Every time you had one more proton, you had another element.
每发现多一个质子，就会多一种元素。
2
Only then can they hope to describe conditions at the Big Bang, when all space and time was compressed into a volume far smaller than a proton.
只有那样他们才能指望描述大爆炸的情况，所有的空间和时间全部在那时被压缩成一个远小于质子的体积。
3
Heavy water is heavy because the hydrogen in it weighs twice as much as ordinary hydrogen (it has a proton and a neutron in its nucleus, instead of just a proton).