氪在今天的大气层中比太阳能的氪更重一些，这些氪比埋入了陨星，也就是通常熟知的碳质球粒状陨石中的氪还有重很多。
Krypton in today's atmosphere is somewhat heavier than solar krypton, and the krypton embedded in meteorites known as carbonaceous chondrites is even heavier than that.
研究者通过研究球粒状陨石而得出太阳系的年龄。
It was the study of chondrites that allowed researchers to work out how old the solar system is.
他有两方面的证据：第一，现存的灾难性撞击的残骸与Baptistina和她的后代有相同的成分，这是必要条件，但并非充分条件，因为含碳的球粒状陨石在其它小行星上也有；
That is a necessary but not a sufficient condition, as the type of rock involved, called carbonaceous chondrite, is found in other asteroids, too.
应用推荐