Dark Lightning

February 4, 2023

If you’re a regular here at the Planetary Broadcast Network, you know that one of our self-appointed quests is to clarify the buzzwords that are batted around in the pop news coverage of science. Terms like “dark matter” or “background radiation” often become the flavor of the month, leading to a lot of oversimplification. While it results in higher circulation for the reporter, it also leaves the public with a very shallow (or completely incorrect) understanding. When we notice that has happened, we try to clarify it – but it is often too late. For example, we can never publish enough clarifications to convince the public that quantum teleportation is not going to allow you to beam yourself to work every day; the truth is just not as exciting as the misunderstanding.

Today, however, we are actually on the leading edge of the buzzword envelope. A report shared at the American Geophysical Union meeting last month brought the term “dark lightning” to the attention of the science-adjacent media. It’s the perfect kind of buzzword – no one outside the field knows what it is, but it sounds exotic and dangerous. So far it has only spawned a few articles, but due to one titillating detail about it—that it is reportedly the most energetic naturally-occurring radiation on Earth—we suspect that it may well be the “quantum computing” of the coming months.

To squash any pernicious misunderstandings, dark lightning is a phenomenon that occurs in electrical storms, but it is not lightning in the classic sense. A more accurate (but much less marketable) terminology is “terrestrial gamma-ray flashes.” If you recall your high school physics, you may remember that gamma is the bad kind of ionizing radiation that destroys DNA bonds and causes cancer. 

This all sounds terribly dangerous until you learn a bit about how very rare these events are. They occur when high-velocity electrons strike air molecules in the turbulent winds within a thunderstorm, and are believed to happen only about once per thousand lightning strikes. It generally occurs right before ordinary lightning, and researchers suspect that the strongly charged electrical field is what triggers the gamma-ray burst. They are difficult to detect or measure—each one lasts only 300 milliseconds or so. Luckily, these extremely energetic events happen at an altitude of 10-15 km, an area usually only frequented by airliners.

Here is the next very buzzworthy bit of info about dark lightning—they do sometimes strike airplanes… probably. Because pilots tend to fly around storms, and no one installs gamma-ray detectors on their 747, dark lightning interaction with planes is only hypothetical at this point. Thus far, the only data we have on dark lightning has been gathered by satellites, and even that was an accidental byproduct of the satellites’ primary missions. As with most science reporting, we must conclude with the tired phrase “more research is required,” but it is almost certainly safe to fly without wearing lead underwear. 

We’ll keep you informed on this story as it evolves. Stay tuned to the Planetary Broadcast Network for all the news you need to be an informed member of our great democratic experiment.