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Lightning. Photo: 4FR / iStock

Lightning can create fusion reactions in the air around it, according to research published today in the journal Nature. Nuclear reactions were thought to occur in some thunderstorms but the study provides the first conclusive evidence they are happening.

Why it matters: It's unclear how thunderstorms and lightning work. "How lightning initiates inside thunderstorms is a complete mystery, and how lightning initially moves inside the storms is not at all clear," lightning expert Joseph Dwyer from the University of New Hampshire tells Axios in an email. He says figuring out how some thunderstorms emit huge gamma-ray flashes thought to trigger the reactions "might tell us something interesting about what's going on inside the storms."

The question: It seems theoretically impossible for lightning to produce nuclear fusion reactions because the fuel for the reactions — a form of hydrogen called deuterium — isn't available in large enough amounts in the atmosphere. The 50,000°F temperature of lightning is also a lot cooler than the 30,000,000°F near the center of the Sun where nuclear fusion occurs. Yet scientists have observed by-products of these reactions being produced from lightning.

How it works: Lightning can emit high-energy bursts known as gamma-ray flashes. (How and when they occur — they are associated with a small fraction of lightning seen around the world each day — is a mystery itself.) The flashes are energetic enough to knock neutrons out of the nuclei of nitrogen and oxygen in the air, creating radioactive versions of them for a short time.

Researchers have seen signatures of neutrons being formed just after a lightning flash before. The new paper reports a second such observation on February 6, 2017 Japan along with detection of the radioactive nitrogen and oxygen produced when neutrons are removed from their nuclei.

"It leaves no possible doubt as to what's going on, and it's a beautiful and thorough analysis," says David Smith, a physicist at the University of California Santa Cruz who studies gamma-rays produced by lightning and wasn't involved in the research.

What's next: The gamma-ray flashes themselves were too bright for the researchers' instruments to record. Dwyer says having better instrumentation in places where there are lots of thunderstorms and on aircraft flying near storms would be a very important next step to confirm the bursts start the reactions.

Go deeper

Police officers' immunity from lawsuits is getting a fresh look

Illustration: Aïda Amer/Axios

Nearly a year after the death of George Floyd, advocates of changes in police practices are launching new moves to limit or eliminate legal liability protections for officers accused of excessive force.

Why it matters: Revising or eliminating qualified immunity — the shield police officers have now — could force officers accused of excessive force to personally face civil penalties in addition to their departments. But such a change could intensify a nationwide police officer shortage, critics say. 

The U.S. coronavirus vaccines aren't all the same

Illustration: Eniola Odetunde/Axios

The U.S. now has three COVID-19 vaccines, and public health officials are quick — and careful — to say there’s no bad option. But their effectiveness, manufacturing and distribution vary.

Why it matters: Any of the authorized vaccines are much better than no vaccine, especially for people at high risk of severe coronavirus infections. But their differences may fuel perceptions of inequity, and raise legitimate questions about the best way to use each one.

Erica Pandey, author of @Work
2 hours ago - Economy & Business

The future of workplace benefits

Illustration: Annelise Capossela/Axios

The pandemic exposed how workplaces across America are inhospitable to parents. But it could also spur companies to make changes.

The big picture: Well over a million parents have left their jobs due to child care responsibilities during the pandemic. Now, companies — large and small — are attempting to reimagine workplace benefits and add flexibility to help those parents come back.