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Explanation: What do you call a cosmic puzzle that no one expected to see? In this case, Odd Radio Circles, aka ORCs. ORC-1 typifies the enigmatic five objects, only visible at radio frequencies, that were serendipitously discovered in 2019 using the new Australian SKA Pathfinder radio array. The final image in the featured video uses 2021 data from the South African MeerKAT array to reveal more detail. The radio data, assigned turquoise colors, are combined with a Dark Energy Survey optical/IR map. The animated artist’s illustration explores just one idea about the ORCs’ origins. If two supermassive black holes merge...

Astronomers call it an odd radio circle or ORC. Astronomers have spotted only a handful of ORCs. They’re huge, about a million light-years across (16 times bigger than our Milky Way galaxy). Despite this, the ORCs are hard to see. They’re visible only at radio wavelengths. And, so far, they are unexplained. Since their discovery in 2019, astronomers have proposed different explanations for them, including galactic shockwaves, or the throats of wormholes. What are they? Ray Norris from Western Sydney University and CSIRO, one of the authors on a new paper about ORCs, said only five odd radio circles have...

Although we usually have a pretty good handle on all the different kinds of blips and blobs detected by our telescopes, it would be unwise to assume we've seen everything there is to see out there in the big, wide Universe. Case in point: a new kind of signal spotted by radio telescopes, which has astronomers scratching their heads. Four of these strange objects have been detected. All of them are circular in shape, and three are particularly bright around the edges - like a ring, or a bubble that is more opaque around the edges. An international team of...

There's something unusual lurking out in the depths of space: Astronomers have discovered four faint objects that at radio wavelengths are highly circular and brighter along their edges. And they're unlike any class of astronomical object ever seen before. The objects, which look like distant ring-shaped islands, have been dubbed odd radio circles, or ORCs, for their shape and overall peculiarity. Astronomers don't yet know exactly how far away these ORCs are, but they could be linked to distant galaxies. All objects were found away from the Milky Way's galactic plane and are around 1 arcminute across (for comparison, the...