TGF Expose Airline Passengers to Radiation

Many people know that gamma-ray bursts (GRB) are the most intense and energetic explosions in the entire Universe, when amazing quantities of radiation are emitted and accelerated at nearly the speed of light. The Earth's atmosphere protects us from these cosmic events to some extent, but not many people know that it also produces similar radiation of its own. Telescopes scanning the skies for GRB have identified what are called terrestrial gamma-ray flashes (TGFs), which occur at about the same altitude where commercial jet airliners fly, Space Fellowship reports.

TGFs most often occur during thunderstorms, where they blast to the clouds very close to airplanes. According to a recently published investigation, the distance may actually be too close for the passengers' sake, in the sense that being hit by a TGF is equivalent to receiving the same amount of radiation as provided by 400 chest X-rays. And this happens all at once, not during several years. In fact, these flashes occur over milliseconds, thousands of a second, and deliver all the aforementioned radiation to whatever happens to be in the way at the time.

One of the members of the group that conducted the research was Florida Institute of Technology (Florida Tech) expert Joe Dwyer. He and colleagues used the NASA Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) in order to investigate the threat level posed by TGF. “We believe the risk of encountering a TGF in an airplane is very small. I wouldn’t hesitate to take a flight. Pilots already avoid thunderstorms because of turbulence, hail, and lightning, and we may just have to add TGG to the list of reasons to steer clear of those storms. [However], it’s worth looking into,” the expert says.

Future studies into this matter will also benefit from the assistance of the Gamma-Ray Burst Monitor (GBM) instrument aboard the NASA Fermi Gamma-ray Telescope. “GBM provides the best TGF data we have so far. It gets better measurements of their spectra than any previous instrument, giving us a more accurate idea of just how energetic they are,” Dwyer says. He adds that the photons emitted during TGF are up to ten million times more energetic than the ones making up visible light. This means that they pack a sufficiently large punch to penetrate several inches of solid lead.

“It’s amazing. They come blasting right through the whole Fermi spacecraft and light up all of our detectors. Very few cosmic gamma-ray bursts manage to do this!” GBM co-investigator Jerry Fishman concludes.