Astronomical Unit
An astronomical unit (AU) is a unit of distance used in astronomy to describe the average distance between the Earth and the Sun. It equals about 149.6 million kilometers (or about 93 million miles). The AU is useful for measuring distances within our solar system, such as the distance from Earth to other planets. For example, Mars is about 1.5 AU from the Sun. Using the AU makes it easier to understand and compare distances between planets without dealing with very large numbers. The symbol for astronomical unit is "AU".
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
No conversions available for length.