Question

why do astronauts use au instead of kilometers

Answer 1

Astronauts use the astronomical unit (AU) instead of kilometers because it is a more convenient unit of measurement when dealing with distances in space. The astronomical unit is defined as the average distance between the Earth and the Sun, which is approximately 149.6 million kilometers. Using the astronomical unit allows astronauts to easily compare and calculate distances between planets and other celestial bodies without having to convert between different units of measurement. Additionally, distances in space are often very vast, and using smaller units like kilometers would result in very large numbers that can be cumbersome to work with.