Because it's not universally agreed upon, that's why old mate.
That "black" is quite cool and the planets rising simulation excellent!
Reminds me of the movie Father of the Bride.
The father thought he had a "black suit". The wedding planner (Franck, pronounced "Frunk" played by Martin Short with a shocking god knows where from accent) is trying to repair George Banks' tuxedo (played by Steve Martin):
Franck Eggelhoffer: Uh-oh, I bring the wrong color thread. I assumed you'd be wearing a black "tuxado."
George: It is a black "tuxado."
Franck Eggelhoffer: I don't think so, babe. This tux is "nuffy" blue. No doubt about it.
George: What're you talking about? Armani doesn't make a blue tuxedo.
Franck Eggelhoffer: Armani don't also make "polyaster."