Another source is elements like uranium deep inside the Earth, which add heat as the atoms radioactively decay.

另一个来源是地球深处的铀等元素，它们通过原子放射性衰变增加热量。

And for the most part, nowadays, they are discovering this fact retroactively, so only after the element has already decayed radioactively into something else.

在大多数情况下，如今，他们是追溯地发现这个事实，所以只有在元素已经放射性衰变成其他东西之后。

They do a calculation in Los Alamos during the war or just after it, about how many of those you need to set off to make the atmosphere radioactively uninhabitable.

在二战期间或刚结束时，他们在洛斯阿拉莫斯实验室做了计算，算出需要引爆多少颗超级炸弹，才能让空气在辐射影响下不宜居住。

Uranium atoms are similar enough to zirconium that they can occasionally slip into the mineral's crystal lattice in zirconium's place when the mineral is forming, but unlike zirconium, the unstable uranium atoms eventually radioactively decay into lead atoms.

铀原子与锆相似，以至于在矿物形成时，偶尔可以滑入矿物的晶格中代替锆，但与锆不同，不稳定的铀原子最终会放射性地衰变成铅原子。

They don't wanna mess this up, because once you put the plutonium in there, every little step of getting it closer to being a bomb makes it a little bit more dangerous to be around and radioactively, you know, problematic.

他们不想把事情搞砸，因为一旦你把钚放进去，让它更接近炸弹的每一小步都会让周围的辐射变得更危险，你知道，这是个问题。