Hubble's Blank-Sky Gamble Unveils a Cosmic Forest of Galaxies

In 1995, the Hubble Space Telescope stared for ten days at a deliberately empty patch of sky in Ursa Major, assembling 342 exposures and over 100 hours of data to produce the Deep Field image. Despite initial resistance and Hubble’s repair history, the image revealed roughly 3,000 faint, distant galaxies, supporting a picture of galaxy formation through mergers and growth. The data were released openly, catalyzing a standard approach and leading to even deeper fields with Hubble and, later, the James Webb Space Telescope.