Adrienne Rich's "Planetarium" is a feminist poem whose unconventional structure and line organization reflects its thematic contents which discuss subversive women and their non-traditional lives. Writing in free verse, Rich uses the fabric of Caroline Herschel’s life story to support a broader discussion of women’s work and the pressure of social expectations that so often restrict female expression. 

Beginning with a traditional author’s note written in brief italics, Rich explains that the poem was produced while thinking of the German-born astronomer Caroline Hersch. “Thinking of” Hersch’s story, Rich was struck by her predecessor’s life and its similarities to the poet’s own. In the poem, the astronomer’s career and its historical retelling become a metaphor for all women working to supplant convention and forge paths for themselves. Indeed, it is a narrative with which Rich herself, a female poet grappling with her femininity at the edges of the still-heavily masculine literary world, must have identified heavily. 

Beyond the author’s note, nothing in the poem is regular or conventional. The poem is itself a “monster” living on the outskirts of poetry, neither familiar nor palatable to close-minded contemporaries. It does not reflect what a poem is expected to be any more than a woman, such as Herschel, who works "among the Clocks and instruments" reflects what society expects a woman to be. The chiastic structure, which reverses the comparison of “monster” and “woman” in the opening two lines, forces the reader to recognize that, in Rich's view, these two groups are often equivalent concepts. Women who fall outside of the scope of expectation are, to many, no longer women. They are viewed as other or alien and are little more than monsters housed in a deceptive female facade. 

A semantic field of stars, cosmic bodies, and scientific tools lends the poem a sense of thematic cohesion, united by the “moon” and “galaxies” blazing overhead and the “polished lenses” and “instruments” by which they are viewed. Structurally, the poem begins to break apart at the emergence of the nova. As Tycho Brahe, the speaker and the reader both encounter “the / NOVA,” a catalytic moment that mirrors women’s interactions with the world around them. These collisions of woman and society, like a nova, cause an explosion, and push the "life...out of" creative and inspired women even as they strive not to have "lived in vain." After the encounter with the nova, the poem returns to something that almost resembles a regular poetic format: groups of two lines reflecting the vain attempts of women to conform. Ultimately, however, women are "bombarded,” kept in check by an onslaught of expectation and demanding convention. “Yet,” the speaker writes, as she adds physical space between the contents of the line, “I stand.” 

The final section of the poem is a visual representation of this stand. A solid block of text, the final stanza refutes accepted grammatical structures, rejects punctuation, and includes spaces where they would not be expected. Here, rejection of the norm makes the speaker strong. She is standing in the path of a "battery of signals" directed at her by the world around her. As such, she intends to turn herself into an "instrument" capable of deciphering these "untranslatable" ideas. As the poem suggests, the signals are sometimes so multitudinous and so confusing that it is all a woman can do to stand up to them and let them ebb through her, questing all the time for a "relief" the world does not want her to feel.