Primordial black holes are hypothetical objects that could have formed directly from dense clumps of matter in the very early universe. If they exist, their dramatic origins would set them apart from the black holes we see today, which form when massive stars collapse. Some theories suggest that “stupendously large” primordial black holes could account for a significant share of the universe’s elusive dark matter.

Yet new calculations by Nicholas Leister at the Mainz Institute for Theoretical Physics and colleagues show that even if these immense objects do exist, they can’t make up any meaningful fraction of dark matter.

Their research has been published in Physical Review Letters.