Our lives are surprisingly dependent upon this extremely light and unreactive gas, yet supplies of it are remarkably fragile.

Nancy Washton remembers the sinking feeling she got when she heard her helium delivery wouldn't be arriving. In early 2022, she and her team of chemists at the Pacific Northwest National Laboratory in the United States were abruptly told by their supplier that they wouldn't get their usual shipment of the gas, which they use in a range of different experiments.

Shortages meant there wasn't enough to go around, and the laboratory would simply have to make do with less. In the first weeks of that year, the laboratory's supply dropped well below the 2,500 litres (660 gallons) it normally received. By April, just a couple of months later, it was getting less than half the helium it needed.

With a small fleet of instruments that require regular top-ups of liquid helium, the lab had no choice but to sacrifice the greediest of these in order to continue running the most important. Washton's own instrument of choice was a nuclear magnetic resonance spectrometer – a huge, hulking tower, capable of peering into the molecular structure of atoms. Such measurements can contribute to the development of new batteries and energy storage systems, for example.

The spectrometer was the only one of its kind in North America, and less than 12 months after its installation it was providing results that were potentially game-changing. When turned on samples of magnesium oxide, for example, it showed the minerals are capable of pulling carbon out of the atmosphere. Such "carbon mineralisation" has long been explored as a way of combatting greenhouse gas emissions, but the results showed how useful these minerals could be.

"There had been no definitive evidence of carbonate formations on these particular types of magnesium oxides [before]," says Washton. "I just could not believe the data. The fact that we had managed to get this data, and the beauty of the story it told, was just amazing," Washton says.

But then all of that work abruptly had to stop.

The rate at which the spectrometer consumed helium made it a problem. In a process Washton later described as "traumatising", the instrument was de-energised and mothballed, its experiments suspended. It would sit inert and useless for several months until more helium could be secured. Today, the device is back up and running – the lab has the helium it needs. For the time being.

What is helium used for?

Helium is an inert gas, which means that it does not react readily with other substances. It has the lowest boiling point of any element at -269C (-452F) and a low density.

The space industry uses helium to keep satellite instruments cool and to clean out rocket engines. It is also used to pressurise the fuel tanks of space rockets.

Helium also cools equipment within the Large Hadron Collider (LHC) as well as the superconducting magnets in medical MRI scanners.

Helium is often used to fill party balloons, weather balloons and airships due to its low density.

Deep-sea divers rely on helium to control the proportions of oxygen and nitrogen they get from their breathing apparatus, since this helps to avoid decompression sickness.

The episode highlights how vulnerable helium supplies are and why there is now a desperate scramble around the world to find ways of conserving and recycling this crucial gas.

The shortages in 2022 didn't just affect researchers. You might not realise it, but many of the products and processes you encounter each day depend on helium.

Hospitals, for example, are the world's largest consumers of helium, accounting for around 32% of the global market. The gas is used to cool magnets in vital diagnostic tools such as magnetic resonance imaging (MRI) scanners. Helium is also used in the manufacturing of the semiconductors (computer chips), which are at the heart of electronic devices. It's also used in welding and even pressurises the fuel tanks of rockets that put satellites into orbit. Plus, helium is part of the gas mixture that inflates car safety airbags.

Helium is odourless, extremely light and, unlike another very light element once used in airships, hydrogen, it will never burst into flames. When cooled, it only condenses into a liquid at the stunningly low temperature of roughly 4.2 Kelvin, or -269C/-452F. Plus, under normal atmospheric conditions, helium will not freeze even at temperatures as low as absolute zero, or 0 Kelvin (-273C/-460F). This makes it incredibly useful.

"Helium is a magical element," says Sophia Hayes, professor of chemistry at Washington University in St. Louis. "There is nothing else like it in the Universe."

Liquid helium takes on strange properties when it is chilled almost to absolute zero, turning into a superfluid that flows without friction. Stir a cup of superfluid helium and the liquid inside would theoretically keep spinning forever. Superfluid helium has become vital for large-scale superconductors, such as those used by the Large Hadron Collider experiment at Cern on the border between Switzerland and France.

But since 2006, helium has repeatedly been in short supply. The most recent extended shortage started in January 2022 before easing the following year. But helium supplies have remained precarious, with

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