1 astronomical unit
1 AULength · definition
The quantity is exact as entered. Comparisons use the clearly stated specimen, model or nominal measurement.
Length & distance
Just how long is 1 astronomical unit?
Solar neighbourhood
1 AU
1 astronomical unit
The quantity is exact as entered.
1 AULength
0 - shared origin
Earth–Sun distance
The Earth–Sun distance, or astronomical unit, is the standard measure of separation between Earth and the Sun used in astronomy.
1 AUDistance
0 - shared origin
Both rulers start at the same zero and share one linear scale. Artwork keeps its original proportions. A ruler represents the selected distance or a measurement not visible in this view.
A little perspective
1 astronomical unit is approximately equal to the Earth–Sun distance.
Measurements, assumptions & sources +
1 astronomical unit
Length: 1 AU; definition.
The quantity is exact as entered. Comparisons use the clearly stated specimen, model or nominal measurement.
Earth–Sun distance
Distance: 1 AU; definition.
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.
Measurement details
Why these numbers?
Compare 1 astronomical unit with the Earth–Sun distance. The notes below explain how each value was chosen.
Earth–Sun distance
1 AUDistance · definition
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.
- Comparing
- Length ↔ Distance
- Relative size
- 1 astronomical unit is approximately equal to the Earth–Sun distance.
How to read the visual
The diagram uses the recorded measurements. Details outside the marked spans do not set the scale.
This comparison follows the selected length only; other dimensions may differ.
1.496 × 10¹¹ mmetres
4.9081 × 10¹¹ ftfeet
92,956,000 mimiles
1.5813 × 10⁻⁵ lylight-years
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