Around 90% are protons, 9% are helium nuclei, and 1% are heavier nuclei.

约 90% 是质子， 9% 是氦核， 1% 是较重的原子核。

A helium nucleus is a tiny bit lighter than the combined mass of the 4 protons it is made from.

氦原子核虽然由四个质子形成但重量却比四个质子轻一点。

Protons and helium nuclei account for 99 percent of all cosmic rays, and analyzing the energy spectrum will provide key information for research.

质子和氦核占所有宇宙射线的99%，分析能量谱将为研究提供关键信息。

Scientists with the project say they have measured the energy spectrum of cosmic ray helium nuclei using four and half years of recorded data.

参与该项目的科学家表示，他们利用四年半的记录数据测量了宇宙射线氦核的能量谱。

This is actually a pretty complicated process with lots of steps, but in the end four protons plus some other ingredients get turned into one helium nucleus.

这实际上是一个非常复杂的过程，有很多步骤，但最终就是四个质子加上一些其他成分变成了一个氦原子核。

But then, after 380 millennia, it had cooled enough that electrons could combine with protons and helium nuclei, becoming stable neutral atoms for the very first time.

但是，在38万年之后，它已经足够冷却，电子可以与质子和氦原子核结合，第一次成为稳定的中性原子。

The helium nucleus obviously has a plus 2 charge, and the thorium atom would have a negative charge as well.

氦原子核显然带有正 2 电荷， 而钍原子也带有负电荷。

After an intricate game of particle jockeying, physicists have now measured the radius of the helium nucleus five times more precisely than before.

经过一场错综复杂的粒子争夺战后，物理学家现在测量到的氦核半径比以前精确了五倍。

This finding lines up nicely with the measurement of the helium nucleus derived through other means, though it's five times more precise.

这一发现与通过其他方式得出的氦核测量结果非常吻合，尽管它的精度要高出五倍。

The muon kicks out both the atom's electrons, and what's left is the helium nucleus—which is two protons and two neutrons—and a muon.

μ 子踢出原子的两个电子，剩下的是氦原子核——它有两个质子和两个中子——和一个μ 子。

This is called alpha decay and the particle that it emits is basically the same as a helium nucleus: two protons and two neutrons.

这称为 α 衰变，它发射的粒子与氦原子核基本相同：两个质子和两个中子。

Two atoms of hydrogen make one atom of helium, smash three helium nuclei together, you get carbon, add one more helium nucleus, you get oxygen, you get the idea.

两个氢原子形成一个氦原子，将三个氦原子核粉碎在一起，得到碳，再添加一个氦原子核，得到氧，你明白了。

The laser energy used to move the muon up to that unstable state can be used to calculate the radius of the helium nucleus, which is 1.67824 femtometers—one femtometer being one quadrillionth of a meter.

用于将 μ 子移动到不稳定状态的激光能量可用于计算氦原子核的半径，即 1.67824 飞米——一个飞米是十亿分之一米。