Cockell Charles S
UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh , Edinburgh, UK .
Astrobiology. 2014 Feb;14(2):182-203. doi: 10.1089/ast.2013.1106. Epub 2014 Feb 7.
Beginning from two plausible starting points-an uninhabited or inhabited Mars-this paper discusses the possible trajectories of martian habitability over time. On an uninhabited Mars, the trajectories follow paths determined by the abundance of uninhabitable environments and uninhabited habitats. On an inhabited Mars, the addition of a third environment type, inhabited habitats, results in other trajectories, including ones where the planet remains inhabited today or others where planetary-scale life extinction occurs. By identifying different trajectories of habitability, corresponding hypotheses can be described that allow for the various trajectories to be disentangled and ultimately a determination of which trajectory Mars has taken and the changing relative abundance of its constituent environments.
从两个看似合理的起点——无人居住或有人居住的火星——出发，本文探讨了火星宜居性随时间变化的可能轨迹。在无人居住的火星上，轨迹遵循由不适宜居住环境和无人居住栖息地的丰度所决定的路径。在有人居住的火星上，加入第三种环境类型——有人居住的栖息地，会产生其他轨迹，包括地球至今仍有人居住的轨迹，或发生行星规模生命灭绝的其他轨迹。通过识别宜居性的不同轨迹，可以描述相应的假设，从而能够理清各种轨迹，并最终确定火星走了哪条轨迹，以及其组成环境相对丰度的变化情况。
