The search for life, on and off our planet, can be done by conventional methods with which we are all familiar. These methods are sensitive and specific, and are often capable of detecting even single cells. However, if the search broadens to include life that may be different (even subtly different) in composition, the methods and even the approach must be altered. Here we discuss the development of what we call non-earthcentric life detection – detecting life with methods that could detect life no matter what its form or composition. To develop these methods, we simply ask, can we define life in terms of its general properties and particularly those that can be measured and quantified? Taking such an approach we can search for life using physics and chemistry to ask questions about structure, chemical composition, thermodynamics, and kinetics. Structural complexity can be searched for using computer algorithms that recognize complex structures. Once identified, these structures can be examined for a variety of chemical traits, including elemental composition, chirality, and complex chemistry. A second approach involves defining our environment in terms of energy sources (i.e., reductants), and oxidants (e.g. what is available to eat and breathe), and then looking for areas in which such phenomena are inexplicably out of chemical equilibrium. These disequilibria, when found, can then be examined in detail for the presence of the structural and chemical complexity that presumably characterizes any living systems. By this approach, we move the search for life to one that should facilitate the detection of any earthly life it encountered, as well as any non-conventional life forms that have structure, complex chemistry, and live via some form of redox chemistry.

中文翻译：

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在宇宙中寻找生命：解决非常规问题的非常规方法。

可以通过我们都熟悉的常规方法来寻找地球上和地球外的生命。这些方法灵敏且特异，通常能够检测甚至单个细胞。但是，如果搜索范围扩大到包括组成可能不同（甚至微妙不同）的生命，则必须改变方法甚至方法。在这里，我们讨论了所谓的非地球生命探测技术的发展，即以任何形式或成分都能探测到生命的方法来探测生命。我们简单地问，要开发这些方法，是否可以根据生命的一般属性，尤其是可以测量和量化的属性来定义生命？采用这种方法，我们可以使用物理和化学方法来寻找生命，以询问有关结构，化学成分，热力学和动力学的问题。可以使用识别复杂结构的计算机算法来搜索结构复杂性。一旦确定，就可以检查这些结构的各种化学特征，包括元素组成，手性和复杂化学性质。第二种方法包括根据能源（即还原剂）和氧化剂（例如可食用和呼吸的物质）定义我们的环境，然后寻找无法解释这种现象的化学平衡区域。发现这些不平衡现象后，可以详细检查可能存在于任何生命系统中的结构和化学复杂性。通过这种方法，我们将对生命的搜索转移到应该有助于发现它遇到的任何尘世生活的地方，