Helium-3 has one less neutron than regular helium (helium-4) and is also produced in the sun and almost as quickly consumed in fusion reactions as deuterium.

氦- 3比普通氦(氦- 4)少一个中子，并且同样在太阳里产生然后象氘一样在核聚变中迅速被消耗掉。

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Like deuterium, it is rare relative to helium-4, but, unlike hydrogen, helium doesn't form chemical compounds as abundant as water.

象氘一样，相对于氦- 4它是非常罕见的，但是不同于氢，氦不是来自化学混合物象水那样丰富。

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What helium is available is depleted in helium-3 relative to what we see in the sun, because most of Earth's helium-4 is freshly made via natural radioactive decay of the elements uranium and thorium.

当氦衰变成为氦-3相对于我们在太阳里看到的那它就可用了，因为地球上多数的氦-4是通过元素铀和钍自然放射性衰变而造成的。

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Terrestrial helium, for example, consists of a small amount of helium-3 (the nucleus of which has two protons and one neutron), and mostly helium-4 (which has 2 protons and 2 neutrons).

BBC: ET gases caged on Earth

"It'll hold about 4, 500 cubic feet of helium, " says Piper.

WSJ: Up in the Air | Making It