Hectometer
A hectometer (hm) is a unit of length in the metric system, equal to 100 meters. It is larger than a meter but smaller than a kilometer. While it is part of the official metric system, the hectometer is rarely used in daily life or science. For example, a running track is 400 meters long, which is 4 hectometers. The symbol for hectometer is "hm". Although not commonly seen, it can be useful for measuring medium-range distances, especially when kilometers feel too large and meters too small.
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.