Astronomical Unit (AU)
An astronomical unit of length defined as exactly 149,597,870,700 meters, representing the mean distance from Earth to the Sun.
Governing formula
1 AU = 149,597,870,700 m ≈ 1.496 × 10¹¹ m
SI unit
Astronomical Units (AU)
In depth
Used as the standard distance scale within the Solar System and exoplanetary system orbits. 1 AU light travel time is approximately 499 seconds (~8.31 minutes).
Examples in the real world
Jupiter orbiting the Sun at a mean distance of ~5.2 AU, and Neptune at ~30 AU.