Is it the definite article?

So, to reiterate, when it comes to when to use the “the”, the only universal rule is this:

Some rules (such as the two you’ve given) might hold 95%+ of the time, but unfortunately there may be weird and arbitrary exceptions that you’ll just have to learn.

Source: ell.stackexchange.com/questions/365074/…/365083#3…

Is it capitalization?

A cursory look at the Wikipedia page for capitalization also reveals that capitalization is not without its quirks.

For example:

planets and other celestial bodies: “Jupiter”, “the Crab Nebula”; and “the Earth”, “the Sun”, or “the Moon” should be capitalized according to the International Astronomical Union based on its manual of style, but style guides may suggest differently.[19]

Source: en.wikipedia.org/wiki/Capitalization_in_English

Please tell me your thoughts.