評(píng)論
打印
Open the window and let some fresh air down.Ok!
打開窗戶讓新鮮空氣進(jìn)來(lái)。好的。
Take a deep breath of oxygen.
啊！深吸一口氧氣。
It might not always been there,you know.
你知道的，它不是一直都有的。
What do you mean?
什么意思？
According to climate researcher James Kasting, when the earth first formed there might not have beenany oxygen around.
氣候研究員的 James Kasting指出當(dāng)?shù)厍虺跏夹纬蓵r(shí)，周圍并沒有氧氣。
Before the begining of the life？
在生命開始之前嗎？
No,there would have been life, just no oxygen.
不，有生命，只是沒有氧氣。
For example, take methanogens, the microbes that make methane.
比如產(chǎn)烷生物，一種制造甲烷的微生物。
They only thrive when there's no oxygen around.
它們只在周圍沒有氧氣的時(shí)候才能生存。
Is that why they live in airless places like the stomachs of cows?
這就是它們?yōu)槭裁瓷钤谙衽Ｎ改菢硬煌L(fēng)的地方的原因嗎？
Correct!And according to the theory, back when the earth was young and there was no oxygen around, methanogens ruled and the atmosphere was filled with methane.
正確。根據(jù)理論，當(dāng)?shù)厍蚰贻p并且沒有氧氣的時(shí)候，產(chǎn)烷生物統(tǒng)治著地球，空氣里面充滿了甲烷。
So when did Oxygen come on the scene?
那么氧氣是什么時(shí)候出現(xiàn)的呢？
Not untill about a billion years later.
直到大約十億年后。
But without methane, oxygen-producing microbes might not haveevolved as quickly as they did.
但是如果沒有甲烷，制氧微生物就不會(huì)進(jìn)化的如此之快。
See, methane is a powerful greenhouse gas, meaning that it could havehelped keep the sun's rays trapped near the earth's surface.
甲烷是一種強(qiáng)有力的溫室氣體，它可以維持地球表面的太陽(yáng)光線。
This was important, since billions of yearsago the sun was weaker than it is today.
這是非常重要的。因?yàn)閹资畠|年前太陽(yáng)的光線比現(xiàn)在弱。
So without the methane-induced greenhouse effect, the earth might have frozen solid until the sun got hotter.
因此如果沒有甲烷制造的溫室效應(yīng)，地球可能會(huì)被凍成一個(gè)堅(jiān)硬的固體，直到陽(yáng)光變強(qiáng)為止。
But when the earth would have become way too hot?
但是地球變得太熱了怎么辦呢？
Yes. If not for the fact that the methane rich atmosphere also could have helped to reflect enough incoming sunlight to maintain a delicate temperature balance.
是的。甲烷豐富的大氣同樣有助于折射足夠多的射入陽(yáng)光，使溫度保持一種微妙的平衡。
So maybe the earth stayed warm, but not too warm, until oxygen-producing microbes evolved andfilled the atmosphere with oxygen, which drove away most of the methane.
所以地球保持著溫暖，但不至于太溫暖。直到制氧生物進(jìn)化完成，趕走了絕大多數(shù)的甲烷，讓大氣充滿氧氣。
Right.
是的。
Well!You've just made my breath of fresh air more interesting.
嗯，你讓我呼吸新鮮空氣變得更有趣了。
