Pluto is a Planet asks:

In light of the discovery of 20 new moons around Saturn, I’d like to know what is your favourite moon in the solar system and why?

Do people have favourite moons?  Is that a thing?

Actually (and this is true, I posted about it on Facebook), my immediate reaction to learning about the extra twenty moons was “well, that’s just showing off.”  You only need one, don’t you?  What is a moon even for?  It does the tides, it gives you something nice to look at during the night, and it helps you keep track of the months of the year.  I mean, think, for goodness’ sake, how complicated the calendar would be on Jupiter. How complicated horoscopes must be.  Seventy-nine moons, not one of which can give you a neat twelve-month year.  There is something to be said for Kiviuq, one of the moons of Saturn, which can give you a very nice twenty-four-month year of about a thousand Saturnian solar days (about 450 Earth days) per month.  The only problem with that is that Kiviuq is about the size of Malta and basically indistinguishable from dozens of other lumps of rock orbiting Saturn that insist on being called “moons.”  And that’s another thing, Saturn – you haven’t got “eighty-two moons,” you’ve got seven moons and seventy-something pet rocks; you’re the planetary equivalent of a crazy cat lady (and, frankly, I’m being generous by counting Mimas, but I’ll give that to you because it looks like a Death Star).  Mars we have to forgive because it hasn’t got a proper moon, but when you pull this kind of $#!t, Saturn, it’s embarrassing.

Anyway, I guess the answer to this question really depends on what you want out of a moon. Like, Europa, Titan and Enceladus are arguably the most useful because they’re the most likely to be able to support life, and Enceladus is also by some definitions the brightest moon in the solar system, but Io is made of volcanoes, which is fµ¢£ing metal, and Triton has ice volcanoes, which doesn’t even make sense. Callisto is definitely the prettiest one, Rhea might have its own rings, which is cute in a “look, I’m just like dad!” sort of way, and… well, Miranda is just super fµ¢£ed up, so if nothing else you kinda have to admire its confidence. Ariel, Oberon and Titania are “meh” at best, although I will admit that Umbriel has a nice sort of dark-and-mysterious quality. Iapetus has the whole “yin-yang” thing, which is gimmicky but okay. Ganymede is coasting on its size and should try harder. Our moon is… fine. It is a classic moon, acceptable-to-good in all relevant parameters. It is not seriously in the running for Best Moon. Phobos is a potato and Deimos is a fµ¢£ed-up potato, and while potatoes are fantastic, a potato is not a fµ¢£ing moon. Charon… well, look, I know how you feel about this because it’s in the name you used, but Charon and Pluto are, like, co-moons, if anything. They’re doing their own thing. They’re fine. They don’t need our judgement. I can respect that.

This has been my objective, fact-based and unquestionable rating of moons. You are welcome.