In the early Universe, just a few hundred million years after the Big Bang, special 'seeds' were born in dense gas clouds — supermassive black holes. Computer modeling showed that these embryos were ten times heavier than previously thought: each weighed a million Suns.
Around each seed, a gas disk spun rapidly. Falling onto the embryo, the gas heated up and began to shine brightly, especially in the red hydrogen line. The James Webb Space Telescope sees this glow as mysterious 'red dots' in distant galaxies. By studying this light, scientists, spreading it into a rainbow, notice that hydrogen lines are smeared — that's how fast the disk spins.
But the most unexpected: these baby black holes break the cosmic 'speed limit' of accretion. Normally, radiation from infalling matter pushes away new food, but here the gas spirals inward so rapidly that in 200 million years the seed turns into a monster with tens of millions of solar masses. This explains where those giant quasars came from that puzzled scientists. By that time, the universe had expanded (redshift z~8), and these 'red dots' had already grown into adult black holes.
A black hole seed is a billion times lighter than an adult giant, but it grows so fast that it gains almost all its mass in 200 million years — like an acorn turning into a century-old oak in a single day.