Asked by: David Blanchflower, Newcastle upon Tyne
The largest known structure in the Universe is called the ‘Hercules-Corona Borealis Great Wall’, discovered in November 2013. This object is a galactic filament, a vast group of galaxies bound together by gravity, about 10 billion light-years away.
This cluster of galaxies appears to be about 10 billion light-years across; more than double the previous record holder! Astronomers were able to determine the size of the structure by mapping gamma-ray bursts (pictured) from this group of galaxies.
In fact, this object is so big it’s a bit of an inconvenience for astronomers. Modern cosmology hinges on the principle that matter should appear to be distributed uniformly if viewed at a large enough scale. Astronomers can’t agree on exactly what that scale is but it is certainly much less than the size of the Hercules-Corona Borealis Great Wall. The huge distance also implies this object was in existence only 4 billion years after the Big Bang.