Black Holes may have a meaning in Concave Earth. Why not?
Stars are certainly not fantasy.
They are probably a wonderful big number of small cavitation/sonoluniscence phenomena in Celestial Ocean inside Firmament.
But, observation show that some stars in center of galaxies cease to exist (maybe just cavitation implosion more often in one point).
Others stars are created (and we don't know how and were the bubbles and the sound comes from)
Sun is defined wrongly in pseudoscience and it exists.
Moon is defined wrongly in pseudoscience and it exists.
Planets are defined wrongly in pseudoscience an they exists.
Stars are defined wrongly in pseudoscience and they exists.
Galaxies are defined completly wrongly in pseudoscience and they exist.
Some places in Celestial Sphere stars cease to exist (usualy in center galaxies) and pseudoscience call most of those places as Black Holes.
All Universe is inside Earth, and certainly too the places (black holes?) where stars (the real ones: billions of small cavitation/sonoluminiscence) bubbles cease to exist