Within the Matoran Universe, stars are said to be projections of the brain patterns of Mata Nui. That explains why there are stars in Metru Nui, the robot’s “brain”. But why would there be stars over other islands? I’m assuming there are, but I can’t remember any specific reference to stars over other lands, so I’m also asking that, too, to be sure.
(This question doesn’t concern Mata Nui, Voya Nui, or any other place with a tual cosmic stars, of course.)