How many moons are there in the Solar System?
Short answer: There are more than 200 moons that we know of in the Solar System.
Long answer: We don't have an exact number for two reasons:
- There are probably more moons that we haven't discovered yet.
- It's not always clear whether something counts as a moon or not.
One way to give an exact number is to count the moons that have been given names by the International Astronomical Union. This includes most planet-orbiting objects more than a few hundred metres in diameter. As of 2020, there are 181 named moons in the Solar System.
However there are a couple of dozen more objects that we think are moons, but don't have names yet because we're still trying to confirm that they really are moons. These objects get temporary (provisional) names such as "S/2010 J 1" until they have been confirmed.
If we add up all the known and probable moons, we get at least 219.
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Author: Dave Owen