The Saraswati supercluster, 4 billion light years away from us, has 43 galaxies, discover Indian astronomers.

In a significant discovery, a team of Indian astronomers have identified a previously unknown, extremely large supercluster of galaxies located in the direction of constellation Pisces.

The supercluster of 43 galaxies, which they named “Saraswati”, is one of the largest known structures in the nearby universe, and is 4 billion light years away from us and may contain the mass equivalent of over 20 million billion suns.

A supercluster is a chain of galaxies and galaxy clusters, bound by gravity, often stretching to several hundred times the size of clusters of galaxies, consisting of tens of thousands of galaxies. The Saraswati supercluster, for instance, extends over a scale of 600 million light years.

The Milky Way, the galaxy we are in, is part of a supercluster called the Laniakea Supercluster, announced in 2014 by Brent Tully at the University of Hawaii and collaborators.

The Saraswati discovery was made by astronomers from India’s Inter University Centre for Astronomy and Astrophysics (IUCAA) and the Indian Institute of Science Education and Research (IISER), both in Pune, and members of two other Indian universities. IUCAA is an autonomous institution set up by the India to promote the nucleation and growth of active groups in astronomy and astrophysics at Indian universities.

“The Saraswati supercluster is observed as it was when the universe was 10 billion years old,” IUCAA said in the statement. Thus, the findings could push researchers to rethink the popular theories of how the universe got its current form.

“The long-popular ‘cold dark matter’ model of the evolution of the universe predicts that small structures like galaxies form first, which congregate into larger structures. Most forms of this model do not predict the existence of large structures such as the Saraswati Supercluster within the current age of the universe. The discovery of these extremely large structures thus force astronomers into re-thinking the popular theories of how the universe got its current form, starting from a more-or-less uniform distribution of energy after the Big Bang,” the statement said.