The Helium in Macy’s Thanksgiving Day Parade Balloons Could Power Some Sweet Science

The Helium in Macy’s Thanksgiving Day Parade Balloons Could Power Some Sweet Science
A 16.15 m-tall electric mouse soars over Manhattan's Times Square in 2001. (Photo: STAN HONDA/AFP, Getty Images)

The annual Macy’s Thanksgiving Day Parade in New York City uses roughly 400,000 cubic feet of helium gas in total to inflate its iconic giant balloons. Besides being lighter than air and nonflammable — hence its practicality for balloons — helium is incredibly useful as a superconducting agent, making it crucial to many scientific and medical endeavours, including MRI machines and particle accelerators like the Large Hadron Collider. So can you measure an inflatable Snoopy or Pikachu in the amount of science it could be used for?

Helium is one of the lightest and most abundant elements in the universe, but on Earth, the supply is limited. The gas is mostly collected as a byproduct in mining operations. You may have read about helium shortages in the recent past; according to Phil Kornbluth, an expert on the helium market, the pandemic significantly curtailed helium demand. In June 2020, Physics Today reported that, unlike several years ago, “researchers now report they have no trouble getting the helium they need.”

Global demand is now back up after falling during the pandemic, Kornbluth said, though extraction projects in Qatar and eastern Russia mean that the next six months will be a “long-term inflection point for helium supply” globally, with a permanent increase in supply. So there’s no need to shame Macy’s for its once-a-year use of this valuable gas; “Macy’s is a drop in the bucket,” said Kornbluth.

Though volume varies among the balloons — the Macy’s stars are 7.62 m wide and tall, while the Dragon Ball Z Goku is 21.34 m long and 17.07 m tall — on average each balloon is apparently filled with about 12,000 cubic feet of helium, a widely cited figure. (15,000 cubic feet is also widely cited. Macy’s did not respond to Gizmodo’s request for hard numbers.) A standard party balloon contains about 0.4 cubic feet of helium, so you’d need about 30,000 of them to approach the amount of helium used by a single Macy’s balloon.

An 24.38 m-long inflatable superhuman is pinned to the ground on Manhattan's Upper West Side. (Photo: Andrew Burton, Getty Images) An 24.38 m-long inflatable superhuman is pinned to the ground on Manhattan’s Upper West Side. (Photo: Andrew Burton, Getty Images)

Perhaps the most critical scientific use of helium is in medical technologies. Liquid helium is cold enough that it makes magnets in MRI machines superconducting, allowing the devices to take non-invasive, high-quality images of soft tissues inside your body. Newer technologies allow for the reuse of the gas (instead of letting it boil off in Earth’s atmosphere), but conventional MRI machines use about 1,500 and 1,700 litres of liquid helium, an amount that needs to be topped off periodically. Helium has different volumes in different states; 1 litre of liquid helium is equivalent to 26.63 cubic feet of the gas at one atmosphere of pressure, according to one industrial gas supplier. That means, very roughly, that three Macy’s character balloons could provide the helium for one MRI machine.

But there are non-medical uses of the gas, too. Consider the Large Hadron Collider, a massive physics experiment at CERN in Switzerland. All eight curved sections of the collider are cooled down with liquid helium. Accelerating and colliding matter can help physicists discover new particles, like the Higgs Boson in 2012. In 2014, it took 130 metric tons of liquid helium to cool down the entire accelerator; the helium arrived weekly by the truckload, according to Symmetry magazine.

One of the world's most powerful MRIs uses superfluid helium to cool its magnets. (Photo: ALAIN JOCARD/AFP, Getty Images) One of the world’s most powerful MRIs uses superfluid helium to cool its magnets. (Photo: ALAIN JOCARD/AFP, Getty Images)

Helium is also used in astrophysics. Like Macy’s, NASA uses helium to give balloons lift, though NASA’s balloons ascend to much loftier heights. These balloons are used for astronomy, studying Earth’s atmosphere, and detecting high-energy radiation from space. In 2009, the agency signed a five-year contract to spend $US56.5 (A$79) million for 12.5 million litres of liquid helium and 212 million cubic feet of gaseous helium, according to SpaceNews. The agency can use up to 100 million cubic feet of the gas per year, by its own measure. Helium is also used as a purge gas in hydrogen systems, meaning it’s needed for rocket launches. Indeed, NASA is one of the world’s largest consumers of helium, without which many of the agency’s projects literally couldn’t get off the ground.

Since Macy’s began using balloons for its parade, they’ve always contained helium except once, in 1958, when a helium shortage required the company to resort to air-filled balloons, lifted down the avenues with cranes. Hopefully, modern shortages never get so dire.