known to us, in the universe.

在宇宙中，地球是萬物的家

Its age is about 1/3 of the age of the universe

地球年齡大約是宇宙的三分之一

and, admitted,

而且無可否認的是

It is a thing of beauty.

地球的存在就是美麗

a slightly squashed fair with a heavy metal core,

受到稍微均勻擠壓的地心，充斥著重金屬

and a lighter surface crust,

以及較輕的地殼表面

wrapped in a thin sliver of sweet air to breathe,

以一層薄薄的甜美空氣包覆著呼吸

with vast oceans,

還有無邊際的海洋

fertile plains,

肥沃的平原

magnificent mountains,

壯闊的高山

fresh water rivers, streams, lakes and aquifers,

清澈的淡水河流、小溪、湖泊、地下水

orbiting a star which warms us,

環繞著一顆提供我們溫暖的恆星

and gives us energy.

並給予我們能量

But how did our home come in to existence,

但是到底我們的家鄉地球是怎麼出現的呢？

and what's it made of?

又是什麼組成的呢？

4.6 billion years ago,

46億年前

Earth was created from the remnants of dead stars,

地球從死亡恆星的星雲中孕育而生

that collected in a giant, dirty gas cloud.

聚集成一團巨大且骯髒的氣體雲

The gas cloud became denser in its center,

氣體雲的中心內部變得越來越高密度

and formed an accretion disk.

並形成一個吸積盤

small particles started clumping together,

小型粒子開始撞擊在一起

and building larger and larger objects,

並形成越來越大的物體

until they form the objects we call "Planets" today.

進而形成一個我們今天所謂的「星球」

This process took 10 to 20 million years,

這個過程歷時十年到兩千萬年的時間

and is still not very well understood.

而且我們對此還不是很了解

At about this time, when the solar system was young and chaotic,

差不多在那時候，太陽系還是相當年輕且混亂

a giant object, about as big as Mars,

一個巨大的物體，大概和火星一樣大

collided with our home.

撞擊了我們的家鄉地球

The impact was violent,

此撞擊威力非常強大

and if the object had been more massive,

而且如果當時的那個物體再大一點的話

it might have destroyed Earth.

地球可能就會被毀滅

Materials from Earth were smashed out into orbit,

撞擊出來的地球物質在特定軌道上運行

and formed the Moon,

進而形成月球

which is the biggest satellite in relation to its planet in the solar system.

月球是太陽系中最大的衛星

At this time, Earth was a hot hell,

當時的地球還是個炙熱的煉獄

constantly being hit by asteroids,

不斷的遭到小行星撞擊

with seas of lava,

有著熔岩海洋

and a toxic atmosphere.

以及劇毒大氣

But something was about to change drastically.

但是事情卻開始有急遽的轉變

Earth cooled down.

地球逐漸冷卻

Water from the inside of the Earth

從地球內部冒出水來

wandered to the surface and rained down on Earth,

佈滿地表，也開始降雨

only to vaporize again and become clouds.

水又蒸發成為天上的雲

Millions of asteroids brought more and more water to our planet.

數百萬的小行星帶給地球越來越多的水

All the water on Earth has about this volume compared to Earth.

地球上所有的水相較於地球體積大概是這樣

Today,

今日

the surface of Earth is 71% water,

地球表面有百分之71是水

and 29% land.

以及百分之29的陸地

97.5% is saline water,

其中百分之97.5都是鹹水

while only 2.5% is fresh water.

只有百分之2.5是淡水

The Fresh water is 69% ice and snow,

百分之69的淡水都是冰或雪

30% are ground waters,

百分之30是地下水

and only about 1% make up the remaining ground waters.

而只有大約百分之1是地表的水

But even this small part is mostly frozen.

但是雖然在這一小部分裡面大部分都是冰凍的水

Only a tiny part of our water is actually lakes and rivers.

我們的水裡面只有一小部分是湖泊或河流

and an even tinier part is bound in living things.

而那微小的一部分卻與萬物生存息息相關

So, gradually the Earth cooled down,

所以，當地球漸漸冷卻

and the surface formed a thin crust.

表面形成了一層薄薄的地殼

But inside the earth, hot rock continue to swirl about,

但在地球內部，熾熱的岩石依然在對流

moving the crust from below and breaking it apart.

在地殼下流動並將地殼分成數塊

This process is called "Plate Tectonics",

這個過程就叫做「板塊運動」

and is happening right now.

至今依然正在進行中

We'll make a whole video about it in the future.

我們會再針對這個主題製作一個影片

For now,

目前

let's just say that the crust of Earth consisted of

我們只能說地球的地殼是由數塊

separate giant plates that move around.

會移動的巨大分離板塊組成

As they meet, they crumble, and create mighty mountains.

當板塊相撞時，它們會擠壓並形成高聳的山

OR:

或是

violently plunge back down, deeper into Earth,

猛烈的擠回地球內部、深入地心

creating deep trenches.

形成深邃的海溝

That's the way the highest place on Earth was formed: Mt.Everest,

藉由這樣的過程，地球最高點：珠穆朗瑪峰形成

and the deepest: the Mariana Trench.

以及最深處：馬里亞納海溝形成

From our perspective,

從我們的觀點來看

Earth's mountains and trenches are mighty indeed,

地球上的高山或是海溝都很壯觀

but when you look at the Earth in cross-section,

但是如果從地球的剖面來看

you can see how tiny they actually are.

你就會發現其實它們相當的渺小

The part we stand on is the crust,

我們站著的地方是地殼

which is about 50 kilometers thick,

大約是50公里的厚度

though it can vary between 5 and 70 kilometers

雖然厚度可能從5公里到70公里都有可能

By the way,

順便提一下

the deepest hole ever drilled by man

人類史上鑽的最深的洞

is 12.262 kilometers deep.

只有 12.262 公里深

After the crust, comes the mantle.

地殼之下就是地函

It's a silicate rocky shell,

是一層矽酸鹽岩石外殼

and about 2,900 kilometers thick.

大概是2900公里的厚度

The mantle consists of the upper mantle, and the lower mantle.

地函分為上部地函及下部地函

The upper mantle has different regions, too.

上部地函也分為不同的部分

It's upper part, which is viscous and carries the crust,

上部地函具有高度黏性並可以帶動地殼

is called the "Lithosphere."

稱為「岩石圈」

After that, there comes the "Asthenosphere,"

在這之後是「軟流圈」

which consists of less mobile, mostly solid material.

主要是由不太流動的固體材料所組成

The lower mantle reaches deep down to the outer core of Earth.

下部地函延伸到地球的外核

Earth's outer core is a liquid layer of iron and nickel,

地球外殼是鐵和鎳的液體層

about 2,266 kilometers thick.

厚度約是2266公里

Temperatures vary from 4,000℃(7,232℉)

溫度變化從攝氏4000度（華氏7232度）

to 5,700℃(10,292℉).

到攝氏5700度（華氏10292度）

And in the center, is the inner core.

而在中心的就是內核

It's mostly solid,

大部分都是固體

a ball made of an iron-nickel alloy.

由鐵鎳合金所形成的球體

with a radius of about 1,200 kilometers.

半徑約1200公里

70% of the size of the moon,

是月亮體積的百分之70

and about the temperature of the surface of the Sun.

溫度則大概跟太陽表面溫度一樣

It is slowly growing

而且還會慢慢成長

at an estimated rate of about 1mm/year.

估計的速度大概是每年1公厘

Now, for some respective,

現在，我們來比較看看

this small layer of crystallized melt products of former molten mantle,

這一小層是由地函溶解結晶的產物所形成

is where we live.

就是我們居住的地方

Then, there's Earth's magnetic field.

然後，我們來看看地球的磁場

It's an invisible phenomenon

這是一種看不見的現象

that diverts high energy particles coming from the Sun and other sources,

能夠阻擋來自地球或其他地方的高能量粒子

allowing for a stable environment

以穩定地球環境

with comparatively little radiation impact on Earth.

相對減少地球所受到的輻射影響

But why is it there?

但是為什麼有磁場呢？

Actually, we don't really know a terrible lot about that.

其實，我們並沒有很了解磁場

We know, it has something to do with the core of Earth.

我們知道這個和地球有一定的關係

Inside this metal sphere,

在這個金屬球體裡面

large electrical currents flow in complicated patterns.

大型電流以複雜的形式流動

They cause a magnetic field,

進而引起磁場

that sort of stabilizes itself according to the laws of electrodynamics.

並根據電動力學的定律來穩定此磁場

This entire system is called the "Dynamo."

這整個系統就稱為「地球潮磁（發電機原理）」

But, don't let us fool you into thinking we have it all figured out.

但是，不要被我們騙了，以為我們已經全然了解磁場的一切

Speaking of breathtaking information,

我們來談談其他驚人的事情

what about the airy stuff that surrounds us?

在我們周遭的氣體又什麼東西呢？

By volume,

從體積來看

dry air consists mostly of Nitrogen,

乾空氣大部分都是氮

Oxygen,

氧

Argon,

氬

Carbon,

碳

a variable amount of water vapor,

以及含量不穩定的水蒸氣

and small amounts of other gases.

還有一些少量的其他氣體

Humans are very dependent on the lowest layer of the atmosphere:

大氣層最底層的部分對人類來說很重要

the Troposphere - Where the weather is.

也就是對流層，天氣現象都是在這一層內出現

It's 12 kilometers thick on average.

平均厚度是12公里

Above that is the Stratosphere,

再往上就是平流層

which is where the ozone layer protects us

此層能夠抵擋太陽射線中

from the sun's most aggressive type of light.

最危險的紫外線，也就是臭氧層的位置

Above that is the Mesosphere - the coolest place on Earth,

在往上一層就是中氣層，是地球上最寒冷的地方

with an average temperature around -85℃(-121℉).

平均溫度大約在攝氏－85度（華氏－121度）

At about 80 kilometers up, the Thermosphere starts.

再往上80公里就是增溫層

The transition to space is a fluent one, without clear borders.

這些層之間的分界都是連續的，並沒有清楚的界線

but humans decided that space starts here.

是人類決定從這裡開始就是太空

At about 100 kilometers, Earth stops, and space begins,

在大約100公里處，地球的部分就結束了，接下來就是太空

though the atmosphere extends a bit further.

雖然大氣層還延伸的再遠一點

In this region, we find the Ionosphere,

在這區域內，我們發現了電離層

the aurora borealis,

北極光

and the ISS,

以及國際太空站

and the outermost layer is the Exosphere,

最外層就叫做外大氣層

stretching up to 10,000 kilometers.

可以向上延伸一萬公里

It merges fluently with outer space,

與外太空慢慢的接壤

where there's no atmosphere at all.

在那，就沒有任何的大氣

The atoms and molecules in this area are so far apart,

在這區裡面的原子和分子距離非常的遠

that they can travel hundreds of kilometers

它們可以移動行經數百公里之遠

without colliding with each other.

而且都不會互相撞擊

OK.

OK

Humans, in their present form,

現在的這種人類

have only been around for 200,000 years.

只大概出現在地球20萬年

- that's 0.004% of Earth's history.

僅僅是地球歷史的百分之0.004

Not long, really.

真的一點都不長

And, here we are now,

而我們現在生存在

living in a thin, moist layer on a small, wet rock.

一層又薄又濕潤的岩石

We call this rock: Earth.

我們把這個岩石叫做地球

It is the product of the universe's deepest workings,

地球是宇宙最匠心獨具所創造出來的產物

the result of a constant process of creation and destruction,

經過不停地創造以及毀滅的過程才得以出現

happening all of the universe, all the time,

發生在宇宙的每一個角落、每一秒

helped by chance,

有時候有幸運的協助

the laws of the universe and random events,

遵守著宇宙與隨機事件的定律

we are really lucky.

我們真的是非常的幸運