[论文解读] Nodes: A Proposed Solution to Fermi's Paradox

John Gertz|arXiv (Cornell University)|Feb 14, 2018

Space Science and Extraterrestrial Life参考文献 5被引用 7

一句话总结

本文提出，高级外星文明会形成一个相互连接的‘节点’银河网络，共享知识并探测新兴的科技生命。这些节点通过窄带信号进行通信，除非直接瞄准，否则从地球无法探测到，这解释了费米悖论——我们目前尚未处于银河中活跃的通信路径之中。

ABSTRACT

Within the SETI community, a school of thought holds that ET might prefer to send information physically in so-called "probes," rather than by radio or optical beacon, in effect, a message in a bottle. In this paper, a related solution to Fermi's Paradox (also known as the "Great Silence") is proposed whereby ET civilizations aggregate knowledge into a system of "nodes," interspersed throughout the galaxy. Each node explores and serves the local star systems, detecting through its exploration non-technological life, and enlisting newly emergent technological civilizations, such as ourselves, into its central system. Each node would download information to new member civilizations and upload information from those civilizations, passing it along to its immediately adjacent nodes, such that new information would pass through the entire galaxy at near light speed. The most local node would not be directly detectible by us until it signaled Earth in response to a detection of its artificial electromagnetic (EM) leakage. This is because Earth would not be in the narrow beam of the signal pathways between our local node and its adjacent nodes, nor between the local node and other local civilizations, while the spillover signal strength of far distant nodes would be too weak to be detectable. Thus, the Great Silence of the galaxy is simply the result of the fact that Earth is not currently situated within a communications pathway in an otherwise well interconnected galaxy.

研究动机与目标

• 通过提出一种机制来解决费米悖论，解释为何尚未探测到外星文明的信号。
• 解释尽管存在高概率，地球为何至今未探测到智慧生命。
• 提出一个模型，即高级文明形成去中心化、自维持的知识共享节点网络。
• 阐明为何此类网络对地球上的SETI探测手段保持不可探测。
• 提出缺乏探测结果的原因在于地球处于节点之间活跃通信路径之外。

提出的方法

• 提出一个‘节点’的银河网络——自主系统，负责探索并整合新的科技文明。
• 每个节点探测非科技生命，并将像地球这样的新兴科技文明招募进网络。
• 信息通过窄带电磁信号在节点间传输，最大限度减少可探测的信号溢出。
• 新加入的文明从其本地节点接收数据，并将新发现上传至相邻节点。
• 信号高度定向，因此只有处于节点间链路波束路径内的文明才能探测到。
• 由于地球未与任何活跃的节点间通信路径对齐，因此保持不可探测。

实验结果

研究问题

• RQ1 尽管外星文明存在的可能性极高，为何地球尚未探测到任何信号？
• RQ2 一个去中心化、自维持的高级文明网络是否能解释不可探测信号的缺失？
• RQ3 在何种条件下，银河通信网络会对地球观测者保持不可探测？
• RQ4 像地球这样的新兴科技文明如何被整合进更大的星际知识网络？
• RQ5 信号波束的几何结构在星际通信可探测性中起什么作用？

主要发现

• 未探测到外星信号并非因为高级文明不存在，而是因为地球目前不在节点之间的活跃通信路径中。
• 节点间使用的窄带信号溢出极小，对地球射电望远镜而言近乎不可见。
• 该网络通过节点间链路实现接近光速的信息传输。
• 地球只有在其本地节点响应地球人为电磁泄漏信号时才会变得可探测，而目前这种泄漏信号尚未被探测到。
• 该模型将‘大沉默’解释为空间与方向对齐的结果，而非生命的缺失。
• 该系统具备自维持与可扩展性，节点持续在银河范围内交换信息。