+0
Hi,

I came across a few posts where the people commenting (or providing responses) on them told inquirers that proper nouns are nouns that have "the" in front and of things like "the earth", "the moon" and so on. Can you explain in detail about this, give me a previous post, or recommend a website?
Comments  
The presence of "the" does not create a proper noun.
Sometimes, not always, writers capitalize "earth", "sun", and similar terms which have unique referents, as in "the Earth", "the Sun". I do not believe that they are truly the names of those entities, and therefore I do not believe they are proper nouns. If they were, we could write "I see it's going to be a fine day because Sun is out", which is completely ungrammatical. "Sun" is not the name of the sun in the way that "Jim" is my name.
Personally, I do not use them in capitalized form. I find that these terms are left uncapitalized in most writings that I read here in the U.S.

CJ
Hello. "Sun" is the name we gave to a star. Therefore I believe that "Sun" is a proper noun.
Site Hint: Check out our list of pronunciation videos.
is earth a common noun or proper noun
Hello
i think that earth is a proper noun because it is just one.
is sun common or proper?
Students: We have free audio pronunciation exercises.
Didn't you read the thread?
Sometimes, not always, writers capitalize "earth", "sun", and similar terms which have unique referents, as in "the Earth", "the Sun". I do not believe that they are truly the names of those entities, and therefore I do not believe they are proper nouns. If they were, we could write "I see it's going to be a fine day because Sun is out", which is completely ungrammatical. "Sun" is not the name of the sun in the way that "Jim" is my name.

It depends. If you are referring to the earth as in the soil or ground, it is common. If you are referring to it as the planet, then it is proper, so you would capitalize it.