Malin-1 (arrowed) is a most unusual galaxy, seen here as a negative image before and after photographic enhancement of plates from the UK Schmidt telescope. This insignificant smudge is the largest gas-rich galaxy known but is very inefficient at forming stars, so has a very low surface brightness. Its enormous but faint optical disk is six times bigger than that of the Milky Way, itself a major galaxy, and it contains enough hydrogen to make 100 billion stars like the Sun. It was discovered while searching for faint dwarf galaxies in the nearby Virgo cluster of galaxies. A normal spiral system belonging to the Virgo cluster is the bright object at lower centre. Malin-1 is at a redshift of 0.083, corresponding to a distance of about a billion light years, while the Virgo cluster is about 50 million light years distant.
Original plates taken with the UK Schmidt Telescope