Answer:
The fact that Urania is a muse in Matthew Arnold's poem "Urania" emphasizes the idea that poetry and art are inspired by divine forces. The poem describes Urania as a source of inspiration and guidance for the speaker, who is seeking to understand the mysteries of the universe. By invoking the muse, Arnold is drawing on a long tradition of poets who believed that their work was not solely their own, but was instead a product of divine inspiration. The muse also serves as a symbol of the power of the imagination, which can transcend the limitations of the physical world and allow us to glimpse the eternal truths that lie beyond. Overall, the fact that Urania is a muse helps to underscore the central themes of the poem, which are concerned with the transcendent power of art and the human quest for knowledge and understanding.