In astrobiology and planetary astrophysics, the galactic habitable zone is the region of a galaxy in which life might most likely develop. The concept of a galactic habitable zone analyzes various factors, such as metallicity and the rate and density of major catastrophes such as supernovae, and uses these to calculate which regions of a galaxy are more likely to form terrestrial planets, initially develop simple life, and provide a suitable environment for this life to evolve and advance. According to research published in August 2015, very large galaxies may favor the birth and development of habitable planets more than smaller galaxies such as the Milky Way. In the case of the Milky Way, its galactic habitable zone is commonly believed to be an annulus with an outer radius of about 10 kiloparsecs (33,000 ly) and an inner radius close to the Galactic Center.
The impact of supernovae on the extent of the galactic habitable zone has been extensively studied.
The Milky Way is the galaxy that includes the Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars that cannot be individually distinguished by the naked eye.
The Galactic Center as seen from Earth's night sky (featuring the telescope's laser guide star). Listed below is Galactic Center's information.
The Milky Way as seen from a dark site with little light pollution
Photograph of the "Great Andromeda Nebula" from 1899, later identified as the Andromeda Galaxy
Bright X-ray flares from Sagittarius A* (inset) in the center of the Milky Way, as detected by the Chandra X-ray Observatory.