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Largest structure in the universe would take four billion years to cross, say astronomers

Astronomers from the University of Central Lancashire have spotted the largest structure in the universe.

How big is the large quasar group? Astronomers say that it would take a spacecraft moving at the speed of light approximately 4 billion years to cross it.

“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,” says Dr. Roger Clowes from the UCLan’s Jeremiah Horrocks Institute. “This is hugely exciting – not least because it runs counter to our current understanding of the universe. The universe doesn’t seem to be as uniform as we thought.”

According to astronomers, quasars are galaxies form the early days of the universe that undergo brief periods of very high brightness that make them visible across great distances. These “brief” periods actually last 10-100 million years (which is considered brief, astronomically speaking.)

For more than 30 years, astronomers have known that quasars typically group together in large structures, creating large quasar groups or LQGs.

The research team, led by Dr. Clowes, says that a LQG is so significant in size that it also challenges the Cosmological Principle, which is the assumption that the universe, when seen at a sufficiently large scale, appears that same no matter where you are looking at it from.

The modern theory of cosmology, which is based on Albert Einstein’s work, relies on the assumption of the Cosmological Principle, The Principle is assumed but has never been demonstrated observationally “beyond reasonable doubt,” say astronomers.

The Milky Way Galaxy is approximately 2.5 million light-years away from its nearest neighbor, the Andromeda Galaxy. Whole clusters of galaxies can be 6-10 million light years across but LQGs can be 650 million light years or more across. Astronomers note, however, that the Cosmological Principle and the modern theory of cosmology suggest that astrophysicists should not be able to locate a structure bigger than 1.2 billion light years.

“Travelling at the speed of light, it would still take 4 billion light years to cross,” Dr. Clowes adds. “This is significant not just because of its size but also because it challenges the Cosmological Principle, which has been widely accepted since Einstein. Our team has been looking at similar cases which add further weight to this challenge and we will be continuing to investigate these fascinating phenomena.”

The longest dimension of the structure found by Dr. Clowes and his team is 1,650 times bigger than the distance from the Milky Way to Andromeda.

The study’s findings will be described in detail in the journal Monthly Notices of the Royal Astronomical Society.