These are also the telltales in distant layers of ejecta that the rock in question has come from an impact.

在年代久远的喷发物地层中有迹象表明此处的岩石产生于一次撞击。

The telltales are specific "lines" in the spectrum of infra-red light from the plume. These correspond to the frequencies of light given off when water molecules are energetically excited.

表明这一迹象的是撞击掀起的尘土中显示的红外线光谱中的一些谱线，其频率与水分子能量激发时所发出光线的频率相应。