时间螺旋

时间螺旋

Time Spiral
Illustration Credit: Pablo Carlos Budassi via Wikipedia

Explanation: What’s happened since the universe started? The time spiral shown here features a few notable highlights. At the spiral’s center is the Big Bang, the place where time, as we know it, began about 13.8 billion years ago. Within a few billion years atoms formed, then stars formed from atoms, galaxies formed from stars and gas, our Sun formed, soon followed by our Earth, about 4.6 billion years ago. Life on Earth begins about 3.8 billion years ago, followed by cells, then photosynthesis within a billion years. About 1.7 billion years ago, multicellular life on Earth began to flourish. Fish began to swim about 500 million years ago, and mammals because walking on land about 200 million years ago. Humans first appeared only about 6 million years ago, and made the first cities only about 10,000 years ago. The time spiral illustrated stops there, but human spaceflight might be added, which started only 75 years ago, and useful artificial intelligence began to take hold within only the past few years.

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时间螺旋
图示提供: Pablo Carlos Budassi via Wikipedia

说明: 自宇宙创生以来发生过什么事？这张图所示的时间螺旋，呈现了其中的一些重要里程碑。螺旋的中心是大爆炸，也就是远在约138亿年前的时间起点。大爆炸后的数十亿之间，原子形成，接着原子形成恒星，然后恒星和气体再聚成星系；我们的太阳诞生，地球紧接着在大约46亿年前形成。地球上的生命大约起始于38亿年前；随着细胞的出现，光合作用在10亿年内发生。然后大约在17亿年前，多细胞生命开始繁衍。鱼类在大约5亿年前开始于大洋中游动，哺乳动物于大约2亿年前开始在陆地上行走。人类大约在600万年前出现，在1万年前左右建立了第一批城市。这个时间螺旋图示到此结束，但或许可再加上近在75年前开始的人类太空飞行，及近几年兴起、有实用性的人工智能。

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明日的图片: oyster stars