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TED-Ed演讲:地球的年事有多大(01)

宣布工夫:2018-04-15内容泉源:VOA英语学习网

How old is the Earth?

地球的年事有多大?

Well, by counting the number of isotopes in a sample of rock that's undergone radioactive decay, geologists have estimated the Earth's birthday, when it first formed from a solar nebula, to be 4.6 billion years ago.

经过对岩石样品中正派历着放射衰变的同位素计数,地质学家们曾经预算出了地球的生日,它从太阳星云中降生约莫是在46亿年之前。

But just how long is that really?

但是那究竟是多久呢?

Here's some analogies that might help you understand.

这里有几个类比应该会协助我们了解。

For example, let's imagine the entire history of Earth until the present day as a single calendar year.

比方,我们把地球到如今的整个汗青想象成一个日积年。

On January 1st, the Earth begins to form.

在1月1号的时分,地球降生了。

By March 3rd, there's the first evidence of single-celled bacteria.

到了3月3号,开端有证据证明单细胞细菌的呈现。

Life remains amazingly unicellular until November 11th when the first multicellular organisms, known as the Ediacaran fauna, come along.

直到10月11号之前,生物仍惊人地坚持着单细胞的形态,这时第一种多细胞生物也便是埃迪卡拉植物群呈现了。

Shortly thereafter, on November 16th at 6:08 p. m. is the Cambrian Explosion of life, a major milestone, when all of the modern phyla started to appear.

不久之后的11月16号下战书6点08分,寒武纪生命大迸发,它是一个紧张的里程碑,古代生物门类开端呈现。

On December 10th at 1:26 p. m. , the dinosaurs first evolve but are wiped out by an asteroid just two weeks later.

12月10号下战书1点26分,恐龙起首开展起来,但仅仅在两周后就被一个小行星彻底抹去。

On December 31st, the mighty Roman empire rises and falls in just under four seconds.

12月31号,强势的罗马帝国崛起又衰落,仅仅用了4秒钟。

And Columbus sets sail for what he thinks is India at three seconds to midnight.

哥伦布在他以为是印度三秒到半夜的时分扬帆起航。

If you try to write the history of the Earth using just one page per year, your book would be 145 miles thick, more than half the distance to the international space station.

假如你想要把地球汗青写上去,且一页纸即是一年,那么这本书将会有145英里(约233公里)那么厚,比我们到国际空间站的一半间隔还远。

The story of the 3.2 million year-old Australopithecine fossil known as Lucy would be found on the 144th mile, just over 500 feet from the end of the book.

320万岁北方古猿化石露西的故事将在第144英里处被找到,仅仅另有500英尺便到了书的开头。

来自:千亿国际文娱网页版_千亿国际文娱|www.qy449.com 文章地点: http://www.tingvoa.com/html/20180415/550477.html