Final answer:
An astronomical unit (AU) is the average distance from Earth to the Sun, approximately 150 million kilometers. It's a standard unit of measurement used by astronomers to describe distances within our solar system, making calculations and explanations more manageable.
Step-by-step explanation:
An astronomical unit (AU) is a unit of length that is roughly equal to the average distance between the Earth and the Sun. This distance is about 1.5 × 108 kilometers or approximately 93 million miles. The AU is a convenient measure used by astronomers to express and compare distances within our solar system. When measuring distances in the vast expanse of space, using the astronomical unit helps to simplify the numbers and make them more manageable. For example, the distance from Earth to Jupiter can be expressed as about 5.2 AU rather than approximately 778 million kilometers (483 million miles).
The length of 1 AU has been determined with great precision to be 149,597,870,700 meters, equivalent to about 8.3 light-minutes. By using AUs, calculations and explanations involving distances in space become more relatable and easier to understand. The use of AUs also eliminates the large, cumbersome numbers that would otherwise be involved in describing distances between astronomical objects in our solar system.