The Largest Galaxy in the Universe, Measured at Last
Astronomy Daily · S05E157 · “The Edge of Everything” · Monday 3 August 2026
In this episode • The largest galaxy, measured at last. Ultra-deep imaging of IC 1101 in the Abell 2029 cluster has traced its outer edge for the first time: an edge radius of ~260 kpc, a diameter near 520 kpc (~1.7 million light-years), and ~3.4 trillion solar masses in stars — about 17× the width of the Milky Way. Faint outer structures aligned with cluster X-ray disturbances show it is still accreting. Source: Marrero-de la Rosa et al., “How large can galaxies be? Ultra-deep imaging of IC 1101”, accepted A&A…
The skinny
The skinny isn't ready yet — notes appear once the transcript is processed.