Odd_radio_circle
Odd radio circle
Unexplained circular astronomical object detected only by radio waves
In astronomy, an odd radio circle (ORC) is a very large (over 50 thousand times the diameter of our Milky Way ~ 3 Million Light-years) unexplained astronomical object that, at radio wavelengths, is highly circular and brighter along its edges. [3] As of 27 April 2021, there have been five such objects (and possibly six more) observed.[4][5][6][7][8][9][10] The observed ORCs are bright at radio wavelengths, but are not visible at visible, infrared or X-ray wavelengths. This is due to the physical process producing this radiation, which is thought to be synchrotron radiation.[4][5] Three of the ORCs contain optical galaxies in their centers, suggesting that the galaxies might have formed these objects.[5][10]