Criteria For Being Classified As A Moon?

[carole]

Reading the following item about Jupiter's newly discovered moons prompted me to ask the question: what are the criteria for defining an orbiting object as a moon?

http://www.space.com/scienceastronomy/astronomy/jupiter_satellite_020516.html

These items are only 1.2 to 2.5 miles in diameter, what's the smallest diameter for a moon before it goes down a notch to 'orbiting debris'?

Carole

 

[DerekH16]

I suspect the rule of thumb is 'orbiting a planet and big enough to be seen as a single, separate object'.

 

[_schnor]

It's just bodies of various sizes in a definite, fixed orbit around the parent planet - I don't think there is a definite size limit to them, it's just that the smaller they are the harder they are to see.

The size differences are dodgy, as pluto is smaller than most moons, so it's a bit of a mess really