How are galaxies important to our existence?
Fortunately, galaxies do not have any impact upon our existence. The importance of this is that if our Milky Way galaxy had merged with another major galaxy, it would end up as an elliptical galaxy instead of a spiral. Elliptical galaxies are older. Thus they contain stars with less metallicity. These stars do not favor the correct elements for life to evolve. The merger of galaxies also tends to vaporize the gasses within nebulae which are needed to form new stars. Older stars + less star formation = poor chances of life bearing planets. So the importance is that none have been close enough to merge with the Milky Way except for smaller dwarf galaxies which do no harm when absorbed by the Milky Way. When the Milky Way merges with Andromeda in another 3 billion years, man will no longer exist on planet Earth due to our Sun reaching its red giant stage. But after this merger, the end result will be an elliptical galaxy which will have far less potential for producing stars with life-bea
