The unit used to measure large distances between objects in our solar system is the Astronomical Unit (AU).

Here's why it's used:

* Convenient Scale: Using kilometers or miles to express distances between planets would result in incredibly large and unwieldy numbers. The AU provides a more manageable scale.

* Based on Earth's Orbit: One AU is defined as the average distance between the Earth and the Sun. This makes it a natural and relatable unit for measuring distances within our solar system.

Here's a quick comparison:

* 1 AU = 149.6 million kilometers = 93 million miles

So, for example, Mars is about 1.5 AU from the Sun, while Jupiter is about 5.2 AU from the Sun.