Imagine ghosts made of light, crowding around a black hole the way birds crowd around water. They bark, flit and stab at the darkness with their beaks. The poem turns something cosmic and terrifying into a wild, almost animal scene of feeding.
The middle stanzas show the cost and the reward. The ghosts get pulled in, then break free, even shattering the "brittle edges of gravity" and eating the pieces. After they digest the darkness, they come out changed: their eyes shine through the hole, "black radiance" pours out, and dimensions get "rebooted." The final lines suggest a transformation. Insubstantial ghosts gather flesh and become "solid radiance."
The speaker doesn't seem afraid. The tone is fierce, playful and triumphant, with a strange sense of wonder. Judging by the imagery, the poem is about taking in what threatens you and turning it into strength. The mood is energetic and a little eerie, ending on a note of becoming real.