An international team of astronomers has found the largest structure ever in the universe.
The large quasar group is so big, it would take 4 billion years to cross it, travelling at the speed of light. By comparison, it would take just 2.5 million light years to get to the Andromeda Galaxy, our closest neighbour in the universe.
A staggering leap in size isn’t the only piece of cosmic lore the discovery has shattered, however.
“The structure we found is a few per cent, say 5 per cent, of the size of the observable universe. It becomes hard to say the universe is uniform,” lead author Dr. Roger Clowes of the University of Lancashire told Torstar News Service
The modern theory known as the Cosmological Principle, the work of Albert Einstein, says the universe is symmetrical: the same in all directions.
“Ours is the most dramatic challenge to that,” said Clowes.
What does that mean? It “upsets the foundation of everything we do.”
Clinging to the Cosmological Principle “makes life a lot simpler mathematically, so people have stuck with it for a long time, although it’s never been demonstrated beyond a reasonable doubt.”
The discovery, published in the journal of the Royal Astronomical Society, doesn’t punch holes in Einstein’s other theory of relativity, he said. It does, however, raise the red flag that science has been simplifying that theory by assuming one half of the universe is the same as the other half.
Science believed the biggest thing in the universe should be no bigger than 370 megaparsecs (1.2 billion light years). This thing is three times that.
What is it? Large quasar groups are supermassive black holes typically at the centre of galaxies.
This gigantic structure spotted by Clowes with work from astronomers at the University of Chile, the University of Oxford and California Institute of Technology, is a never-before seen cluster of 73 quasars.
Clowes’s earlier work in discovering large quasar groups has found structures “that have come close to challenging” the idea of a symmetrical universe. This one hits it out of the celestial ballpark.
“We were very surprised, of course, because it was so big. I sent the details over to my collaborator at the University of Chile and his response was ‘What is that?’”
Astronomers “saw” the structure, named Huge-LQG, when the universe was 5 billion years old, which was 9 billion years ago, said Clowes. Quasars typically last from 10 to 100 million years, a cosmic blip in time.
“There is a whole lot of universe beyond what we can actually see. We can only see what light has been able to travel in that time.”
While the discovery is the biggest challenge yet to cosmic thinking, Clowes knows his fellow astronomers are a cautious bunch who will want to see more evidence. So his next step, he said, is to flesh out six more examples of massive structures that punch more holes in our idea of the universe.