Competition thrives through all of "Dangerous Astronomy". It's as if there are several forces competing all at once through the speaker's perspective. These forces—his desire to praise the stars, his son's comfort, his wife's love—all collide in the bedroom, and luckily for us, the speaker walks us through the gritty details of what it felt like not to come out on top.
The speaker of "Dangerous Astronomy" finds himself competing with his baby son, his wife, and ultimately God, until the end of the poem, when he realizes his competitive nature is the problem in the first place. It gets in the way of his ability to love.
"Dangerous Astronomy" details a power struggle within the speaker's family, and it's through this struggle that the speaker awakens to a deeper understanding of how to be a good father and husband.