Read this statement by c. k. williams about walt whitman. for a young poet, reading whitman is sheer revelation, sheer wonder, a delight bordering on, then plunging into disbelief. how could all this have come to pass? . . these countless images of daily life, of common life made uncommon, and the most boldly uncommon made jarringly intimate? this is best reflected in “when i heard the learn’d astronomer,” when

This is best reflected in “When I Heard the Learn’d Astronomer,” when Whitman goes out at night and looks at the stars.
After a boring lecture during his class, he wanders out of the classroom and starts staring at the stars. This is when his most wondrous and clever thoughts emerge when the full impact of the era of Transcendentalism is obvious. The stars have such an effect on him and give him the inspiration to write this poem and marvel at them.

The answer would be logical.