Literally anything else. Earthpics, coolearthpics, globescope, naturerama, third planet...that was just 5 seconds of thinking. Using the word porn for everything just lacks creativity.
Is there something about the word "porn" that actually communicates "really pretty pictures of something but without any human creations" beyond its Reddit meme usage? Because it doesn't for most people.
Also, not all community rules and objectives need to be in the name and URL. The word "porn" in URLs is problematic for users sitting behind state or corporate internet connection though. Be kind to your local network administrators!
Porn in the sense of something that is the sort of over the top example of a thing that elicits an almost aroused response. Like a gratuitous picture of food would be considered FoodPorn. Or like 2 perfectly machined pieces of metal fitting together perfectly would be EngineeringPorn.