perpetually vs constantly

perpetually and constantly both are adverbs.

Word	Noun	Adjective	Verb	Adverb
perpetually	No	No	No	Yes
constantly	No	No	No	Yes

As adverbs, perpetually and constantly are synonyms defined as:

Other synonyms of perpetually include always, forever, incessantly.

perpetually (adverb)	constantly (adverb)
invariably	invariably
everlastingly; for all time	without variation or change, in every case