It’s pretty hard to fathom just how big some things in the universe are, but this possible feature is so large that it borders on the ridiculous.
Astronomers think they have found a ring of nine gamma ray bursts (GRBs) inside galaxies that, together, measure 5 billion light-years across. For a comparison, that’s about 50,000 times bigger than the Milky Way, or more than one-ninth the size of the observable universe. The research was published in the journal Monthly Notices of the Royal Astronomical Society.
A GRB is an intense flash of gamma rays caused by a supernova, the dramatic death of a fiery star, and thus their detection indicates the presence of a galaxy – suggesting all nine of the GRBs are in separate galaxies. They are the brightest electromagnetic events in the universe, releasing more energy in a few seconds than the Sun in its entire 10 billion-year lifetime, and thus they can be used to detect distant galaxies.
While it is not one physical whole structure, the Hungarian-American team who made the discovery think the nine galaxies are gravitationally bound to each other – just as our Local Group contains the Milky Way and a few dozen other galaxies.
In this case, all the GRBs studied by a variety of observatories are about 7 billion light-years away from Earth, suggesting that we are seeing the structure “face on.” Alternatively, we may be seeing a projection of a “sphere.”
But there’s one problem. The structure, if confirmed, would break our current models of how large things can be; a previous theoretical limit stood at 1.2 billion light-years. On large scales, the cosmos should be uniform and not have structures like this.
“If we are right, this structure contradicts the current models of the universe,” said Professor Lajos Balazs of Konkoly Observatory in Budapest, the lead author on the paper, in a statement. “It was a huge surprise to find something this big – and we still don’t quite understand how it came to exist at all.”
And it may not even be the biggest structure at all, even if it is confirmed. Another contender, the Hercules-Corona Borealis Great Wall, is a similar concentration of GRBs – in this case 19 – that could span more than 10 billion light-years in size.