Astronomers Discover Largest Known Structure in Universe

A team of astronomers have discovered the largest structure ever seen in the universe - a large quasar group (LQG).

Quasars are a distant active galactic nuclei of galaxies that become really bright, making them visible across large distances. The brightness tends to prevail for at least 10-100 million years.

These quasars are known to group together into clumps or structures of large sizes, forming huge groups.

Now, an international team of astronomers has found the largest quasar group yet, comprising of 73 quasars and stretching 4 billion light years across at its widest point, according to Space.com. This means that a vehicle traveling at a speed of light will take four billion years to cross it.

The newly-found quasar group is 1,600 times larger than the distance between our Milky Way galaxy and its nearest neighbor, the Andromeda Galaxy. The Milky Way and the Andromeda Galaxy are separated by 2.5 million light years.

This new discovery challenges Albert Einstein's cosmological principle which has been widely accepted by scientists. According to Einstein's theory, when viewed on a large scale, the universe should look the same irrespective of the direction from which the observer looks.

Based on this principle, estimations suggest that a structure should not be larger than 1.2 billion light years across (370 Megaparsecs (Mpc)). But the new quasar structure, on an average, is 1.63 billion light years across. The quasar group is elongated and hence its longest dimension is 1200 Mpc, which means that it stretches across 4 billion light years, according to Planetsave.com. 

"While it is difficult to fathom the scale of this LQG, we can say quite definitely it is the largest structure ever seen in the entire universe. This is hugely exciting - not least because it runs counter to our current understanding of the scale of the universe," Dr. Roger Clowes, from University of Central Lancashire's Jeremiah Horrocks Institute, said in a statement.

The team is looking at similar cases to understand the phenomena.

The findings of the study appear in the monthly notices of the Royal Astronomical Society.