Why are Au's used to describe distances in space?

Answer 1

Because the inch, foot, meter, kilometer, and mile are all too small, and the light year is too big.
All of those produce inconvenient numbers when used to measure distances in the solar system.

Mercury's average distance from the sun is:
36,000,000 miles
57,900,000 kilometers,
0.000006124 light year
0.387 AU.

Pluto's average distance from the sun is:
3,670,000,000 miles
5,910,000,000 kilometers
0.0006247 light year
39.46 AU.

Answer 2

Kilometers and miles can be used, but as the distances involved are so large, it becomes difficult to get your head around the huge numbers. Using 1 AU = Earth to sun distance, we can easily appreciate straight away that the 30AU distance from Neptune to Earth is 30 times that of the sun to Earth distance (for example).

Answer 3

Astronomical units (Au) are used to describe distances in space because they provide a convenient way to express large distances within the solar system. 1 Au is defined as the average distance between the Earth and the Sun, which is about 93 million miles. Using Au helps simplify calculations and comparisons when discussing planetary orbits, asteroid distances, and other celestial bodies within our solar system.

Answer 4

Distances in space are so huge that a shorthand has arisen

1 Astronomical unit is approx 100 million miles (distance of Earth to Sun)

A much larger distance is a parsec.

Answer 5

one Astronamical Unit, or AU, is equal to the distance between earth and the sun. (about 93,000,000 miles.)

Answer 6

astronomers created the astronomical unit because planets lie so far

apart that kilometres are not a meaningful way to measure the distances

between them.

Answer 7

It's defined as the earth's average distance from the sun, which makes it a
handy unit for talking about the planets and other things in the solar system.