Scientists have been intrigued by the mysterious, ghostly circles circulating in deep space for years. They were first discovered in 2019, and now a new analysis has explained what these giant blobs are. The study, published in Nature, said these faintly glowing circles are actually shockwaves carved by tremendous winds blowing out from galaxies at their centres. But these galaxies are those that have undergone or are going through starbusting - a period of intense star formation - according to Science Alert.
In such galaxies, stars are born and die in rapid succession, ending their lives in spectacular supernovae.
"These galaxies are really interesting. They occur when two big galaxies collide. The merger pushes all the gas into a very small region, which causes an intense burst of star formation. Massive stars burn out quickly and when they die, they expel their gas as outflowing winds," astrophysicist Alison Coil of the University of California San Diego, who led the research, is quoted as saying by the outlet.
The new analysis suggests that this gas is pushed outwards (from the centre) and is caught up in the galactic winds. This phenomenon creates powerful shockwaves in the form of Odd Radio Circles, or ORCs.
They look like supernovae remnants, but scientists were stunned to find a galaxy in the centre of each ORC.
For the study, the team of astrophysicist Coil used the WM Keck Observatory to obtain optical data on one of the ORCs. They found that one of the ORCs had stars that are around 6 billion years old. This suggests that the galaxy underwent a burst of star formation, ending about a billion years ago.
The data crunching was done by highly efficient computers to determine if this starbusting could have produced an expanding bubble around the galaxy.
The computer simulation showed that a galactic wind of around 450 kilometres per second would emerge from a galaxy 200 million years ago, spurred by a high rate of supernova explosion. While the wind would die down, the hot gas would continue to travel outwards in a bubble.
The study said that the ORCs are produced by galactic outflows, possibly following a period of intense starburst.
