[SFDXA] THE GREAT SOLAR STORM OF MARCH 1940:

[Bill]

*THE GREAT SOLAR STORM OF MARCH 1940:* This story is shocking. On March 
24, 1940, a solar storm hit Earth so hard it made copper wires in the 
United States crackle with 800 volts of electricity. A /New York Times/ 
headline declared that a "sunspot tornado" had arrived, playing havoc 
with any signal that had to travel through metal wires.

"For a few hours it completely disrupted all long-distance 
communication," wrote astronomer Seth B. Nicholson in a recap of the 
event 
<https://articles.adsabs.harvard.edu/full/seri/PASP./0052//0000171.000.html> 
for the /Astronomical Society of the Pacific/. Radio announcers seemed 
to be "talking a language no one could understand."

<https://spaceweather.com/images2023/09aug23/headline.jpg>

The /New York Times/ reported 
<https://spaceweather.com/images2023/09aug23/added.jpg> that more than a 
million telephone and teletype messages had been garbled. "Veteran 
electrical engineers unhesitatingly pronounced it the worst thing of its 
kind within their memory."

So why have you never heard of this storm? Even in 1940 it was fairly 
quickly forgotten. World War II was underway in Europe, and the USA was 
on the verge of joining. People had other things on their minds.

Modern researchers, however, are paying attention. A team led by Jeffrey 
Love <https://jeffreylove.org> of the USGS Geomagnetism Program 
<https://www.usgs.gov/programs/geomagnetism> just published a new study 
of the event in the research journal /Space Weather/. Their work 
confirms that it was no ordinary solar storm.

"It was unusually violent," says Love. "There were very rapid changes in 
Earth's magnetic field, and this induced big voltages in long metal wires."

Love and colleagues learned about the voltages from old engineering 
reports. In 1940, the United States was cross-crossed by copper wires 
hundreds to thousands of miles long. They were not for power 
distribution; electrical systems were still mostly regional. Instead the 
wires were used for communications such as telephone calls and 
telegrams. When the "sunspot tornado" hit Earth, electricity began to 
move through the system. Technicians jotted down some of the voltages 
they saw--and the numbers were incredible.

<https://spaceweather.com/images2023/09aug23/shockingvoltages.jpg>
*Above:* Solar storm voltages in March 1940 (red) vs. the Quebec 
Blackout of March 1989 (blue)

"Records show 400 V in Minnesota, 750 V in Missouri, and more than 800 V 
in Massachusetts," says Love. "These are 10 times greater than long-wire 
voltages recorded during the Great Quebec Blackout 
<https://spaceweatherarchive.com/2021/03/12/the-great-quebec-blackout/> 
in March 1989."

What caused the high voltages? Love's team examined old magnetogram 
records from the date of the storm and found evidence that two coronal 
mass ejections CMEs hit Earth only 1.82 hours apart. The double blow 
rattled Earth's magnetic field in a complicated way most single CMEs do 
not.

"This could be a harbinger of things to come," says Love. Modern studies 
show that as many as 5 CMEs leave the sun every day during Solar 
Maximum. With Solar Cycle 25 underway and intensifying, a double hit 
could definitely happen again.

A similar storm today might not significantly impact communications; we 
live in the wireless age of cell phones. Electricity is another matter. 
Modern power systems depend on long wires to shuttle electricity across 
the country. A repeat of 1940 could interfere with their 
operations. Love notes that the 1940 voltages exceed NERC 
<https://www.nerc.com/Pages/default.aspx> power-grid industry benchmarks 
for 100-year storms. As a result, some modern power grids might not be 
ready to handle the shock of another 1940 event.

Read Love's original research here: here 
<https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2022SW003379>.

https://spaceweather.com/

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