2004/01/02 by Charles H. Lineweaver, Yeshe Fenner, B. K. Gibson +1 · 16 citations
Physics and Astronomy · #Astro and Planetary Science #Space Science and Extraterrestrial Life #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1126/science.1092322
published as Science 303 (2004) 59-62 · 9 pages, 4 figs. Published in Science, 2 January 2004
openalex publication_date 2004/01/02 · arxiv created 2004/01/05 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We modeled the evolution of the Milky Way to trace the distribution in space and time of four prerequisites for complex life: the presence of a host star, enough heavy elements to form terrestrial planets, sufficient time for biological evolution and an environment free of life-extinguishing supernovae. We identified the Galactic habitable zone (GHZ) as an annular region between 7 and 9 kiloparsecs from the Galactic center that widens with time and is composed of stars that formed between 8 and 4 billion years ago. This GHZ yields an age distribution for the complex life that may inhabit our Galaxy. We found that 75% of the stars in the GHZ are older than the Sun.