Ancient Venus and Earth may have been similar in crucial ways for the development of life, such as liquid water oceans, land–ocean interfaces, favorable chemical ingredients, and energy pathways. If life ever developed on, or was transported to, early Venus from elsewhere, it might have thrived, expanded, and then survived the changes that have led to an inhospitable surface on Venus today. The Venus cloud layer may provide a refugium for extant life that persisted from an earlier more habitable surface environment. We introduce the Venus Life Equation (VLE)—a theory and evidence-based approach to calculate the probability of extant life on Venus, L, using three primary factors of life: Origination, Robustness, and Continuity, or L = O · R · C. We evaluate each of these factors using our current understanding of Earth and Venus environmental conditions from the Archean to the present. We find that the probability of origination of life on Venus would be similar to that of Earth, and argue that the other factors should be nonzero, comparable with other promising astrobiological targets in the solar system. The VLE also identifies poorly understood aspects of Venus that can be addressed by direct observations with future exploration missions.

中文翻译：

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金星生命方程

古代金星和地球可能在生命发展的关键方面很相似，例如液态水海洋、陆地-海洋界面、有利的化学成分和能量途径。如果生命曾经在早期的金星上发展或从其他地方被运送到早期的金星，它可能会蓬勃发展、扩张，然后在导致今天金星表面不适宜居住的变化中幸存下来。金星云层可能为从早期更宜居的地表环境中持续存在的现存生命提供避难所。我们介绍了金星生命方程 (VLE)——一种基于理论和循证的方法来计算金星现存生命的概率，L，使用生命的三个主要因素：起源、稳健性和连续性，或 L  =  O  ·  R  · C. 我们使用我们目前对地球和金星从太古代到现在的环境条件的理解来评估这些因素中的每一个。我们发现金星上生命起源的概率与地球相似，并认为其他因素应该是非零的，与太阳系中其他有希望的天体生物学目标相当。VLE 还确定了金星的一些知之甚少的方面，这些方面可以通过未来探索任务的直接观测来解决。