How do they make helium? It’s an inert gas!

Dear Cecil:

How do they make helium? Think about it. It's an inert gas that doesn't combine with anything else, so there can't be helium mines filled with helium ore. The only place I've ever heard of where you can find a lot of helium is the sun, where it's created by fusion. Fusion is prohibitively expensive on earth, yet somehow commercial helium is cheap enough that they can fill toy balloons with it. What's the deal?

Cecil replies:

Come now, Bob, everybody knows fusion isn’t the only way to make helium. It’s also a by-product of radioactive decay. (The “alpha particles” emitted by some radioactive materials are actually helium atoms minus the electrons.) To get helium all you have to do is find yourself a planet full of uranium and thorium and the like, wait ten jillion years, and presto, you’re up to your ankles in the stuff. The helium on the earth’s surface drifts off into space, but underground a lot of it collects in pockets of natural gas, particularly in the gas fields of the southwestern U.S. Liquefy the natural gas and filter out impurities and what’s left will float a dirigible, cool a nuclear reactor, or make the strongest man sound like a chipmunk. Definitely one of nature’s noble gases.

Send questions to Cecil via cecil@straightdope.com.

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