有记载的人类历史仅跨越了大约五千年。

原文英文

Humanity is a state of being on Earth during a specific period under certain natural conditions, while Earth itself is a state of the universe during a specific period under certain cosmic conditions. By extension, humanity’s place in the universe is also a state of the universe under specific temporal and environmental circumstances. This leads to the question: Do aliens exist? Have other species evolved on other planets? Lacking scientific evidence, this is an extremely difficult question to answer. Extraterrestrial life may or may not exist; if it does, it might not be in our current spacetime, or it may be in the same spacetime but too far away to be perceived.

Let us delve deeper into this topic. Earth has gone through several stages, but no one can fully elucidate its evolutionary process. One prevailing theory suggests that Earth was born from the Big Bang. Subsequently, Earth's environment evolved, eventually becoming suitable for the proliferation of life. Earth's environment can be categorized into two types: the natural environment, which can be altered by human activities, and the cosmic environment, which is beyond human control and changes with the material fluctuations of the universe. For spacetime, brief cosmic changes may represent vast spans of time for humanity. Consequently, the subtle shifts of Earth within the universe's dynamics often go unnoticed. The period of human existence is merely a minuscule fragment of Earth's history of life. Recorded human history spans only about 5,000 years, and modern civilization has developed for just 200 years. Compared to Earth's long evolutionary history, this is infinitesimally small.