Mireia Montes

Astronomers used the infrared telescope and the old Hubble to discover a gaping void in the center of a galaxy in the Abell 402 cluster, as if an invisible tugboat had pulled billions of stars out of there. The missing mass equals two billion suns: it's not a cloud but a real lack of stars.

In galaxy clusters, invisible dark matter serves as the framework holding star systems together. Its shape is betrayed by a faint glow — stars ripped from galaxies by tidal forces. This stellar 'broth' fills the cluster like a liquid taking the shape of its container: it envelops the clumps of dark matter, creating a precise cast of their outlines.

The night sky only looks black: telescopes reveal millions of galaxies, but some are so dim they blend into the background. Astronomers caught just such a "nearly invisible" one by chance while observing the Virgo Cluster with the two-meter telescope at Teide Observatory. The galaxy is named TTT J1237327+143535.