It seems somewhat hard to understand why are black holes being included in this list—for objects that by their definition cannot be observed directly, there certainly seems to be a whole lot of a solid observational evidence for their existence, both in the case of stellar and supermassive ones.
It seems somewhat hard to understand why are black holes being included in this list—for objects that by their definition cannot be observed directly, there certainly seems to be a whole lot of a solid observational evidence for their existence, both in the case of stellar and supermassive ones.
True. Higgs Boson anyone?