Or when to use capitals. Earth has a capital 'E'.
It certainly does when used as a proper noun or at the beginning of a sentence.
The very next time I use it in either fashion, I'll keep that in mind.
Curiously, the word 'satsuma' is much the same, referring to several places by that name, a couple different types of fruit, a genus of land snail, a type of pottery, and a few other uses.
I've never seen it
not capitalized. Oh, wait, strike that.
Aren't we talking about market capitalization here, and not word capitalization?