Almost once a week, and the students of Earth to Sky Calculus fly space weather balloons to the stratosphere over California. These balloons are equipped with sensors that detect secondary cosmic rays, a form of radiation from space that can penetrate all the way down to Earth's surface. Our monitoring program has been underway without interruption for 7 years, resulting in a unique dataset of in situ atmospheric measurements.

Latest results (July 2022): Atmospheric radiation is decreasing in 2022. Our latest measurements in July 2022 registered a 6-year low:


What's going on? Ironically, the radiation drop is caused by increasing solar activity. Solar Cycle 25 has roared to life faster than forecasters expected. The sun's strengthening and increasingly tangled magnetic field repels cosmic rays from deep space. In addition, solar coronal mass ejections (CMEs) sweep aside cosmic rays, causing sharp reductions called "Forbush Decreases." The two effects blend together to bring daily radiation levels down.

.Who cares? Cosmic rays are a surprisingly "down to Earth" form of space weather. They can alter the chemistry of the atmosphere, trigger lightning, and penetrate commercial airplanes. According to a study from the Harvard T.H. Chan school of public health, crews of aircraft have higher rates of cancer than the general population. The researchers listed cosmic rays, irregular sleep habits, and chemical contaminants as leading risk factors. A number of controversial studies (#1, #2, #3, #4) go even further, linking cosmic rays with cardiac arrhythmias and sudden cardiac death.

Technical notes: The radiation sensors onboard our helium balloons detect X-rays and gamma-rays in the energy range 10 keV to 20 MeV. These energiesspan the range of medical X-ray machines and airport security scanners.

Data points in the graph labeled "Stratospheric Radiation" correspond to the peak of the Regener-Pfotzer maximum, which lies about 67,000 feet above central California. When cosmic rays crash into Earth's atmosphere, they produce a spray of secondary particles that is most intense at the entrance to the stratosphere. Physicists Eric Regener and Georg Pfotzer discovered the maximum using balloons in the 1930s and it is what we are measuring today.


Hmmm, cosmic rays are at a six year low and they appear to still be decreasing in flux density. The amount of cosmic rays striking the Earth are inversely proportional to the Solar activity.

Solar activity reached moderate levels this week with three M-class
flares observed during the period. Region 3102 (S25, L=298,
class/area Eki/320 on 18 Sep) produced an M1.0/1n flare at 20/1122
UTC. Region 3107 (S25, L=113, class/area Fai/240 on 24 Sep) produced
an M1.0 at 21/0702 UTC. This was followed by the largest event of
the period, an M1.7/Sf at 23/1810 UTC from Region 3110 (N16, L=158,
class/area Dhi/320 on 25 Sep). Associated with this event were Type
II (est. 2453 km/s S.V.) and Type IV signatures. During the period,
a total of 62 C-class and 3 M-class flares were recorded. In
addition to Regions 3102, 3107 and 3110, C-class activity was also
observed from Regions 3105 (S17, L=210, class/area Dki/490 on 22
Sep) and 3109 (N10, L=257, class/area Dro/040 on 23 Sep). Numerous
CME signatures, off of both limbs, were observed in coronagraph
imagery throughout the week, but none were determined to have
Earth-directed components.

No proton events were observed at geosynchronous orbit, although the
10 Mev proton flux was slightly elevated above background levels.

The greater than 2 MeV electron flux at geosynchronous orbit was at
normal to moderate levels on 19-24 Sep and high levels on 25 Sep
with a peak flux of 2,130 pfu observed at 25/1555 UTC.

Geomagnetic field activity mostly ranged from quiet to unsettled
levels with an isolated active period early on 24 September. Quiet
to unsettled periods were observed on 19-20 September under weak,
diminishing, negative polarity coronal hole high stream influence.
Quiet levels were observed on 21 and 22 September, with the
exception of an isolated unsettled period late on 22 September.
Unsettled to isolated active conditions persisted on 24 and 25
September under weak, positive polarity coronal hole high speed
stream influence.

Forecast of Solar and Geomagnetic Activity
26 September - 22 October 2022

Solar activity is expected to be low with a chance for M-class
(R1-R2, Minor to Moderate) flare activity on 26 September to 04
October and from 08-22 October due to current active regions on the
visible disk and returning, active regions.

No proton events are expected at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit is
expected to reach high levels on 26-28 September, 03-12 October and
22 October in response to CH HSS influences.

Geomagnetic field activity is expected to be at unsettled levels on
27-28 September, 01-06 October, 16-17 October, with active levels
possible on 01-05 October and 20-21 October. G1-G2 (Minor-Moderate)
levels are possible on 01-04 October as well. This enhanced activity
is due to CH HSS influences.
Last edited:
Mar 4, 2020
This is a great science story. Science has a lot of monotony. Repetitive measurement and recording data. Every high school should be doing similar measurements of various things. Find sponsors for the cost of the measurements and the students supply the labor. Each high school grade should have a running experiment. The flow rate, temp, pH and turbidity of a near by stream for instance. Or a solar powered weather station. Seismograph, background radiation, or maybe an insect count. Contrail count at noon. A running input and recording of data. Ask the mayor, governor or NASA what data they need in the long term. Or the farmers need. Weed count.

Usefulness in the region will get sponsors. Maybe even more "experiments".
Hayseed -

I agree fully about your high school comment. Tracking any sort of measurements over a period of time will introduce students to the scientific method and provide useful data.