Galaxies are by no means static islets of stars - they are dynamic and constantly changing objects moving in the dark void of the universe. Occasionally, galaxies can experience violent collisions, as seen in this image of the Arp 256 system taken with the Hubble Space Telescope.
At a distance of 350 million light-years from us, a pair of barred spiral galaxies located in the direction of the constellation Cetus began to merge into a single galaxy. This image captures one single moment of merger, and shows gas, dust and stars being ejected from galaxies by the gravitational forces that merge.
Although the galactic nuclei are still separated by a fairly large distance, the shape of the Arp 256 galaxies is already significantly distorted. The galaxy at the top of the image shows pronounced tidal tails - long, extended ribbons of gas, dust and stars.
These galaxies sparkle with bright regions of active star formation: the bright blue "celestial fireworks" are "star factories" that produce hot young stars.
The Arp 256 source was first registered by Halton Arp in 1966 as one of the objects of his Atlas of Peculiar [unusual - approx. per.] galaxies ". The purpose of compiling this catalog was to classify examples of unusual and amazing structures among nearby galaxies, which reflect different stages in the evolution of galaxies. These peculiar galaxies reflect the transient processes occurring during the transformations of spiral and elliptical galaxies.
This image was taken with the Advanced Camera for Surveys (ACS) and Wide Field Camera 3 (WFC3) of the Hubble Space Telescope. The image is a new version of the previously published image in 2008, which was part of a collection of 59 images of merging galaxies, published for the 18th anniversary of Hubble.