No, past does not have to start with a capital letter.
Earth, as in we live on the planet Earth, is supposed to be capitalized. Earth, as in the dirt we walk on, is not supposed to be capitalized.
Usually, yes a phase of the moon is supposed to be capitalized.
No, it shouldn't be capitalized.
No it shouldn't be capitalized.
Yes, America should be capitalized.
no
Yes, "Pterodactyl" is supposed to be capitalized as it is a proper noun referring to a specific genus of pterosaur.
No, the word 'capitalized' is the past tense, past participle of the verb 'to capitalize'. The past participle of the verb is also an adjective; capitalized words, capitalized financing.
No, but the names of individual languages are capitalized.
Yes, Siamese would be capitalized.
No it shouldn't be capitalized.
Yes.