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Name: Maxwell 
Status: student
Grade: 6-8
Country: USA
Date: Spring 2012

Does the mass of a planet effect how many moons it has?


Since moons (just like the star and the planets of a solar system) are the result of gas clouds that clump together to become more massive objects which then are attracted to other bodies with strong gravitational force, then in principle the more massive a planet is, the more moons it can attract. Everything else being equal there should be a relationship between the mass of a planet and the number of moons it has. However, if you look at the data table in this website: If you plot the number of moons as a function of the mass of the planet, you will see that while there is a positive relationship, it is not a linear relationship. This means that there are other factors controlling how many moons a particular planet manages to attract.

Greg (Roberto Gregorius) Canisius College

The very short answer is 'no'. Though the large planets, such as Jupiter, do have many moons, there is no 'law' that dictates that Pluto cannot have 10 or 12.

Howard Barnes Astronomer.

Dear Maxwell,

Good question. Not really, because little Pluto has 5 moons; Earth only one, Jupiter, the great biggest planet, has 64 known moon as of today (March 2012), but smaller Saturn has at least that many, and possibly as many as 200. Mars, which is far smaller than Earth, has two small moons.

Sincerely David H. Levy

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