Twenty words, one sentence, no line breaks. "Phases" is so small that it's tempting to read it in a glance and move on. Slow down, though, and it turns out to be a tiny drama: a woman opens her eyes in the dark and finds that the dark is not empty.
Start with the title. "Phases" is plural, yet the poem shows only one moment. The moon has phases, of course, and so do people, so the title invites us to read this scene as one stage in a cycle rather than a final verdict. The poem backs this up in its first phrase. "An instant of darkness" fuses a unit of time with a condition of light, so the dark becomes something that happens briefly, like a blink or a lapse, rather than a place she lives in. Whether this is ordinary night, a sudden waking, or something closer to a low point in a life, the poem never says. That openness seems deliberate, and it lets readers bring their own darkness to it.
The grammar tells its own small story. At first "she" is the subject, and the only thing she does is open her eyes, a modest, almost involuntary act. Then the sentence hands the action over to the moon, which becomes the subject of "smiled." She ends up as the object, and the very last word is "her." The sentence moves from a person who sees to a person who is seen, and the whole thing seems to be travelling toward that moment of being noticed.
The poem has no rhyme scheme and no regular metre. It reads like a line of prose, but its sounds are carefully shaped. The commas set "radiant in the gloom" off as an aside, so the light seems to hover in the middle of the sentence, hemmed in by dark words: "darkness" at the start, "gloom" inside the phrase itself. The darkness doesn't disappear when the moon arrives. The moon is "radiant in the gloom," not instead of it, and the brightness depends on the dark around it. "Moon" and "gloom" also share a long, hollow "oo" sound, a near-rhyme that ties the light to the thing it contrasts with. Soft consonants (the m's and l's of "smiled," "moon," "gloom") give the whole line a hushed quality. Then the final four words, "smiled down on her," are all single syllables, and the sentence slows and settles, like someone lying back.
The central image is personification: a smiling moon. That's an old and familiar idea, but the poem gives it a direction with "down." The moon looks down on her the way an adult leans over a bed, so the gaze reads as protective rather than superior. There is also a quiet link back to the title. A crescent moon really does look like a smile, so "phases" and "smiled" may be pulling in the same direction, although "radiant" suggests a brighter, fuller moon, and the poem leaves the exact phase for us to decide.
What the moon offers is company, not rescue. It doesn't banish the gloom or fix whatever the darkness stands for. It simply looks at her kindly, and the poem suggests that this is enough to change the character of the moment. The darkness is "an instant," while the radiance and the smile have the last word.
That is where the poem's interest lies. It shows how much a single sentence can carry when its structure does emotional work: the shift from subject to object, the dark framing the light, the slowing rhythm of the close. It also leaves gaps on purpose. We never learn who she is or why the dark came, so we have to fill those in ourselves. A poem this short asks the reader to do half the work, and here that feels like part of the point.