'Stupendously large' primordial black holes ruled out as a dark matter source
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…
A new study ruled out the possibility that stupendously large primordial black holes could make up a significant portion of the universe's dark matter. These hypothetical objects, weighing at least 100 billion times the mass of the Sun, were once considered as a potential dark matter candidate. However, the research by Nicholas Leister and colleagues at the Mainz Institute for Theoretical Physics, published in Physical Review Letters, found that even if such black holes exist, they could not account for a meaningful fraction of dark matter.
The authors suggest that the distribution of these black holes would create noticeable variations in the cosmic microwave background (CMB), the afterglow of the Big Bang. However, measurements of the CMB do not show these expected patterns, indicating that a large population of stupendously large primordial black holes is unlikely to be the main component of dark matter.
The study does not completely rule out the existence of primordial black holes of this mass range, as populations with a range of masses could still contribute to dark matter. Future CMB experiments like LiteBIRD and the Simons Observatory aim to further tighten these limits and search for gravitational waves that could provide additional insights into the formation of these massive black holes.
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