The most popular Physics Today articles of 2022

Each December we review the year’s most popular stories on Physics Today‘s website. The list below includes the most-read pieces of 2022 and the most shared, as measured by Altmetric score .

Most read

1. Helium is again in short supply (published online 4 April)

Three years ago, helium supplies were so strained by ballooning industrial demand that some experimental physicists and chemists were forced to decommission their cryogenic superconducting magnets. Then the pandemic hit, helium demand for industrial applications and for party balloons plummeted, and supply recovered . This year’s most-read Physics Today article lays out why scientists and industry have been dealing lately with another helium shortage. As David Kramer explains, unplanned temporary shutdowns of helium-producing facilities in the US and Russia proved too much for the market to handle. Concerns over helium supply are likely to continue due to the prominent role of Russia in the global supply chain for the precious noble gas.

2. Does quantum mechanics need imaginary numbers? (March issue)

“In electromagnetism and most other fields of physics, imaginary numbers are merely a mathematical convenience,” writes Johanna Miller. But “there’s no simple way to remove them” in quantum mechanics. Miller reports on work that investigated whether imaginary numbers are truly needed in quantum theory. Given some assumptions, the researchers found that the predictions of the complex-valued formulation of quantum theory cannot be matched by real-valued alternative versions.

Miller’s story was the most read of several articles on quantum weirdness that proved popular this year. In consecutive issues this summer, David Mermin and Sean Carroll offer their takes on the passionate debate over, as Carroll puts it, “what precisely happens when a quantum measurement is performed.” Then in October, as Physics Today editors were sorting through numerous reader responses to the Mermin and Carroll articles, the Nobel Prize in Physics was awarded to a trio of physicists for their foundational quantum entanglement experiments . For context on the Nobel-winning research, see Mermin’s 1985 explainer “Is the Moon there when nobody looks?” and Reinhold Bertlmann’s 2015 article describing the work of his friend and colleague John Bell.

3. Why did the Three Mile Island Unit 1 reactor close? (June issue)

The Three Mile Island nuclear power plant in south-central Pennsylvania has two pressurized water-reactor units. Unit 2 (right in the photo above) was the site of the infamous 1979 nuclear accident . But the lesser-known Unit 1 (left) was restarted in 1985 and had been providing energy to more than 800 000 homes before it was shut down in 2019, a decade and a half before its license expired. In their June feature article, Hannah Pell, Ryan Hearty, and David Allard use the case of the Unit 1 reactor to explore how the life span of nuclear power plants depends on regional energy markets, state regulations, and community activism.

4. The mysterious balancing stones on frozen lakes (September issue)

The cover photo of the September issue , taken at Lake Baikal in Siberia, features a stone balancing on a thin pedestal of ice. In that issue’s Quick Study, physicist Nicolas Taberlet describes his efforts to reproduce the mysterious phenomenon in the lab. Using an aluminum disk as an analogue, Taberlet and a colleague show how an opaque object placed on ice can act as an umbrella that blocks out incoming sunlight. The umbrella effect decreases the sublimation rate beneath the object and is most pronounced at the center. The result of the process, also known as differential ablation, forces the object to “remain at a constant altitude on an increasingly taller and narrower foot of ice until it eventually falls off,” Taberlet writes. He describes that effect and others that contribute to the balancing stones and to related phenomena such as glacier tables .

5. CERN’s Higgs boson discovery: The pinnacle of international scientific collaboration? (published online 30 June)

This summer was the 10th anniversary of the discovery of the Higgs boson . In a year marked by Russia’s invasion of Ukraine, historian of science Michael Riordan reminds readers about the extraordinary degree of international cooperation that enabled the detection of the long-sought particle at CERN’s Large Hadron Collider. He argues that CERN’s diplomatic and scientific success positions it well for future major projects in high-energy physics. “National governments require strong assurances that the money and equipment they send abroad for scientific megaprojects are being well managed on behalf of their scientists and citizenry,” he writes. “In that regard, CERN has a remarkably robust, decades-long track record.” The essay was one of several articles published to commemorate the anniversary .

Most shared

1. STEM scholars worldwide express solidarity with Iranian protesters (published online 19 October)

Just over a month after 22-year-old Mahsa Amini died in the custody of Iranian police, more than 2600 STEM scholars and allies from around the world signed a statement that affirmed support of the women’s and human rights protest movement in Iran. In addition to reporting on the statement, Toni Feder describes how Iranian women in STEM face barriers such as not being allowed to attend meetings outside the country without the consent of a male guardian. A significant percentage of the several hundred people who shared the article on Twitter were based in Iran, according to Altmetric.

2. Prominent Ukrainian physics institute imperiled by Russian attacks (published online 7 March)

Among the many concerns stemming from Russia’s invasion of Ukraine is damage to nuclear power plants and to scientific facilities with nuclear reactors. During the second week of the war, Russian shelling damaged parts of the recently installed neutron source at the Kharkiv Institute of Physics and Technology, raising fears of a radiological disaster. Looking into the neutron facility, I learned that the Kharkiv nuclear reactor does not reach criticality and that there was no highly enriched uranium on-site. The story also explores the history of the Kharkiv physics institute, which has hosted physicists such as Lev Landau, Ilya and Evgeny Lifshitz, and Lev Shubnikov.

3. Physics . . . is for girls? (August issue)

Stereotypes don’t last forever. Case in point: In the US, the idea that physics is a boy’s subject is only about 100 years old. Two centuries ago, physics (or, as it was called then, natural philosophy) was considered more of a girl’s subject, historian of physics Joanna Behrman explains in her August cover story . The reasons that was the case, and why it changed in the 20th century, center on the evolving cultural connection between natural philosophy and religion. “It goes to show how impermanent culture really is, and how much it depends on the context of time and place,” Behrman writes. “And if culture can change over time, let us undertake the effort to change it for the better.”

4. Advancing equity, diversity, and inclusion: a how-to guide (January issue)

It’s one thing to support equity, diversity, and inclusion in physics; it’s another to work actively to improve representation in the community. In the January issue, Rowan Thomson of Carleton University in Ottawa, Canada, lays out concrete actions available to students, senior physicists, and everyone in between. They include practicing allyship, organizing inclusive scientific meetings, and raising the visibility of diverse physicists. Thomson’s recommended resources include Ann Nelson’s powerful 2017 commentary on diversity and the annual #BlackInPhysics Week essay series, which this year includes six pieces that address the theme of finding joy in the physics community.

5. Commentary: Is physics too specialized? (published online 13 January)

Liam Lau and Ethan van Woerkom noticed that as they progressed in their physics graduate programs, their skills and knowledge rapidly diverged from each other’s and from those of their classmates. That made them wonder about the proper balance between mastering a specialty and maintaining at least an informed understanding of progress in other subfields. For their January commentary, Lau and Van Woerkom spoke to several scientists who found success by either switching fields or bringing an interdisciplinary approach to solving problems. They encourage institutions to reward researchers who complement their specialized skills with broad knowledge, and they advocate for more grant and fellowship opportunities for scientists to work in areas outside their field of expertise.