Astronomers are baffled about four objects that were spotted in deep space by  massive radio telescopes, reports said.

LiveScience.com reported on Thursday that the highly circular objects that appear bright along the edges were discovered when astronomers reviewed archival data from radio telescopes in Australia and India.

Kristine Spekkens, an astronomer from the Royal Military College of Canada and Queen’s University, told the science website that the objects appear to be something not yet probed.

The objects were described as circular, “edge-brightened discs.” They do not “correspond to any known type of object.” Two of them are relatively close together, which could indicate some relation.

The face-on star-forming galaxy theory, for example, was dashed, in part, due to the “lack of measurable optical emission” in comparison to the radio emission.