BUDAPEST, Hungary, Aug. 4 (UPI) -- An international team of astronomers say they've found the largest feature in the known universe, a ring of nine gamma-ray bursts measuring five billion light-years across.
Gamma-ray bursts, or GRBs, are the brightest electromagnetic events in the universe -- thought to be the result of explosive high-mass stars collapsing into black holes. These extremely luminous and faraway events help astronomers map distant galaxies.
Each of the recently observed GRBs represent a galaxy, and together their explosive energy reveals a massive ring of galaxies -- the largest feature yet observed in the universe. The GRBs all appear to be a similar distance away, seven billion light-years from Earth. They appear in a circle measuring 36 degrees across, which translates to a feature roughly five billion light-years across.
"If the ring represents a real spatial structure, then it has to be seen nearly face-on because of the small variations of GRB distances around the object's center," Lajos Balazs, an astronomer at the Konkoly Observatory in Budapest, Hungary, explained in a press release. "The ring could though instead be a projection of a sphere, where the GRBs all occurred within a 250 million year period, a short timescale compared with the age of the universe."
The size of the observed feature calls into question current models of universe. Modern theories suggest that the universe, when viewed on a large enough scale, is uniform -- matter evenly distributed and without irregularities.
It's called the "cosmological principle," and it's based on the idea that material was scattered by the Big Bang. The principle, as it stands, puts the theoretical limit on the size of structures at 1.2 billion light-years.
"If we are right, this structure contradicts the current models of the universe," Balazs said. "It was a huge surprise to find something this big -- and we still don't quite understand how it came to exist at all."
Researchers say they now need to go back to the drawing board. Further research must either explain how current models can account for such a large structure, or scientists will be forced to reconsider the models that currently explain the evolution of the cosmos.
While other larger structures have called the cosmological principle in to doubt in recent years, the latest discovery -- detailed in the Monthly Notices of the Royal Astronomical Society -- is an anomaly that astronomers and cosmologists won't be able to ignore.