The James Webb telescope spotted “red dots” in the early Universe — dense objects tens of light-years across. Spectroscopic analysis of their light revealed the hue of hydrogen. Yet in X-rays they are nearly invisible, like a powerful spotlight wrapped in layers of gas curtains. The density of this curtain is staggering: more hydrogen falls into a tiny volume than exists in an entire small galaxy.
The answer lies in “light” dark matter, whose particles behave like waves over vast distances. They form stable clumps — gravitational funnels that draw in gas. As matter cools, it thickens the curtain around the center, hiding X-ray emission. Computer simulations confirm that when such funnels merge, structures identical to “red dots” emerge.
Now Webb lets us not only peer into the turbulent past of galaxies but also edge closer to solving the dark matter riddle.
To create such a curtain, more hydrogen falls into this tiny volume than exists in an entire small galaxy: this region is about the distance from the Sun to the nearest stars.
If light dark matter is real, space is permeated by a wave-like fog that shapes galaxy growth — an idea Ken Liu toyed with in his story “Waves,” where the structure of the Universe hinges on quantum fluctuations.