Cosmic Rays Continue to Intensify

Researchers have long known that solar activity and cosmic rays have a yin-yang relationship. As solar activity declines, cosmic rays intensify. Lately, solar activity has been very low indeed. Are cosmic rays responding? The answer is “yes.” Spaceweather.com and the students of Earth to Sky Calculus have been using helium balloons to monitor cosmic rays in the stratosphere. Their data show that cosmic rays in the mid-latitude stratosphere now are approximately 12% stronger than they were one year ago:


Cosmic rays, which are accelerated toward Earth by distant supernova explosions and other violent events, are an important form of space weather. They can seed clouds, trigger lightning, and penetrate commercial airplanes. Furthermore, there are studies linking cosmic rays with cardiac arrhythmias and sudden cardiac death in the general population. Among patients who have an implanted cardioverter – defibrillator (ICD), the aggregate number of life-saving shocks appears to be correlated with the number of cosmic rays reaching the ground. References: #1, #2, #3, #4.

Why do cosmic rays increase when solar activity is low? Consider the following: To reach Earth, cosmic rays have to penetrate the inner solar system. Solar storms make this more difficult. CMEs and gusts of solar wind tend to sweep aside cosmic rays, lowering the intensity of radiation around our planet. On the other hand, when solar storms subside, cosmic rays encounter less resistance; reaching Earth is a piece of cake.

Forecasters expect solar activity to drop sharply in the years ahead as the 11-year solar cycle swings toward another deep minimum. Cosmic rays are poised to increase accordingly.

Cosmic Rays Continue to Intensify

Last month, we reported that cosmic rays are intensifying. Measurements so far in February indicate that the trend is continuing. In fact, the latest balloon flight over California on Feb. 5th detected the highest value yet:

The data show that cosmic rays in the mid-latitude stratosphere now are approximately 10% stronger than they were one year ago. All of these measurements were collected by Spaceweather.com and the students of Earth to Sky Calculus.

Cosmic rays, which are accelerated toward Earth by distant supernova explosions and other violent events, are an important form of space weather. They can seed clouds, trigger lightning, and penetrate commercial airplanes. Indeed, our measurements show that someone flying back and forth across the continental USA, just once, can absorb as much ionizing cosmic radiation as 2 to 5 dental X-rays. Likewise, cosmic rays can affect mountain climbers, high-altitude drones, and astronauts onboard the International Space Station.

This type of radiation is modulated by solar activity. Solar storms and CMEs tend to sweep aside cosmic rays, making it more difficult for cosmic rays to reach Earth. On the other hand, low solar activity allows an extra dose of cosmic rays to reach our planet. Indeed, the ongoing increase in cosmic ray intensity is probably due to a decline in the solar cycle. Solar Maximum has passed and we are heading toward a new Solar Minimum. Forecasters expect solar activity to drop sharply in the years ahead, and cosmic rays are poised to increase accordingly. Stay tuned for more radiation.