Tanks of helium, at Doolin Amusement Supply on Thursday, August 22, 2013. | Chandler West/For Sun-Times Media
Updated: September 26, 2013 6:23AM
The sun produces heat — we all know that — from fusion of hydrogen atoms. What is far less known — OK, far, far, far less known — is that, along with heat, the sun also churns out helium.
Which makes it apt that humanity first noticed the existence of helium during a solar eclipse on Aug. 18, 1868, when French astronomer Pierre J. C. Janssen saw an unusual yellow spectral signature around the sun’s corona he realized had to be a new element. British astronomer Norman Lockyer saw the same spectral line and named the element “helium” from “helios,” Greek for sun.
Lockyer assumed this new element had to be a metal, thus gave it an “-ium” ending, like aluminum, lithium and other metals, and not an “-on” ending, like argon and xeon and the other noble gases, of which helium is the leading example, a colorless, odorless liquid loath to react with other elements.
It took 40 years for helium to be found on Earth, hiding in uranium minerals. It’s much more prevalent in natural gas.
We think of helium as useful for its buoyancy in balloons, but equally important is its stability — there are no oxides of helium. It can’t explode. Thus it’s used in welding. Deep sea divers breath a mix of oxygen and helium to prevent the nitrogen in air from getting into their blood and causing the bends.
Helium also can be chilled to extraordinarily cold temperatures, which makes it perfect for cooling things like MRI machines. Helium also has a lighter side. Sound travels three times as fast through helium as in air. Because the wavelengths of sounds the human voicebox emits remain constant, speaking through helium makes the frequency go up so, to compensate; that’s why if you inhale helium, your voice sounds higher. Which has no commercial application but is kinda fun.