Imagine a black hole originally formed from, for example, Rubidium atoms. On the other hand, one made from, for example, Helium atoms. Will it be there any difference between the two? Or perhaps once formed it all turns into the same type of matter?
Can the "composition" of the matter-energy in the black hole be inferred somehow?
Could one say that "black hole substance" is a distinct form or state of matter different from other forms or states of matter?