時差N小時:為何月球上沒有餐廳(上)

　　Why are there no restaurants on the moon? Greatfood. No atmosphere. The atmosphere is the layer ofgases that surrounds a planet or other massivebody. Although our atmosphere extends for tens ofmiles, almost ninety-nine percent of it is withineighteen miles of the earth's surface. Our ownatmosphere is mostly nitrogen, with about twenty-percent being the oxygen we breathe. But, a planetdoesn't start out having an atmosphere like ours.Much of the carbon dioxide that envelops earth, forexample, was originally embedded inside rocks, andlater released by heat from the sun. About a billion years ago, simple green plants startedgenerating oxygen, which soon became a major part of our atmosphere as well.

　　為何會月球上沒有餐廳?很棒的食物。沒有大氣層。大氣層是環(huán)繞星球或其他巨大天體的大氣層。雖然我們的大氣層延伸幾十里，幾乎99%的大氣都在地球表面18英里范圍內。我們自己的大氣層主要成分是氮，約20%的成為我們呼吸的氧氣。但是，一個星球最初時的大氣層和我們的大氣層并不一樣。很多二氧化碳籠罩大地，比如，原本儲存在巖石內的二氧化碳，經(jīng)過太陽的加熱而被釋放出來。大約10億年前，簡單的綠色植物開始產(chǎn)生氧氣，氧氣很快成為了我們的大氣層主要部分。