求翻译：人类已经在地球上生活了大约两三百万年。从前，人类以为自己是万物之灵，宇宙间唯一有智慧的生命，甚至认为地球是整个宇宙的中心。后来，随着科学技术的进步，人们的眼界开阔了，才懂得宇宙的广大无边，它远远超越了我们的想象，而地球实在是太小了，当然更不是宇宙的中心。于是人们想象：宇宙这样宽阔，或许其它星球上会生活着一种与人类相似的智慧生物--外星人。这样的想法深深地吸引了一些热哀于寻找外星人的人们。是什么意思？

Humans have lived on Earth for about two or three million years. Once upon a time, mankind thought he is the soul, the only intelligent life in the universe, or even that the earth was the center of the universe as a whole. Later, with the scientific and technological progress, people's horizons bro

Human life on earth by about 23 million years. Once upon a time, human thought of themselves as 10,000 between the creatures, and the universe Only wisdom of life as a whole, and even of the view that the earth is the center of the universe. Subsequently, along with advances in science and technolog

Humans have been living on Earth for approximately 2 million or 3 million years. Once upon a time, humans think they are as optimal soul, the only intelligent life in the universe, even thought the Earth was the center of the universe as a whole. Later, with the pr