Saraswati is the newly discovered supercluster that is 600 million light-years across. The Saraswati supercluster is way more distant in contrast to the other massive superclusters that have been spotted so far.

Saraswati, an enormous supercluster of galaxies, is discovered by a team of Indian researchers from the Indian Institute of Science Education and Research (IISER)and Inter-University Centre for Astronomy & Astrophysics (IUCAA) and in Pune, India, along with members of two other Indian universities. Below is a brief explainer on how the supercluster was discovered and its background.

What are superclusters?

Superclusters are the largest coherent structures in the universe. There are clusters of galaxies with associated dark matter and gas. Large groups of clusters - linked by galactic filaments and separated by voids - form the superclusters. The first enormous supercluster that was discovered was the Shapley supercluster.

The Saraswati supercluster versus the Milky Way

Saraswati, the newly discovered supercluster, is 600 million light-years across, while the Milky Way is about 150,000 light-years across.

Where does the supercluster lie in the sky?

The Saraswati supercluster lies in the Stripe 82 of the SDSS (Sloan Digital Sky Survey). It is approximately 4,000 million light-years away from our planet. It is located in the constellation of Pisces.

What is the “Stripe 82 region of Sloan Digital Sky Survey”?

SDSS is an ambitious plan that aims to produce a digital 3-dimensional map of the universe. It began in 2000, and over a period of eight years, it managed to map more than a quarter of the sky, nearly 930,000 galaxies so far.

Significance of the discovery

Spotting a supercluster that is nearly 4000 million light-years away implies you are looking at a light that is travelling from four billion years ago. Since it is believed that the universe is 13.8 billion years old, it means we are looking at light from the time the universe was nearly 10 billion years old, nearly 70 per cent of its present age.

Which was the first supercluster discovered by the Indians?

Professor Somak Raychaudhury, who is currently the director of IUCAA, Pune, had discovered a supercluster while conducting his PhD thesis work at the University of Cambridge. The supercluster was named "Shapley Supercluster," after the conducting American astronomer who first coined the term cluster.

The researchers have revealed that the massive Saraswati supercluster is estimated to possess the mass equivalent of over 20 million Suns.