时差N小时:为何月球上没有餐厅(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.

　　除了这些自然进程产生氧气外。您还需要重力。没有足够的引力，任何气体都会泄漏到太空，并消失。地球也这样失去了一些大气，但总体来说地球吸引住足够多的大气。月球，从另一方面说，它只有地球的六分之一的引力，无法完成这样的工作。尽管如此，最近的观测表明，月球确实有其自身的大气层。但它是如此之薄，它只能作为一个技术术语计数，而不能被互信。谈到月球上的餐厅就说这么多。