Answer:
Astronomical units (AU) are used to compare the distance between "objects in the solar system".
Explanation:
- For planet size, distance comparison metric measurement including astronomical units are used.
- Most objects in space are far away where astronomical units is insufficient to measure. Light years are used for measuring distances to objects in space.
- One astronomical unit = 93 million miles = 150 million kilometres
- Another unit of distance is called parsec which is 3.26 light years.