Astronomers finally measure the full size of the largest known galaxy

Researchers have obtained the deepest images ever taken of IC 1101, allowing them to identify the galaxy’s outer edge for the first time. The observations confirm it as the largest known galaxy, spanning roughly 520 kiloparsecs, or about 1.7 million light-years, and containing an estimated 3.4 trillion solar masses in stars. The paper was posted to the arXiv preprint server on July 16.