its not the universe it's called a cluster.
The Universe
For starters, if there were no separation between two (or more) galaxies, it would be considered a single galaxies, not two or more. The reason matter is clumped together into galaxies at all (with separations in between) is because of gravity - gravity tends to do that, i.e., to clump things together.
It highly likely that astronomers will name all the designations of the 100 billion galaxies in the universe in this lifetime.
Yes, all galaxies have gravity. Gravity is a fundamental force that exists everywhere in the universe, including within and between galaxies. It is responsible for holding galaxies together, as well as determining their structure and motion.
Astronomers can name all the designations of the 100 billion galaxies in the universe using their mass, age, and metallicity.
Spiral Galaxies
Galaxies that travel together through space are called galaxy groups or galaxy clusters. These are systems of galaxies bound together by gravity.
The universe contains all the stars and galaxies in existence. Stars are massive celestial bodies that emit light and heat, while galaxies are vast systems of stars, gas, dust, and dark matter bound together by gravity. Together, they make up the incredible tapestry of the cosmos.
In theory, all galaxies originate from the Big Bang, which is the name that describes the explosion that propelled all matter into the cosmos. All galaxies are moving. All galaxies produce energy like light and gravity. Think of galaxies like you would human beings. Although very different in some ways, they are mostly the same.
That's called a supercluster.
All stars and galaxies are in the universe.
A super massive Black hole present in the centre of almost all galaxies have tedency to bind up all the things . Our milky also have super massive black hole in it's centre .