You’ll be prosperous if you find phosphorous phosphorus in the Bosporus.

The title is a typo. "Phosphorous" is an adjective. The correct noun is "phosphorus." The linked article uses it correctly, so only OP screwed up here.

The title of the post (on Hackernews, above) has the spelling "Phosphorous" (with a U). This is the spelling of the Adjective (a describing word). It is a mistake in this context, because what has been discovered in the outskirts of the Milky Way is not a grammatical construct but rather a chemical element.

The chemical element is spelled without the U (even in British English!): Phosphorus.

https://grammarist.com/spelling/phosphorous-phosphorus/