
Astronomers have found a structure in the universe so huge, that current cosmological theory says it shouldn't exist

A US-Hungarian team recently discovered a ring of nine gamma ray bursts, in nine distant galaxies, 5 billion light years across.

For comparison, our galaxy is just a hundred thousand light-years across.

Gamma-ray bursts are the brightest objects in the universe, releasing as much energy in a few seconds as the sun does over its 10 billion year lifetime.

A US-Hungarian team recently discovered a ring of nine gamma ray bursts, in nine distant galaxies, 5 billion light years across. An image of the distribution of gamma-ray bursts (GRBs) on the sky at a distance of 7 billion light years, centred on the newly discovered ring. The positions of the GRBs are marked by blue dots and the Milky Way is shown for reference, running from left to right

WHAT ARE GAMMA-RAY BURSTS? Gamma-ray bursts are the most powerful explosions the universe has seen since the Big Bang. They occur around once per day and are brief, but intense, flashes of gamma radiation. They come from all directions and last from milliseconds to a few hundred seconds. Recent evidence from recent satellites like Swift and Fermi indicate that the energy behind a gamma-ray burst comes from the collapse of matter into a black hole. What is known, however, is that their huge luminosity helps astronomers to map out the location of distant galaxies, something the team exploited to find the structure. Advertisement

Recent evidence from recent satellites like Swift and Fermi indicate that the energy behind a gamma-ray burst comes from the collapse of matter into a black hole.

Their huge luminosity helps astronomers to map out the location of distant galaxies, something the team exploited to find the structure.

The Gamma-ray bursts (GRBs) that make up the newly discovered ring were seen using a combination of space- and ground-based observatories.

They appear to be at very similar distances from us – around seven billion light years – in a circle 36° across on the sky, or more than 70 times the diameter of the full moon.

This suggests that the ring is more than 5 billion light years across.

According to Professor Lajos Balazs of Konkoly Observatory in Budapest, there is only a 1 in 20,000 probability the GRBs being are in this distribution by chance.

Modern astrophysical models suggest that the upper size limit for cosmic structures should be no more than 1.2 billion light-years.

The newly discovered ring is almost five times as large.

The structure also defies a widely accepted cosmological principle, which says that the universe would look uniform when observed at the largest scales.

'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 centre,' said Professor Balazs.

'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.'

Gamma-ray bursts (artist's impression pictured) are the most powerful explosions the universe has seen since the Big Bang. According to Professor Lajos Balazs of Konkoly Observatory in Budapest, there is only a 1 in 20,000 probability the gamma-ray bursts seen in this huge ring are in their formation by chance

A spheroidal ring projection would mirror the strings of clusters of galaxies seen to surround voids in the universe.

The newly discovered ring is however at least ten times larger than known voids.

Professor Balazs comments: 'If we are right, this structure contradicts the current models of the universe.

'It was a huge surprise to find something this big – and we still don't quite understand how it came to exist at all.'

The team now want to find out more about the ring, and discover whether the known processes for galaxy formation and large scale structure could have led to its creation.

They suggest astronomers may need to radically revise their theories of the evolution of the cosmos.