Why do astronomers use astronomical units (AU) instead of kilometers (km)?(1 point)
AU is used in astronomy, while km is used in physics.
There are no km in outer space, only AU.
AU is used for spacing, while km is used for length.
Large distances are easier to express in AU than in km.
Large distances in the solar system can be easier to express in astronomical units (AU) than in kilometers (km). This is because AU is a unit of measurement that is based on the average distance between the Earth and the Sun, which is about 149.6 million kilometers. By using AU, astronomers can easily relate and compare large distances within the solar system without dealing with extremely large numbers in km.
Additionally, the use of AU allows for a more intuitive understanding of the scale and spacing of objects within the solar system. For example, the average distance of the Earth from the Sun is approximately 1 AU, while the average distance of Mars from the Sun is about 1.5 AU. This provides a simple way to understand relative distances and to compare the spacing of planetary orbits.
While kilometers are certainly used in astronomy for more specific measurements and calculations, such as determining the size of objects or distances within a given planet or moon, AU is often preferred for discussions and measurements involving larger distances within the solar system.