地球的力量 第2集 大氣(3)對流層

We humans are perfectly adapted to survive atground level,

我們?nèi)祟愅耆m合在地表上生存

where the air has all the right conditions for life.

地表大氣的狀況正適合生命的存在

It's the right temperature, right pressure

合適的溫度，合適的氣壓

and it's got the right mix of gases.

合適的大氣的組成成分

Down here, there's plenty of oxygen about,

下邊這兒，有足夠的氧氣

but after about three kilometres the air's so thin,

但是大約三千米以后空氣會很稀薄

if you didn't have this mask, you'd slip into unconsciousness.

所以如果沒有這個防護(hù)面具，你會變的意識不清

I'd better put it on.

我最好還是戴上

121, continue your approach. Flight information...

一二一，起飛

The atmosphere that surrounds our planet

我們周圍的大氣

is made up of four key layers, each very different.

由四個主要的大氣層組成，每一個都不同

Although I'm above the clouds, I'm still at the very bottom,

盡管是在云彩上面，我仍然是在大氣層的底部

in a layer called the troposphere.

這個氣層叫做對流層

It's a narrow band,

它寬度很窄

usually more than six miles thick.

通常超過6英里的厚度

The troposphere is a rich soup of oxygen-rich air.

對流層是一個充滿暖濕氧氣的氣層

It's unstable, chaotic and unpredictable but life depends upon it.

它很不穩(wěn)定，空氣運動不規(guī)則而且不可預(yù)知，但是生命的存在取決于它

And in just a couple of minutes, I'll be leaving it behind.

只是在幾分鐘之后，它就會在我下面了

And now I'm 40,000 feet above the Earth.

我現(xiàn)在離地球有4萬英尺高