The most devastating asteroid to hit Earth - Sean P. S. Gulick

翻译人员: Alex Gish 校对人员: suya f.

66 million years ago, near what’s now the Yucatán Peninsula,

6600万年前，在现在 的尤卡坦半岛附近，

a juvenile sauropod feasted on horsetail plants on a riverbank.

一只幼蜥脚类动物在河岸 上以马尾植物为食。

Earth was a tropical planet.

地球是一颗热带行星。

Behemoth and tiny dinosaurs alike roamed its lands,

巨兽和小恐龙都在它的陆地上漫游，

while reptiles and tentacled ammonites swept its seas.

而爬行动物和触手的氨化物 则席卷了它的海洋。

But, in an instant, everything would change.

但是，瞬间， 一切都会改变。

A roughly 12-kilometer-wide asteroid was careening toward Earth

一颗宽约12千米的小行星

at around 20 kilometers per second.

正以每秒约20千米的速度冲向地球

From where the sauropod stood,

从蜥脚类动物所在的地方来看，

there would have been no early warning signs.

不会有预警信号。

The asteroid barreled through Earth's atmosphere in a matter of seconds

这颗小行星在短短几秒钟内

and struck the Yucatán’s submerged continental shelf.

冲过地球大气层，击中了 尤卡坦州淹没的大陆架。

It exploded upon impact,

它在撞击时爆炸，

instantaneously creating a 100-kilometer-wide hole

瞬间形成了一个100公里宽 的洞，喷出沉积岩

and ejecting sedimentary and crystalline rocks.

和结晶岩。

Within minutes, the impact crater, known today as Chicxulub,

几分钟之内，今天 被称为Chicxulub

began collapsing inwards.

的撞击坑开始向内倒塌。

Meanwhile, the base rebounded some 20 kilometers above the Earth’s surface,

同时，基地在地球表面上方约 20公里处反弹，

then fell back down and moved outwards, creating a ring of mountains.

然后向下掉落并向外移动， 形成了一圈山脉。

The energy released from the asteroid’s impact is estimated to have been

据估计，这颗小行星撞击 所释放的能量是核弹的

several billion times that of a nuclear bomb.

数十亿倍。

The force sent seismic energy across the planet

这种力量

at a much greater magnitude than any earthquake

在地球 上发射的地震能量 比构造断层可能产生的任何地震

a tectonic fault could ever produce.

都要大得多。

Massive landslides ensued.

随之而来的是大规模的山体滑坡。

And a tsunami sped from the newly formed crater,

海啸从新形成的火山口加速出来，

potentially reaching 1,500 meters high.

可能达到1500米高。

Countless lives were extinguished.

无数生命被扑灭。

Some instantly: all life within 1,500 kilometers of the impact site

有些是立即：距离撞击地点 1500公里以内的所有生命都

was incinerated;

被焚烧了；

others right after: by colossal waves, landslides, and hurricane force winds.

另一些则紧随其后：被巨大的海浪、 山体滑坡和飓风强风焚烧。

But many organisms across the planet survived.

但是地球上有 许多生物幸存下来。

It was what came next that would bring about the end for many species,

接下来发生的事情将使

including almost all dinosaurs.

包括几乎所有恐龙在 内的许多物种走向终结。

This was just the beginning of one of the most devastating periods

这仅仅是地球生命史上最具破坏

in the history of life on Earth.

性的时期之一的开始。

When the asteroid struck, it sent hundreds of gigatons

当小行星撞击时，它向大气中 输送了数百亿吨富含二氧化碳

of carbon-dioxide-rich limestone and sulfur-saturated-sediments

的石灰石和富含硫的沉积物

into the atmosphere.

进入大气层。

The sulfur combined with water vapor to create sulfate aerosols.

硫磺与水蒸气 结合生成硫酸盐气溶胶。

This plume of limestone dust, soot, and sulfate aerosols

这股石灰尘、烟灰和硫酸盐气溶胶 以每秒几千米的速度从撞击现场

spread from the impact site at several kilometers per second,

扩散，在短短几个小时

blanketing the globe in a matter of hours.

内覆盖了地球。

It’s thought to have blocked the Sun,

人们认为它阻挡了太阳，

plunging Earth into an extended period of darkness

使地球陷入了漫长的黑暗

and dropping the temperature in many places by at least 25°C.

时期 ，使许多地方的温度 下降了至少25°C。

The asteroid’s immediate impact was devastating,

这颗小行星的直接 撞击是毁灭性的，

but it seems to have been the rapid climate change it triggered

但似乎正是它引发

that ended the roughly 165-million-year reign of the dinosaurs.

的快速气候变化结束了 恐龙长达1.65亿年的统治。

Plants and plankton rapidly died,

植物和浮游生物迅速死亡，

causing the collapse of food webs worldwide.

导致全球食物网崩溃。

An estimated 75% of life on Earth went extinct,

据估计，地球上有 75％的生命已经灭绝，

including almost all dinosaurs.

包括几乎所有的恐龙。

Small birds were the only kinds that remained,

小鸟是唯一剩下的种类，这

perhaps because they relied on hardy seeds that weathered the catastrophe.

可能是因为它们依赖耐寒 的种子来抵御灾难。

It's unclear why exactly the lifeforms that survived the extinction did.

目前尚不清楚为什么在灭绝中 幸存下来的生命形式确实如此。

Many smaller organisms, like insects, persisted.

许多较小的生物， 例如昆虫，仍然存在。

So did early mammals— perhaps because of their ability to burrow and hibernate.

早期的哺乳动物也是如此，这可能 是因为它们能够挖洞和冬眠。

And photosynthetic lifeforms like algae,

像藻类这样的光合生命形式也存活了下

that had ways of withstanding low-light conditions,

来，它们可以承受弱光条件，

also survived.

也幸存下来。

Traces of the asteroid scattered worldwide and the scar of the Chicxulub crater

散落在世界各地的小行星的痕迹 和奇克苏鲁布火山口的伤疤

attest to this period of monumental destruction.

证明了这段巨大的毁灭时期。

So, what are the chances of another Chicxulub happening?

那么，再次发生 Chicxulub 的可能性有多大？

Space programs are continuously identifying and tracking

空间计划正在不断 识别和跟踪

near-Earth asteroids.

近地小行星。

Fortunately, the likelihood of one as large and cataclysmic

幸运的是，在未来一千年左右 的时间里，发生如此大规模和灾难性的

striking in the next thousand or so years seems to be small—

袭击的可能性似乎 很小——大约是百万分

something like a 7 in a million chance.

之七的几率。

However, we are facing the consequences of another kind of rapid climate change,

但是，我们正面临另一种 快速气候变化的后果，

this time because of humanity's own emissions.

这次是因为人类 自身的排放。

Animals are going extinct faster than ever in our history,

在我们历史上，动物灭绝的速度 比以往任何时候都快，

and people are being displaced from their homes.

人们被迫背井离乡。

But, unlike the dinosaurs,

但是，与恐龙不同，

we have the opportunity to avoid the large-scale devastation that will come

我们有机会避免

if governments continue with the status quo.

政府继续 维持现状 所带来的大规模破坏。