论文标题
扩展的宇宙文明中沟通的因果限制
A causal limit to communication within an expanding cosmological civilization
论文作者
论文摘要
如果一个文明开始进行高速层次的扩张，随着时间的流逝而发展到宇宙学的规模，则文明中偏远星系之间的沟通会由于所涉及的距离而造成极端的时间延迟。实际上，如果净膨胀速度V大于.26c，则由于存在因果地平线，因此这种文明的大部分最终体积根本无法发出家乡银河系的信号。我们根据家庭银河系的“对话”程度说明了这种文明的区域，并描述了几何形状如何取决于膨胀速度。最后，我们通过反思地平线以外的空间定居点的价值来结束，在那里，启动家庭星系永远无法观察到菌落。
If a civilization embarks on high-speed intergalactic expansion, growing to a cosmological scale over time, communication between remote galaxies in the civilization will incur an extreme time delay, due to the distance involved. Indeed, if the net expansion speed v is more than .26c, most of the final volume of such a civilization will not be able to signal the home galaxy at all, due to the presence of a causal horizon. We illustrate the regions of such a civilization according to the degree of "conversation" that is possible with the home galaxy, and describe how the geometry depends on expansion speed. We conclude by reflecting on the value of space settlement beyond the horizon, where colonies can never be observed by the initiating home galaxy.
