23:00 16 July 2009
The universe's galaxies are the nurseries of stars, and in one known case life, and come in an impressive range of shapes and sizes. But only recently has it become possible to simulate how that diversity came about.
Explore the images below to discover the different kinds of galaxy in the universe, and read our feature to learn how astronomers are starting to build their own virtual galaxies using complex simulations.
Image 10 of 11
NGC 1427A. Irregular galaxy
Most galaxies are either spirals or ellipticals, but about 3 per cent are very different. These "irregular galaxies" share few common properties, but many get their unusual shapes from gravitational interactions with other galaxies.
NGC 1427A (large bluish smudge at centre) shows how gravity can deform a galaxy's shape. The arrow-shaped galaxy is being pulled towards the centre of a cluster of galaxies known as Fornax (upwards in this image) at 600 kilometres per second. Its movement through the cluster's gas compresses its own gas clouds, triggering star birth. But it will not survive the passage through the cluster – within a billion years, its shape will be completely scrambled, and its stars and gas will be subsumed into the gas inside the Fornax cluster. (Image: NASA/ESA/Hubble Heritage Team/STScI/AURA)