“All enterprises that are entered into with indiscreet zeal may be pursued with great vigor at first, but are sure to collapse in the end.” -Tacitus
Dark matter makes up the overwhelming majority of mass in the Universe. With five times as much of it as there is normal matter, and the fact that it doesn’t emit or absorb light but does interact gravitationally, it might seem like the perfect candidate to form black holes. After all, it’s named “dark matter” to begin with, and black holes are perhaps the darkest form of matter in the whole Universe.
But black holes are also extremely collapsed objects, while dark matter is incredibly diffuse. The physics of what enables an object to collapse isn’t governed by gravity, but rather by the other forces: the ones that enable energy transfer, momentum loss and inelastic collisions. As far as we can tell, those are properties that are unique to the particles of the Standard Model, and dark matter’s inability to interact in those lossy fashions means it cannot collapse.