Extraterrestrial Civilizations (1979)

随笔科学文献

作者: 艾萨克·阿西莫夫
首版: 1979 年
国家/地区: 美国
Open Library: 11 个版本

百科

这个词条暂时没有中文维基百科条目，下面是英文维基百科的内容（英文原文）：

Extraterrestrial Civilizations is a 1979 book by Isaac Asimov, in which the author estimates the probability of there being intelligent extraterrestrial civilizations within the Milky Way galaxy. This estimation is approached by progressively analyzing the requirements for life to exist.

Overview

The term "Earth-like world" is prominent, in that the assumption is made that any world where life could evolve would have certain similarities to Earth, such as temperature ranges and gravity sufficient for an atmosphere to exist. Asimov begins with the estimated number of stars in the galaxy, 300 billion.

This number is then reduced to 280 billion as stars without planetary systems are discarded, and then furthermore reduced as more factors are taken into consideration. This process culminates in the statement that "the number of planets in our galaxy on which a technological civilization is now in being is roughly 530,000."

以上文字摘自英文维基百科「Extraterrestrial Civilizations」（去掉了参考文献等尾部小节），按 CC BY-SA 4.0 使用，作者为维基百科的各位编者。