Final answer:
The astronomical unit (AU) is the average Earth-Sun distance. A light-year is a unit of distance larger than an AU. Astronomers use the metric system for calculations and measure distances to stars in light-years.
Step-by-step explanation:
The astronomical unit (AU) is not the distance across the solar system. It is actually the average distance between the Earth and the Sun, which is about 150 million kilometers.
A light-year is a unit of distance that is larger than an astronomical unit. It is the distance that light travels in one year, which is about 9.5 trillion kilometers.
Astronomers use the metric system for calculations, including measuring distances. The metric system is preferred in scientific calculations because of its simplicity and consistency.
Scientific notation is used to represent both very large numbers and very small numbers. It allows for the representation of numbers in a compact and convenient way.
The distances to stars are measured in light-years because they are incredibly far away. A light-year represents the distance that light travels in one year, which is a much more suitable unit for measuring interstellar distances than kilometers or astronomical units.
A light-year is not the time that light takes to travel one astronomical unit. It is a measure of distance, not time.