“Oh Beautiful for smoggy skies, insecticided grain,
For strip-mined mountain’s majesty above the asphalt plain.
America, America, man sheds his waste on thee,
And hides the pines with billboard signs, from sea to oily sea.” -George Carlin
When you think of helium, you very likely think of balloons, birthday parties, and blimps. But this inert, lighter-than-air gas has a number of unique properties among all the elements, including that it’s liquid at very low temperatures and it enters a superfluid state. It’s scientific applications include particle accelerators, MRI machines, and anything else that requires ultra-strong electromagnets.
A modern high field clinical MRI scanner, which achieves magnetic fields of 3 Tesla. Those field strengths can only be achieved with superconducting magnets, which necessitate the use of liquid helium. MRI machines are the largest medical or scientific use of helium today. Image credit: Wikimedia Commons user KasugaHuang.
Yet helium is becoming harder and harder to find, because the way we obtain it is by extracting it from underground reserves. These natural reserves take hundreds of millions of years to form, and once we expel this gas into the atmosphere, almost all of it escapes into interplanetary space. If we don’t start conserving ...