A team of astronomers has discovered the largest known structure in the Universe, a group of quasars (each an extremely bright and distant active galactic nucleus), which takes 4 billion light years to travel.
The incredibly huge scale of the group of "crescent stars" appears to defy Albert Einstein's Cosmological Principle, the assumption that the Universe is isotropic, the researchers announced.
Quasars, according to scientists, are the brightest objects in the Universe and are the nuclei of ancient galaxies.
"It has been known since 1982 that quasars tend to cluster into aggregates or 'structures' of surprisingly enormous dimensions, creating incredibly large quasar groups, or LQGs," the researchers report.
The recently discovered huge group of quasars measures 500 megaparsecs across (1 megaparsec equals 3.3 million light years).
Because the LQG group is elongated, its longest dimension is 1,200 megaparsecs, or 4 billion light-years, the astronomers explain.
This size is 1600 times greater than the distance from Earth's Milky Way to the nearest galaxy, Andromeda.
"Although it is difficult to understand the scale of this LQG, we can confidently say that it is the largest structure we have ever discovered in the Universe," says Roger Close, head of the research team at the University of Central Lancashire in the UK. "This discovery is extremely exciting because it challenges the current theory of the scale of the Universe.".
