This stunning image, taken by the Hubble Space Telescope, shows the individual galaxies UGC 1810 (right) and UGC 1813 (left) in the process of colliding. Together, this pair of interacting galaxies is known as Arp 273. The interaction of galaxies is thought to be relatively common in the universe, particularly within galactic clusters, but the opportunity to directly observe one such as this is rare.
The two galaxies, with their nuclei separated by 100,000 light years, are located 300 million light years from Earth in the Andromeda constellation. A collision is actually thought to have already occurred, with UGC 1813 passing through the five times more massive UGC 1810. As a result, the smaller galaxy is now showing signs of intense star formation at its nucleus. It is possible, though, that they will collide again due to their gravitational attraction.
Most galactic collisions result in the merging of the two galaxies’ cores, but it’s unknown if that will happen in this case. What can be seen is a ‘bridge’ of sorts between the two where their spirals have been pulled apart by the other. It is thought that the interaction of Arp 273 may bear similarities to the eventual fate of our own galaxy when we collide with Andromeda in 4.5 billion years.
Image courtesy of NASA/ESA/HHT