Flying With Cosmic Rays

Flying With Cosmic Rays

In an ongoing experiment to measure space radiation inside commercial airplanes, Dr. Tony Phillips flew from Phoenix to Reno on Jan. 5th, then repeated the trip in reverse on Jan. 6th. Onboard both flights he carried a pair of ionizing radiation detectors sensitive to energies typical of medical X-rays. At cruising altitudes near 39,000 feet, he measured dose rates approximately 40 times higher than at ground level:

The radiation comes from space. Cosmic rays are subatomic particles accelerated to nearly light speed by supernovas, active galactic nuclei, and solar flares. Earth is peppered with this kind of radiation, every day, from all directions. Cosmic rays penetrate our planet's atmosphere, producing a spray of secondary particles that air travelers routinely (and mostly unknowingly) absorb as they fly. According to the rates Phillips measured, a passenger flying for 5 hours would be exposed to about as much radiation as a dental X-ray.
The data for Jan. 5th and Jan. 6th are in good agreement--as they should be. The two planes cruised at almost exactly the same altitude, took off at the same time of day, and traced the same path between Reno and Phoenix. Nevertheless, there is growing evidence of variability. Phillips took the same flight from Reno to Phoenix on Nov. 11, 2014. He measured 40% more radiation then vs. now. The difference is not fully understood.
Stay tuned as the investigation continues.....

From SpaceWeather.com