The Andromeda Galaxy is named after the mythological Princess Andromeda is a spiral galaxy approximately 780 kiloparsecs (2.5 million light-years) from Earth, and the nearest major galaxy to our own galaxy Milky Way.
The 2006 observations by the Spitzer Space Telescope revealed that the Andromeda Galaxy contains approximately one trillion stars, more than twice the number of the Milky Way’s estimated 200-400 billion stars.
The Andromeda Galaxy, spanning approximately 220,000 light years, is the largest galaxy in our Local Group, which is also home to the Triangulum Galaxy and other minor galaxies. The Andromeda Galaxy’s mass is estimated to be around 1.76 times that of the Milky Way Galaxy.
The Milky Way and Andromeda galaxies are expected to collide in ~4.5 billion years, merging to form a giant elliptical galaxy or a large disc galaxy.
With the advancement in technology, now we can get more clearer and beautiful photos of space and even galaxies as well.
This is a Andromeda Galaxy Then And Now photo which shows how the Andromeda Galaxy looked back in 1888 when Isaac Roberts took photos of it and how this galaxy looks now when NASA’s Galaxy Evolution Explorer showed it in 2016.