I recently attended a talk where the speaker said that it is impossible for us gain information about the history of particles which make up the black hole. i.e we won't know if the black hole was formed due to huge lump of hydrogen or if it was due diamonds. I not quite sure about how will it conceal the information about the charge of particle. Can you explain?
But my main question is that- Is the above principle(?!) applicable only to standard model particles or is it a general one for all particles interacting through gravity?
Will Dark Matter follow it? If no, Can we somehow distinguish it form the rest?