時(shí)差N小時(shí):為何月球上沒(méi)有餐廳(下)

　　But more than these kinds of natural processes areneeded to have an atmosphere. You also needgravity. Without sufficient gravity, any gases willjust leak out into space and be gone. Earth losessome of its atmosphere this way, but in general ithas enough mass to hold on. The moon, on theother hand, with only one-sixth the gravitationalpull of earth, isn't big enough to do the job. Still,recent observations have shown that the moon doesin fact have an atmosphere of its own. It's so thin,however, that it only counts as one in technicalterms, and certainly couldn't be breathed. So much for that restaurant.

　　除了這些自然進(jìn)程產(chǎn)生氧氣外。您還需要重力。沒(méi)有足夠的引力，任何氣體都會(huì)泄漏到太空，并消失。地球也這樣失去了一些大氣，但總體來(lái)說(shuō)地球吸引住足夠多的大氣。月球，從另一方面說(shuō)，它只有地球的六分之一的引力，無(wú)法完成這樣的工作。盡管如此，最近的觀測(cè)表明，月球確實(shí)有其自身的大氣層。但它是如此之薄，它只能作為一個(gè)技術(shù)術(shù)語(yǔ)計(jì)數(shù)，而不能被互信。談到月球上的餐廳就說(shuō)這么多。