So if you looked up sometime this week, perhaps at night, and you saw the "Blood Moon", thus:
you would probably, if asked, have said that you'd just seen "the Moon", or perhaps "the moon". If someone asked you what that big shiny thing in the sky which occasionally peeps out between the clouds in this country, you might say "the sun" or maybe "the Sun". That thing under your feet which separates the Kiwis from the Poms is frequently referred to as "the Earth", although probably more often called "the world", inaccurately of course because the world is everything and this planet is basically nothing compared to it. It's a bit like singling out a speck of dust you see in a beam of sunlight one morning and calling it "the Universe", except that that is a vast understatement considering how big the Universe is. Someone else has said something like this before, I know, and better.
So, there's this:
First of all, "the Moon", is just one moon, and in fact it might not even be that because it's suspiciously large. There are plenty of other moons going round other planets, like Io, Europa, Ganymede and Callisto, all of which orbit Jupiter. Calling the Moon that without having an alternative is a bit like being able to call "the Earth" "the Planet", which is fine on occasion, or even quite often, but without an alternative name, which is not fine at all. The Moon needs a name that's more than just a description of what it is. The reason I think this is that although of course the Moon is special, because its our moon, it's special in the same way as everyone is special, and that doesn't mean we go around calling everyone "The Person", and people would think it was odd if we did (and it would be confusing). My issue with this is that we need to remember that we live in an enormous Universe and that the Earth and the Moon are precious, rare, limited things which we should cherish, and we can do that by giving the Moon a name, which underlines that it's one moon among many. Therefore I call the Moon Cynthia.
Why Cynthia? Because it's one of Cynthia's traditional names given it by the Ancient Greeks and our culture is substantially Greek, which is why, for instance, we call Uranus that. There are various other options, such as Diana, Selene and Artemis, and I could've decided to choose those, but Artemis is ambiguous and a bit obscure, Selene is confusing to pronounce, and Diana is just a bit bland (and Roman). Also, it means we can say stuff like "Neil Armstrong's popped over to see Cynthia" or "don't you think Cynthia's looking nice tonight?" and so on, which I like, and for me Diana hasn't the same ring. I have no idea why it hasn't, but that's how it is for me.
Then there's "the Earth" versus "Earth". Again, Earth is special and in fact might be the only planet in the Universe with life on it for all most of us know, no matter how preposterous that suggestion is, but again I don't refer to myself as "the Amanda". The word "Earth" can be used generically like "moon", to refer to planets which are about the same size and temperature as this one, but "the"? Referring to it simply as "Earth" stresses that it's one planet among many, and in a way that makes it even more special and also makes the word "Earth" a proper name like "Cynthia" or "Vicky". It could be called Gaia and sometimes is, and that makes it seem like a living being, which it is. There are many living beings which are mainly dead, such as trees, so the fact that the living bit of Gaia is just a thin film on the surface of a ball of rock doesn't matter.
Finally there's the Sun. Again, the Sun is just a star with planets going round it, and like the other two it doesn't need the definite article. We could call it "Sol", but most stars have names like Alpha Centauri or HDE226868. From the Tau Ceti system, which is fairly nearby, Sol is just a star in the sky, and as it happens the cosmologist Carl Sagan made up a constellation for it to be in - the six-legged unicorn. Therefore, I would like to call "the Sun" Delta Sextupedalis, because it's a sextupedal unicorn and some constellations, such as Piscis Volans, the Flying Fish, are usually just called by the adjectival bit. I say "delta" because I'm estimating it would be the fourth brightest star in that constellation, as a star of its brightness from that distance in Gaia's sky is most likely to be the fourth brightest star in its constellation.
Cynthia is that thing in the sky with the rabbit on it.
Gaia is where we live.
Delta Sextupedalis is the yellow dwarf star we orbit.