氦是钍和铀元素数千年放射性衰变的副产品。
Helium is the by product of millennia of radioactive decay from the elements thorium and uranium.
这颗晕星不同于大多数超新星，它吐出的许多元素比铁还重，其中包括放射性钍和铀。
Unlike most supernovae, this one spewed lots of elements far heavier than iron, including radioactive thorium and uranium.
稀土矿山常常也含有放射性元素，比如铀和钍。
Rare earth mines often also contain radioactive elements, such as uranium and thorium.
应用推荐