An article published in “The Astrophysical Journal Letters” reports the discovery of what was dubbed Cloud-9, which can be described as a failed galaxy. A team of astronomers used observations with the FAST radio telescope to identify what appears to be a new type of astronomical object, and follow-up observations with the Hubble Space Telescope, the Green Bank Telescope (GBT), and the Very Large Array (VLA) to confirm the existence of the first object of its kind that was identified with reasonable certainty.

Technically defined as a reionization-limited H i cloud (RELHIC), Cloud-9 is a starless gas cloud that is supposed to be composed of dark matter filled with hydrostatic gas in thermal equilibrium with the cosmic ultraviolet background. Cloud-9 will help test cosmological models regarding dark matter.