Astronomical Unit (a.u.) of Length
The astronomical unit (a.u.) is a unit of length used primarily in astronomy to describe distances within our solar system. It is defined as the average distance between the Earth and the Sun.
Key facts:
1 astronomical unit ≈ 149,597,870.7 kilometers (about 93 million miles)
Used to measure distances between planets and other objects in the solar system
Provides a convenient scale for expressing space distances that are too large for kilometers but too small for light-years
The astronomical unit helps astronomers communicate and calculate orbits, planetary positions, and space missions with clarity and precision.
Gigameter
A gigameter (Gm) is a unit of length in the metric system, equal to 1 billion meters (1 Gm = 10⁹ meters). Gigameters are used to measure very large distances, often within the solar system. For example, the average distance from Earth to the Sun is about 150 gigameters, or 1 astronomical unit (AU). While not commonly used in everyday life, gigameters are helpful in astronomy and space science to describe distances between planets or other celestial bodies.