The Hubble Telescope spotted a rare collision that formed when a small galaxy hit the centre of spiral galaxy NGC 922, shooting out the other side, forming a ring structure 330 million years ago.
Galaxies merging and colliding is not uncommon, but this structure is because the galaxies had to hit at a precise spot and have a certain size ratio to create the ring form where a nebulae encircles the core, the scientists said.
A press release from spacetelescope.org explains:
As the small galaxy passed through the middle of NGC 922, it set up ripples that disrupted the clouds of gas, and triggered the formation of new stars whose radiation then lit up the remaining gas. The bright pink colour of the resulting nebulae is a characteristic sign of this process, and it is caused by excited hydrogen gas (the dominant element in interstellar gas clouds). This process of excitation and emission of light by gases is similar to that in neon signs.
[credit provider=”NASA, ESA” url=”http://www.spacetelescope.org/news/heic1218/”]