# What particles are black holes made of?

## Main Question or Discussion Point

What particles that constitute the black holes?Does normal particles constitute the black holes?
How can we calculate the ratio of types of particles in the universe(we consider known matter but not consider dark energy and dark matter)?How can we calculate the total number of particles in the universe?

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DaveC426913
Gold Member
Black holes are not made of particles. A black hole is defined by a region of extremely curved space, caused by the presence of extremely dense mass. The type of mass that creates the curved space is irrelevant.

Then if we do not consider Black Holes,Dark Matter and Dark energy,could we calculate the ratio of types of particles? Could we calculate the total number of up and down quarks,of electrons and of neutrinos in the Universe?

PeterDonis
Mentor
2019 Award
could we calculate the ratio of types of particles? Could we calculate the total number of up and down quarks,of electrons and of neutrinos in the Universe?
We can make rough estimates for the number of atoms in the observable universe based on the total amount of mass; see, for example, here:

https://en.wikipedia.org/wiki/Observable_universe#Matter_content_.E2.80.94_number_of_atoms

This estimate is based on most of the atoms being hydrogen atoms, so the number will also give a rough estimate of the number of protons (and hence quarks) and electrons. You could use estimates of the relative abundance of heavier elements to make a rough estimate of the number of neutrons (which would adjust the estimate for quarks). I'm not sure how you would estimate the number of neutrinos, since they are too light to affect the total mass significantly.

Orodruin
Staff Emeritus