Imagine a spotlight: if you look at it from the side, it glows dim red, but if you stare straight into it, it blinds you with white-blue light. That, according to new data, is exactly what the mysterious 'little red dots' in the early universe look like. They are giant black holes, objects with gravity so strong that even light cannot escape, turned edge-on to us. They are surrounded by a thick disk of hot gas that hides the brightest radiation, letting through only a soft reddish glow and the characteristic emission of hydrogen — the same red as in neon signs.

Astronomers used to argue: maybe these are dense clusters of stars or unusually bright active centers of galaxies, where supermassive black holes devour matter. But the key clue came from spectroscopy — a method that splits light into colors and produces a 'color fingerprint'. The analysis of the spectra showed that the emission lines are stretched due to the expansion of the universe, which increases the wavelength of light from distant objects. This spectral 'signature' turned out to be familiar: exactly the same is seen in a stellar pair in our galaxy, the Milky Way, where a black hole pulls matter from a companion star, forming a hot accretion disk around itself. The spotlight analogy is apt: in such a system, if the disk is oriented edge-on, it blocks the brightest central radiation, and we see only the scattered reddish light from its outer regions.