论文标题
超越淡蓝色点：如何在类似地球的行星上寻找可能的生物签名
Beyond a pale blue dot : how to search for possible bio-signatures on earth-like planets
论文作者
论文摘要
从太阳系外部观察的地球将被视为卡尔·萨根（Carl Sagan）所创造的淡蓝色点。为了检测在习惯区域中发现的几个地球上生命存在的可能签名，必须开发和建立一种将行星表征为仅仅是淡蓝色点以外的东西的方法。我们特别注意根据地球的旋转，点颜色的周期性变化。由于行星表面的大规模不均匀分布，该点的反射光包含不同的颜色成分，这些颜色成分对应于覆盖行星表面的土地，海洋，冰和云。如果我们将点的颜色分解为几个原理成分，则可以识别不同表面成分的存在。此外，众所周知，地球上的植被具有显着的反射特征。在波长大于760nm的波长下，反射显着增强，这被称为植被的红色边缘。如果可以识别淡蓝色点中相应的颜色签名，则可以用作对生命存在的独特探针。我将描述该方法对未来太空任务的可行性，并从天体物理学家的角度考虑了天体生物学的方向。
The Earth viewed from outside the Solar system would be identified merely like a pale blue dot, as coined by Carl Sagan. In order to detect possible signatures of the presence of life on a second earth among several terrestrial planets discovered in a habit-able zone, one has to develop and establish a methodology to characterize the planet as something beyond a mere pale blue dot. We pay particular attention to the periodic change of the color of the dot according to the rotation of the planet. Because of the large-scale inhomogeneous distribution of the planetary surface, the reflected light of the dot comprises different color components corresponding to land, ocean, ice, and cloud that cover the surface of the planet. If we decompose the color of the dot into several principle components, in turn, one can identify the presence of the different surface components. Furthermore, the vegetation on the earth is known to share a remarkable reflection signature; the reflection becomes significantly enhanced at wave-lengths longer than 760nm, which is known as a red-edge of the vegetation. If one can identify the corresponding color signature in a pale blue dot, it can be used as a unique probe of the presence of life. I will describe the feasibility of the methodology for future space missions, and consider the direction towards astrobiology from an astrophysicist's point of view.
