Odd

Astronomers have discovered four rings, called “odd radio circles,” or ORCs, that so far have defied explanation or description. We don’t know how big the objects are, how far away they are, or how they formed-all we know is that they are only visible at radio wavelengths, where they are very bright at the edges. The ORCs are totally invisible when viewed with the visible, infrared, and X-ray wavelengths of the electromagnetic spectrum.

The paper describing this phenomenon, which was submitted for publication to the journal Nature Astronomy, offers explanations for ORCs but also methodically rules them out. So far, supernovas, star-forming galaxies, planetary nebulas, and gravitational lensing have all been excluded as possible explanations.

Two of the ORCs appear to contain central galaxies that can be seen at visible wavelengths; scientists speculate those rings could be connected to some kind of local galactic phenomena. The other two ORCs share close physical proximity and so could be interconnected in some way.

Astronomer Kristine Spekkens at the Royal Military College of Canada and Queen’s University says,

“[The objects] may well point to a new phenomenon that we haven’t really probed yet. It may also be that these are an extension of a previously known class of objects that we haven’t been able to explore.”