The Milky Way is our home galaxy. It began to form twelve billion years ago. The Milky Way galaxy is a part of fifty galaxies that is referred as the local group. Moreover, the local galaxy group itself comes under a large group of galaxies. The larger group is referred as Virgo Supercluster. The Milky Way galaxy is a barred spiral galaxy with one spur and four arms in its diskette and recently a new outer arm was discovered. The mass of the Milky Way galaxy is four hundred to eight hundred billion solar masses. It contains at least four hundred billion stars. It comes under a local group.
It is estimated that Milky Way galaxy will smash together with Andromeda galaxy. The astronomers have estimated five billion years for the chances of collision. Some astronomers mention as a binary system. The dust, gas, and stars of Milky Way galaxy orbit in the centre. They orbit at a speed rate of two hundred kilometres per second.
The Black Hole
There is a super massive black hole in the centre core of the Milky Way galaxy. The black hole is referred as Sagittarius A. It is said that Sagittarius A has the mass of 2.6 million stars. The Milky Way galaxy grows by merging and joining with other galaxies in the universe through the time. It is gulping up substance from Magellanic Clouds. Sagittarius Dwarf Spheroidal is a small galaxy and Milky Way galaxy is currently getting stars from that galaxy. The Sagittarius Dwarf Spheroidal is actually small in size.
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