The James Webb Space Telescope has spotted tiny, unnaturally bright red objects in the early universe. Their light outshines by a hundredfold what you’d expect from ordinary galaxies of that era. Inside, they likely hide black holes with the mass of billions of suns — except there wouldn’t be enough time for them to grow gradually since the Big Bang.
A new study offers a solution: these black holes didn’t grow: they were born giants. They emerged from dark matter — the invisible stuff that permeates the cosmos. In the early universe, a phase transition occurred, much like a pot of cooling jelly: almost all the matter instantly solidified, but here and there liquid pockets remained. These rare bubbles collapsed under their own gravity, forming supermassive black holes without the need for slow growth.
The same process would have generated gravitational waves, ripples in spacetime, of ultra-low frequency. Each such wave is longer than our entire galaxy and squeezes and stretches the Earth by a fraction of a proton. We could detect them by watching pulsars: these dead stars spin with the precision of atomic clocks, and the slightest hiccup in their rhythm would betray a passing gravitational wave. If the signal is found, the hypothesis gets undeniable proof.
According to the authors’ calculations, the primordial black holes in the red dots could reach ten billion solar masses — almost as much as the entire Milky Way galaxy!