H6C17S2.4 Distances in Space: Astronomical Unit
Distances in Space: Astronomical Unit
Miles and kilometers are fine for measuring long distances on Earth, such as the distance from New York to Chicago. Even bigger units are needed to measure vast distances in space.
One such measure is astronomical unit. An astronomical unit equals 150 million km, which is the mean distance from Earth to the Sun. Astronomical unit is abbreviated AU.
If something is 3 AU away from the Sun, then the object is three times farther from the Sun than Earth is. The AU is a convenient unit for measuring distances in the solar system.