As much as astronomy has revealed to us about the universe, there is still much we don’t know and anomalous discoveries routinely remind scientists of this. The newest discovery could be a totally brand-new type of astronomical object that is fascinating and a bit spooky.
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.”
Other astronomers have speculated the ring-shaped islands in deep space could be the result of shockwaves or radio galaxies.
Astronomers discovered the ORCs while working on another project, the Evolutionary Map of the Universe (EMU), which is a map of radio frequencies in space. The EMU pilot survey employs the Australian Square Kilometer Array Pathfinder, or ASKAP, a radio telescope network of 36 dish antennas which are collectively generating a wide-angle view of the night sky and which scientists expect will identify 70 million new radio objects.
“This is a really nice indication of the shape of things to come in radio astronomy in the next couple of years,” Spekkens added. “History shows us that when we open up a new [avenue of looking at] space to explore … we always find new and exciting things.”
The discovery comes right at a time when astronomers are still struggling to understand more about another space radio anomaly, the Fast Radio Bursts, or FRBs, that spew incomprehensible amounts of energy in concentrated beams across the universe. While there are many outlandish speculations–including often specious murmurs of advanced extraterrestrial life–anytime scientists discover something in space that defies explanation, we will have to wait substantially longer to learn what both ORCs and FRBs really are.