它爆炸的威力相当于一百万枚核弹，释放出太阳的能量。

　　It set alight the entire biomass of earth and cooked the atmosphere.

　　它点燃了地球上全部的生物量，烘烤着大气层。

　　What was once a vibrant planet became a wasteland where billions of life forms were vaporized and turned into ash.

　　原本活力十足的星球变成了一片荒原，数十亿生命被蒸发变成了灰烬。

　　The final days, hours and minutes of the dinosaurs.

　　这就是恐龙的最后时刻。

　　Our planet's first mass extinction.

　　我们星球上的首次大灭绝。

　　They were the Earth's largest animals.

　　它们曾是地球上最大的动物。

　　New technology and forensic evidence helps paleontologists bring to life some of their final moments.

　　新的科技和现场证据如今帮助古生物学家们重现了它们生命中的最后时刻。

　　Four and a half billion years ago. The first life forms appeared.

　　四十五亿年前。最早的生命形式出现了。

　　They've engaged in a battle for survival ever since, combating new predators, and environmental catastrophes.

　　从那时开始，它们就为了生存不断地斗争着，对抗新的掠食者和环境性的灾难。

　　While many were able to adapt, most species failed and were lost from existence.

　　很多物种能够适应的同时，多数物种失败了最终在灭绝中湮没。

　　Planet earth has faced 5 such extinctions.

　　行星地球面临过五次这样的灭绝。

　　When we look at the history of life, we see that there are many, many extinction events throughout the last four and a half billion years, that is, throughout the history of the earth.

　　当我们在回顾生命的历史时，我们发现在过去的四十五亿年里，即在地球历史上，有过很多很多灭绝事件。

　　The one with the dinosaurs, 65 and a half million years ago was a big extinction, but that wasn't even the biggest.

　　在六千五百万年前恐龙的灭绝是一次大灭绝，不过它并非最大的一次。

　　There have been many that have been far worse.

　　有过多次比这严重得多的大灭绝。

　　Every once in a while, there's some really, really major events, what we call mass extinctions, where we lose lots of different species of many different ecological types.

　　每隔一段时间，就会有一些这样真正的大事件，我们称作大规模灭绝，地球失去过许多不同生态类型里的很多不同物种。

　　Plants, animals, predators, herbivores, sea animals, land animals.

　　植物、动物、掠食者、植食动物、海洋动物、陆生动物。

　　Extinction is the normal outcome of evolution.

　　灭绝是进化的正常结果。

　　The fact of the matter is over 99% of all the organisms that have ever lived are extinct.

　　实际上情况是所有曾经生活过的生物中，百分之九十九以上都已经灭绝。

　　So it isn't unusual to become extinct, it's actually normal.

　　所以走向灭绝没什么不寻常的，这是正常情况。

　　But there are certain periods in which there's more extinction than usual.

　　不过有些特定时期会有比比平常更多的灭绝现象。

　　We call these mass extinctions.

　　我们称之为大灭绝。

　　Mass extinctions is gonna cover over an extended period, or they can happen in the blink of an eye.

　　大灭绝可能会持续一段时间也可能在眨眼间发生。

　　These mass extinction events can be seen in the fossil record.

　　这些大灭绝事件能从化石记录中看出来。

　　You'll find the fossil remains of thousands of life forms in one layer of dirt, and then none of those same plants and animals in the layer directly above.

　　你可能会在一层泥土中发现数以千计生物化石遗骸，然后在上面的土层中却没有任何同样的植物和动物。

　　So what that tells us, is something caused a lot of things to die between this time and that.

　　所以这告诉我们的是，有事件导致很多生物在这一时期和那一时期之间死亡。

　　Sometimes the distance between those layers of rocks can represent millions of years, and other times they can be months, weeks or even days.

　　有些时候这些石头层之间的距离可能代表数百万年，有些时候可能只是几个月、几周甚至几天。

　　250 million years ago, one group of beasts would rise above all others and claim the world as their own.

　　两亿五千万年前，一类动物从各种动物中脱颖而出获得了在地球的统治地位。

　　It was the Mesozoic era, when dinosaurs reigned supreme.

　　那是在中生代时期，恐龙称霸。

　　Before they were ultimately wiped out, they would evolve to become the fastest, cleverest, most successful animals on earth.

　　在它们全部消亡之前，它们进化成地球上最快、最聪明、最成功的动物。

　　There are two reasons why dinosaurs took over the planet.

　　恐龙能够统治地球有两个原因。

　　The first was their larger than average brains.

　　第一个是它们比平均水平更大的大脑。

　　Now compared to you and I, they are not that smart, but in their time, they were the most intelligent creatures on earth.

　　现在与你我相比它们没那么聪明，不过在那一时期它们是地球上最聪明的动物。

　　But the main reason why they were so successful was because of the design of their hips and legs.

　　不过它们能够如此成功的主要原因是它们髋部和腿部的构造。

　　The reptiles and mammals of their time had legs that stuck out to the side of their body.

　　那一时期的爬行动物和哺乳动物腿是从身体侧面伸出来的。

　　This meant that running was a bit more difficult because the entire body waddles from side to side.

　　这就意味着跑动会有些困难，因为整个身体都在左右摆动。

　　But the dinosaurs carried their legs directly beneath their body, like we do.

　　不过恐龙和我们一样腿部就在身体的正下方。

　　And this meant that they could run much faster and a lot more efficiently than anything else.

　　这说明它们能比其它任何动物都跑得更快也更高效。

　　So being faster and having the ability to run longer is what gave them a competitive edge that no other creatures could match.

　　能够跑得更快并且跑得更远，给了它们其它生物无可比拟的竞争优势。