Understand it first as not metaphorical. "Glow" is peripheral to "our prosperity," meaning developed areas. I think you're being confused by "our prosperity," an abstract term, being used to mean "places where humans live in high enough numbers to cause light pollution."

The writer is using "our prosperity" to indicate light pollution is a side effect of that prosperity, but the glow of light pollution is tangible and peripheral to developed areas.

All that said, though, there is a second metaphorical meaning which is complementary to the literal meaning, where "peripheral glow" can mean all spheres of influence where humans are having an effect.

I think it's a nice turn of phrase.

Understand it first as not metaphorical. "Glow" is peripheral to "our prosperity," meaning developed areas. I think you're being confused by "our prosperity," an abstract term, being used to mean "places where humans live in high enough numbers to cause light pollution."

The writer is using "our prosperity" to indicate light pollution is a side effect of that prosperity. The glow of light pollution is tangible and peripheral to developed areas. If you understand "our prosperity" as a location (cities), it's not metaphorical at all.

All that said, though, there is a second metaphorical meaning which is complementary to the literal meaning, where "peripheral glow" can mean all spheres of influence where humans are having an effect.

I think it's a nice turn of phrase.

"Secondary" doesn't work as the relationship being described between humans and nature is a spatial one, even in the metaphorical sense. I can understand why you might think it's a hierarchical one, as humans affect everything in some way, but in the arena of light pollution, you can escape humanity's sphere of influence.