Galactic habitable zone
Galactic habitable zone is a habitable zone in astronomy and astrobiology, where life is most likely to occur in any galaxy. The concept of a habitable zone uses many things, like metalicity, presence of chemicals that life requires, and uses these to find out which regions of a galaxy are more likely to form rocky planets, that can develop simple life, and provide a suitable environment for this life to evolve and grow. According to research published in August 2015, very large galaxies may favor the development of habitable planets more than small galaxies like the Milky Way.