The first stage is nebula, right? Then, by condensation, nebula becomes star. There is thermonuclear fusion reaction there, right?
The first stage of fusion is two hydrogen atoms fused, become a helium atom. Helium atom is heavier than hydrogen atom. But a helium atom is slightly lighter than two hydrogen atom. There is a mass defect. So, is it true that nebula mass is greater than star' s?
Let us continue. Star evolves. Finally, it may becomes Black Hole. If star is lighter than nebula, is Black Hole is lighter than star :unsure: ?