Indian astronomers have discovered a massive super cluster of galaxies,
-the Saraswati supercluster.
It is about 4 billion light years from Earth.
It is one of the largest supercluster galaxies, that has been discovered.
It is also the most distant supercluster galaxy, that we know.
A galaxy is a cluster of stars.
Our sun is one of the stars, in the milky way galaxy.
A group of galaxies is called as a galaxy cluster.
When a galaxy cluster is unusually large we call it as a super cluster galaxy.
Super cluster galaxies are very rare.
This discovery of a rare, and most distant galaxy,
is named after the ancient Sarasvati river.
The Saraswati supercluster, spans a distance of 600 million light years.
It has 43 galaxy cluster, with about 400 galaxies.
It is estimated that it hosts about 20 million billion stars.
There are only a few supercluster galaxies of comparable size.
For example, the shapely concentration, and the Sloan Great Wall.
What makes Saraswati unique, is the distance of 4 billion light years.
It is the first time that we have discovered a supercluster so far away.
Even the shapely is about 8 to 10 times closer.
Universe is about 13.9 billion years old.
If something is 4 billion light years away,
it means that we are witnessing something,
that the universe was only 10 billion years old.
This is considered as a early universe.
Supercluster galaxies grow extremely slowly.
It might take billions of years, to form a supercluster.
Scientists are puzzled how Saraswati could have been formed,
so early in the life of the universe.
Scientist believe that a balance between dark matter,
and dark energy, can produce large superclusters.
But, they are not able to explain the size and time of Saraswati.
As of now, Saraswati is a mystery.