A South African radio telescope has captured the clearest image yet of a massive and mysterious space object.

Sixteen times larger than our Milky Way galaxy, or about a million light years across, the so-called “odd radio circle†has fascinated astronomers since it was first discovered in 2019.

“People often want to explain their observations and show that it aligns with our best knowledge,†astronomer Dr. Jordan Collier said in a . “To me, it’s much more exciting to discover something new, that defies our current understanding.â€

Collier of South Africa’s compiled the image of the gigantic glowing rings with the help of the MeerKAT radio telescope, which consists of 64 dish antennas. Only five odd radio circles have been found since first being discovered with a similar Australian radio telescope in 2019. Odd radio circles, or ORCs for short, are not visible with optical, infrared or x-ray telescopes.

While there is no explanation for what causes odd radio circles, the new data apparently shows spherical rings centred around a galaxy where only a roundish blob was previously visible. That added detail has helped researchers narrows it down to three leading theories: they could be the aftermath of a huge explosion at the centre of a galaxy, powerful jets of energy shooting out of a galaxy’s centre, or the shock wave from the formation of stars.

“We know [odd radio circles] are rings of faint radio emissions surrounding a galaxy with a highly active black hole at its centre, but we don’t yet know what causes them, or why they are so rare,†astrophysicist Dr. Ray Norris said.

Along with Collier, Norris of Australia’s Western Sydney University was part of the international team of researchers who published their findings on the odd radio circle in the peer-reviewed British journal .