Is the Earth a proper or common noun? [duplicate]

Solution 1:

The question is asking whether "earth" in “The earth moves [a]round the sun” is a common or proper noun. If the authors had capitalized it, then technically, the answer would have been "proper noun".

Proper nouns do not normally take a determiner. For example,

• Let's go to Paris on Thursday.
• I left Washington last night.
• Did you visit Lake Como in July?
• Her favourite movie is, When Harry Met Sally.

BUT there are exceptions

• Have you ever seen the Amazon River?
• I saw special gift subscriptions on The New York Times.

However, these proper nouns are always capitalised whereas earth is also a common noun and a synonym of soil, land, dirt, ground, terrain etc.