The James Webb Space Telescope has spotted a scattering of compact objects in the early universe, nicknamed 'little red dots.' They are too red and too dim to be ordinary quasars, and astrophysicists are scratching their heads over what powers them. Stephen Adler offers an unexpected answer: they are not black holes but gravastars, compact objects without an event horizon, born from a phase transition in matter.

The metaphor here is a well without a bottom but with walls. Inside a gravastar, pressure reaches a critical value, and matter abruptly transitions to a state with negative energy density. The released latent heat is the source of light. But the light is born so deep in the potential well that it emerges heavily reddened: gravitational redshift stretches its wavelength by a factor of billions. There is no horizon; g00 remains positive but exponentially small, so the object looks like a nearly perfect black body.

Previously, it was unclear what powered the 'little red dots,' why their luminosity barely changes, and how to avoid the horizon and the information paradox in compact objects. Now it is clear that both puzzles can be solved by a single mechanism: the phase transition provides both a horizonless object and an energy source, plus a natural explanation for the redness. The model is built on exact solutions of the Tolman–Oppenheimer–Volkoff equations with a phase transition, and the sequence of equilibrium states under slow accretion has been traced.

The prospect is exciting. If the hypothesis holds, supermassive black holes at the centers of galaxies might actually be horizonless gravastars, which would resolve the information paradox and reshape models of galaxy formation. The next step is to look for correlations between the radii and masses of the red dots and to try to distinguish gravitational redshift from absorption via spectral shape or polarization. A well without a bottom but with walls could be the key to the darkest corners of the universe.