Magnetic fields of the early universe created black holes ⚡ экспресс
For primordial black holes to make up a significant chunk of dark matter, a special spike in curvature (inhomogeneities) on small scales is needed. The authors propose a new mechanism: after inflation, during an era of stiff expansion (kination), vector perturbations from primordial magnetic fields act like a constant driver, generating second-order scalar perturbations. It's like an echo that doesn't fade but instead amplifies the sound. As a result, the curvature spectrum grows as k^{-5}, and black holes from this mechanism could very well be what dark matter is made of.
Shortly after the Big Bang, magnetic fields acted like a spoon, stirring spacetime and creating eddies. These eddies turned into clumps that collapsed into black holes — primordial, born without stars. Stephen Hawking and others considered them a possible explanation for dark matter. New work shows that such holes could have arisen due to magnetic fields during the era of rapid expansion. The eddies accumulated energy until they collapsed in on themselves. Their total mass is comparable to all dark matter. And one such hole could weigh as much as a mountain but be the size of an atom — if it passed through a planet, no one would notice.
🎯 A primordial black hole can weigh as much as a mountain but be the size of an atom.