time.
SpaceSirius A2,379,000 kmSirius A is the brighter main-sequence star in the Sirius binary system.
SpaceKuiper Belt outer orbit50 AUThe Kuiper Belt is a region of the Solar System beyond Neptune containing many icy bodies and dwarf planets.