Here's why:
* Nouns are words that name people, places, things, or ideas. For example: *cat, city, table, happiness*.
* Adverbs modify verbs, adjectives, or other adverbs. They describe how, when, where, or to what extent something happens. For example, *quickly, happily, beautifully, very*.
"Majestically" describes how something happens (with majesty).