This is one of the first philosophical poems in Russian professional literature called "Evening Meditation on God's Majesty on the Occasion of the Great Northern Lights". Where is the riddle here? Everything that Lomonosov lists is a confirmation of God's greatness, no riddles.
I don’t know what the answer to this question should be - heaven? An abyss full of stars is the sky. But here M.Yu. Lomonosov really wrote about his reflections on the structure of the world, on the riddles and wonders of all living things. You have taken a quote from Lomonosov's poem "Evening Meditation on God's Majesty on the Occasion of the Great Northern Lights." It's about the sky.