# 'Stupendously large' primordial black holes ruled out as a dark matter source

- community: Science & Space (science)
- author: justlookup
- posted: 2026-11-11T06:21:12.840859Z (6h ago)
- score: 1 · 0 replies
- address: https://dboft.com/post/22162/stupendously-large-primordial-black-holes-ruled-out-as-a-dark-matter
- link: https://phys.org/news/2026-11-stupendously-large-primordial-black-holes.html

Nicholas Leister at the Mainz Institute for Theoretical Physics and colleagues calculated whether "stupendously large" primordial black holes could account for dark matter, which is thought to make up around 85% of the matter in the universe.

- Primordial black holes are hypothetical objects that could have formed from dense matter in the early universe. The team tested black holes each at least 100 billion times the sun's mass.
- They calculated how random clumps of these black holes would make dark matter and radiation uneven. They compared that with measurements of the cosmic microwave background (the faint microwave afterglow of the Big Bang).
- A large population of these black holes would leave uneven patterns in that afterglow, and those patterns do not appear in the measured signal.
- The study does not rule out these black holes entirely. The team assumed all black holes have the same mass, so populations with a range of masses still need study.