Barleycorn
A barleycorn is an old English unit of length, traditionally based on the length of a grain of barley. It is defined as exactly 1/3 of an inch or approximately 8.47 millimeters.
Historically, the barleycorn was used for measuring small lengths and was also the basis for the inch, which was originally considered to be three barleycorns long. It played a role in various traditional measurements, including shoe sizing in English-speaking countries, where shoe sizes were sometimes expressed in barleycorn units.
Although obsolete as a formal unit, the barleycorn remains culturally significant, especially in shoe sizing systems.
Summary:
1 barleycorn = 1/3 inch ≈ 8.47 mm
Based on the length of a grain of barley
Used historically in small measurements and shoe sizing
Mostly of historical and cultural interest today
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.
No conversions available for length.