In September 2019, my colleague Anna Kapinska gave a presentation showing interesting items found while browsing our new radio astronomical data. He started seeing very strange shapes that could not easily fit for any type of object.
Among them, as labeled by Anna WTF?, Roaming the space like a cosmic smoke ring, was a picture of a ghostly circle of radio emission. None of us had ever seen anything like this before, and we had no idea what it was. A few days later, our colleague Emil Lane found another one, which was even more frightening than Anna’s.
Ana and Emil were examining new images for our Pilot Observation of the Universe (EMU) project created with CSIRO’s revolutionary new Australian Square Kilometer Aareth Pathfinder (ASKAP) telescope.
The EMU plans to investigate parts of the universe where no telescopes have been previously. It can do this because ASKAP can very quickly survey large parts of the sky, which already reach depths in small areas of the sky, and are particularly sensitive to unconsciousness, Spreading things like
I speculated a few years ago that the discovery of the unknown would probably lead to an unexpected discovery, which I have called WTF. But none of us expected something unexpected, such a quick discovery. Due to the huge data volume, I expected searches to be made using machine learning. But these discoveries were made with the old-fashioned eyeball.
Read more: Expect the unexpected from the big-data boom in radio astronomy
Our team searched the rest of the eye data, and we found some more mysterious round blobs. We dubbed them ORCs, which stands for “odd radio circle”. But the big question is: “What are they?”
At first we suspected an imaging artifact, perhaps caused by a software error. But we soon confirmed that they were real, using other radio telescopes. We still don’t know how big or far they are. Our galaxy may contain those objects, perhaps a few light-years across, or they may be in the universe and perhaps millions of light-years away.
When we look at images taken with optical telescopes in the ORC position, we see nothing. Radio emission rings are probably caused by clouds of electrons, but why don’t we see anything in the wavelength of light? We do not know, but every astronomer dreams of finding such a puzzle.
Read more: Australian Square Kilometer Array Pathfinder Finally Hits Big Data Highway
We know what they are not
We have ruled out several possibilities for ORCs.
Could they be supernova remnants, left behind by clouds of debris when a star explodes in our galaxy? No, they are far from most stars of the Milky Way and have a lot of them.
Could they be radio emission rings sometimes seen by intense bursts of star formation in galaxies? not again. We do not see any underlying galaxy that will host star formation.
Could they be the giant lobes of radio emissions we see in radio galaxies, caused by the jet of electrons emanating from the atmosphere of a supermassive black hole? Not likely, because ORCs are very distinctly spherical, unlike the tangled clouds we see in radio galaxies.
Could they be Einstein rings, in which radio waves from a distant galaxy are being tilted into a circle by the gravitational field of a group of galaxies? Still not. The ORCs are very symmetric, and we do not see clusters at their center.
A real mystery
In our paper about ORCs, which is forthcoming in the publications of the Astronomical Society of Australia, we walk through all the possibilities and conclude that these enigmatic temptations do not appear to be the ones we already know.
So we need to detect things that do not yet exist, but have not yet been seen, such as a huge shockwave from some explosion in a distant galaxy. Such explosions can be caused by sharp radio bursts or collisions of neutron stars and black holes that produce gravitational waves.
Read more: How far did we stop in a galaxy instead of a fast radio burst, far away
Or maybe they are something else entirely. Two Russian scientists have also suggested that ORCs may be the “throat” of wormholes in spacetime.
Whatever we have found so far, we estimate that there are about 1,000 orcs in the sky. My colleague Briebel Koribalski noted that the search is now on with telescopes around the world, to find more ORCs and understand their cause.
This is a difficult task, as ORCS are very dull and difficult to find. Our team is churning out all these ideas and more, looking forward to the Eureka moment when one of us, or perhaps someone else, suddenly has a flash of inspiration that solves the puzzle.
This is an exciting time for us. Most astronomical research aims to refine our knowledge of the universe or to test theories. Very rarely do we get to challenge a new type of object that no one has seen before, and is trying to figure out what it is.
Is this a completely new phenomenon, or something we already know about but seen in a strange way? And if it is indeed completely new, how does it change our understanding of the universe? Look at this place!