Late at night, the speaker is thinking about someone who is no longer there. The poem never says exactly what happened, but the closing words, "lay to rest," and the line "when you went" suggest the person has died, though it could also be read as a loss of another kind.
Each stanza starts with something in the night: the stars, the moon, the silence. Each one sends the speaker back to the other person's eyes. First those eyes held a galaxy, then they were big and full of love. The images are gentle and almost awestruck, as if the speaker remembers this person as something vast and glowing.
The last stanza changes the tone. The stars and moon gave comfort, but the silence is "deafening," and it is all that remains. The mood is quiet, tender, and aching. The poem moves from warm memory to an empty room, and the plain, lowercase voice makes the grief feel private and honest.