On the vast cosmic stage, the Milky Way galaxy is like a mystery waiting to be uncovered, inspiring mankind to explore the infinite reverie of the existence of extraterrestrial civilizations. Mankind's desire to explore the unknown, especially other civilizations that may exist in the galaxy, has been an important chapter in scientific exploration since ancient times.

In order to unravel this cosmic mystery, scientists have devoted themselves to many years, using various cutting-edge technologies and methods, trying to capture clues about the existence of extraterrestrial civilizations. Among them, astrophysicists Tom Westby and Christopher W. J. Concelis, based on the history of the formation of the Earth and the environmental conditions, set a series of assumptions for the formation of extraterrestrial civilizations.

他們指出，外星文明所依賴的恆星年齡需超過50億年，且這些文明可能孕育在類似地球的岩質行星上，這些行星必須位於恆星的宜居帶，並且該恆星系統還需擁有豐富的重元素。基於這些條件，他們對銀河系內各類因素進行了詳盡分析，最終估算出銀河系中可能存在多達36個與地球文明相似、具備無線電通訊能力的外星文明。

然而，這一觀點僅是眾多推測中的一種。在科學界，關於銀河系文明數量的估計可謂五花八門。有科學家甚至大膽預測，銀河系中可能存在多達10萬個文明，儘管這一說法目前仍缺乏確鑿證據支援。

為了更精確地估算銀河系文明的數量，研究人員藉助天體物理學原理和數據分析方法，深入剖析了地球形成與銀河系恆星總數的關係、年齡超過50億年的恆星比例、擁有適宜行星系統的恆星比例、金屬豐富的恆星比例以及可交流文明的平均壽命等多重因素。

The researchers also used data analysis techniques to study the age distribution of stars in the Milky Way in detail. They screened out stars that were older than a certain criterion and analyzed the number of stable, moderately dense planets around these stars, and further estimated key indicators such as the number of planets in the habitable zone and the metal content of terrestrial planets.

然而，人類在探索銀河系文明的過程中，面臨著前所未有的巨大挑戰。首先，天文距離成為橫亙在探索路上的巨大障礙。銀河系的直徑長達約10萬光年，這一廣闊的空間使得人類的探索變得極為艱難。即便以接近光速的速度前行，想要遍歷整個銀河系也需耗費難以估量的時間和資源。

The secrecy of extraterrestrial civilizations also makes human exploration difficult. In the vastness of the universe, there may be some advanced civilizations that choose to remain silent to the outside world, like observers hidden in the shadows. They may choose not to reveal their existence out of their own safety, technical considerations, or disdain for human technology. This phenomenon is vividly known as the "observer effect", and it makes the search for extraterrestrial civilizations feel like groping in the dark.

To complicate matters further, there are limitations to our definition of intelligent life. We often think of carbon-based life as a standard, ignoring the possible existence of life forms based on silicon or other elements. The limitations of this knowledge limit our understanding of other possible life forms, making it difficult for existing astronomical methods to detect them. At the same time, our detection technology needs to be further improved to deal with the possible life forms in the universe that are beyond our scientific understanding.

Despite the many difficulties and challenges, humanity's enthusiasm for exploring galactic civilization has never waned. With the continuous progress of science and technology, it is expected that major breakthroughs will be made in astronomical observation equipment and detection technology in the future. The development of new telescopes will greatly improve the accuracy and range of observations, allowing us to capture fainter cosmic signals and thus gain a deeper understanding of the mysteries of the universe. At the same time, the application of artificial intelligence and big data technology will also make the processing and analysis of observational data more efficient, and further improve our understanding of the universe.