The notion of a Galactic Habitable Zone (GHZ), or regions of the Milky Way galaxy that preferentially maintain the conditions to sustain complex life, has recently gained attention due to the detection of numerous exoplanets and advances made in understanding habitability on the Earth and other environments. We discuss what a habitable environment means on large spatial and temporal scales, which necessarily requires an approximated definition of habitability to make an assessment of the astrophysical conditions that may sustain complex life. We discuss a few key exoplanet findings that directly relate to estimating the distribution of Earth-size planets in the Milky Way. With a broad notion of habitability defined and major observable properties of the Milky Way described, we compare selected literature on the GHZ and postulate why the models yield differing predictions of the most habitable regions at the present day, which include: (1) the majority of the galactic disk; (2) an annular ring between 7-9 kpc, and (3) the galactic outskirts. We briefly discuss the habitability of other galaxies as influenced by these studies. We note that the dangers to biospheres in the Galaxy taken into account in these studies may be incomplete and we discuss the possible role of Gamma-Ray Bursts and other dangers to life in the Milky Way. We speculate how changing astrophysical properties may affect the GHZ over time, including before the Earth formed, and describe how new observations and other related research may fit into the bigger picture of the habitability of the Galaxy.
The habitability trade-off: Chemical decoupling and quenching in massive galaxies
Astronomical Observatory, Volgina 7, 11060 Belgrade, Serbia（天文台）；Faculty of Mathematics, University of Belgrade, Studentski trg 16, 11158 Belgrade, Serbia（贝尔格莱德大学数学系）
Postulating Exoplanetary Habitability via a Novel Anomaly Detection Method
BITS Pilani, K. K. Birla Goa Campus（印度博拉理工学院果阿分校）；CSIS and APPCAIR, BITS Pilani, K. K. Birla Goa Campus（印度博拉理工学院果阿分校CSIS与APPCAIR中心）；Indian Institute of Astrophysics（印度天体物理研究所）
Exploring the Sun's birth radius and the distribution of planet building blocks in the Milky Way galaxy: A multi-zone Galactic chemical evolution approach
An Agnostic Machine Learning Model of Photosynthetic Habitability
Digital Environment Research Institute (DERI)（数字环境研究研究所）；Queen Mary University of London（伦敦女王玛丽大学）；Department of Physics and Astronomy（物理与天文学系）；Franklin College of Arts and Sciences（法兰克林艺术与科学学院）；University of Georgia（佐治亚大学）；Institute of Agricultural Biology and Biotechnology（农业生物学与生物技术研究所）；National Research Council of Italy（意大利国家研究委员会）；Department of Chemistry（化学系）；Brandeis University（布兰迪大学）；Astronomy Unit（天文学单位）
Habitable from the start: How initial planetary formation conditions may create habitable worlds
University of Maryland（马里兰大学）；NASA Goddard Space Flight Center（美国国家航空航天局戈达德太空飞行中心）；Michigan State University（密歇根州立大学）；Auburn University（奥本大学）；Aix-Marseille University（艾克斯-马赛大学）
