[SFDXA] Cosmic Rays are Increasing at Aviation Altitudes

[Bill]

*Space Weather News for March 13, 2020*
https://spaceweather.com 
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*COSMIC RAYS AT AVIATION ALTITUDES:* New high-altitude balloon 
measurements inside the Arctic Circle show that cosmic rays are 
increasing at aviation altitudes. Commercial flight crews and passengers 
traveling over Earth's poles now experience as much as 12% more 
radiation than they did just a few years ago.


/From SpaceWeather.com

/*NEW ATMOSPHERIC RADIATION MEASUREMENTS**: *We're back from the Arctic, 
and we have some new results to share. In January 2020, the students of 
Earth to Sky Calculus <https://www.facebook.com/earthtoskycalculus> and 
Spaceweather.com traveled to Abisko, Sweden, to launch a pair of cosmic 
ray balloons. We'd been there before, launching three identical balloons 
in March 2017. Putting all the data together, 2017+2020, we find that 
radiation has increased +12% in the past 3 years:

*What's causing the increase?*

Solar Minimum 
<https://spaceweatherarchive.com/2019/04/10/experts-predict-the-solar-cycle/>. 
At the moment, the sun is near the bottom of the 11-year solar cycle. 
During Solar Minimum, the sun's magnetic field weakens, allowing extra 
cosmic rays from deep space to penetrate the solar system. These cosmic 
rays are hitting Earth's atmosphere, creating a spray of secondary 
cosmic rays that shower toward the ground below.

Secondary cosmic rays are what we measure. Radiation sensors onboard our 
helium balloons 
<https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2016SW001410> 
detect X-rays and gamma-rays in the energy range 10 keV to 20 MeV, 
similar to what you get from medical X-ray machines and airport security 
scanners.


We've been launching radiation sensors almost weekly for 5 years--mainly 
from California, the "home base" of Spaceweather.com. Cosmic rays in the 
stratosphere have been increasing 
<https://spaceweatherarchive.com/2019/02/21/cosmic-rays-increasing-for-the-4th-year-in-a-row/> 
the entire time, a sign of deepening Solar Minimum.

The new data from Abisko, Sweden, show the increase is not limited to 
the stratosphere. It is also happening at aviation altitudes with a 
3-year increase of ~12% even below 40,000 ft. We're planning another 
ballooning trip to Sweden in August 2020 to confirm these results. Stay 
tuned.