[CW] The Carrington Event was not Unique

[D.J.J. Ring, Jr.]

https://spaceweatherarchive.com/2020/08/30/a-warning-from-history-the-carrington-event-was-not-unique/

A Warning from History: The Carrington Event Was Not Unique
AUGUST 30, 2020
<https://spaceweatherarchive.com/2020/08/30/a-warning-from-history-the-carrington-event-was-not-unique/>
 / DR.TONY PHILLIPS <https://spaceweatherarchive.com/author/drtonyphillips/>

Sept. 1, 2020: On Sept. 1st, 1859, the most ferocious solar storm in
recorded history engulfed our planet. It was “the Carrington Event,” named
after British scientist Richard Carrington, who witnessed the flare that
started it. The storm rocked Earth’s magnetic field, sparked auroras over
Cuba, the Bahamas and Hawaii, set fire to telegraph stations, and wrote
itself into history books as the Biggest. Solar. Storm. Ever.

But, sometimes, what you read in history books is wrong.

“The Carrington Event was *not* unique,” says Hisashi Hayakawa of Japan’s
Nagoya University, whose recent study of solar storms has uncovered other
events of comparable intensity. “While the Carrington Event has long been
considered a once‐in‐a‐century catastrophe, historical observations warn us
that this may be something that occurs much more frequently.”

[image: carringtonsunspot]

Drawings of the Carrington sunspot by Richard Carrington on Sept. 1, 1859,
and (inset) Heinrich Schwabe on Aug. 27, 1859. [Ref
<https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019SW002269>]
To generations of space weather forecasters who learned in school that the
Carrington Event was one of a kind, these are unsettling thoughts. Modern
technology is far more vulnerable to solar storms than 19th-century
telegraphs. Think about GPS, the internet, and transcontinental power grids
that can carry geomagnetic storm surges from coast to coast in a matter of
minutes. A modern-day Carrington Event could cause widespread power outages
along with disruptions to navigation, air travel, banking, and all forms of
digital communication.

Many previous studies of solar superstorms leaned heavily on Western
Hemisphere accounts, omitting data from the Eastern Hemisphere. This skewed
perceptions of the Carrington Event, highlighting its importance while
causing other superstorms to be overlooked.

A good example is the great storm of mid-September 1770, when extremely
bright
<https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2017SW001693> red
auroras blanketed Japan and parts of China. Captain Cook himself saw the
display <https://ui.adsabs.harvard.edu/abs/1996QJRAS..37..733W/abstract> from
near Timor Island, south of Indonesia. Hayakawa and colleagues recently
found drawings of the instigating sunspot, and it is *twice the size* of
the Carrington sunspot group. Paintings, dairy entries, and other newfound
records, especially from China, depict some of the lowest-latitude auroras
ever, spread over a period of 9 days.

[image: redauroras1770]

An eyewitness sketch of red auroras over Japan in mid-September 1770. [Ref
<https://iopscience.iop.org/article/10.3847/2041-8213/aa9661/pdf>]
“We conclude that the 1770 magnetic storm was comparable to the Carrington
Event, at least in terms of auroral visibility,” wrote Hayakawa and
colleagues in a 2017 *Astrophysical Journal Letter*
<https://iopscience.iop.org/article/10.3847/2041-8213/aa9661/pdf>.
Moreover, “the duration of the storm activity was much longer than usual.”

Hayakawa’s team has delved into the history of other storms as well,
examining Japanese diaries, Chinese and Korean government records, archives
of the Russian Central Observatory, and log-books from ships at sea–all
helping to form a more complete picture of events.

They found that superstorms in February 1872
<https://iopscience.iop.org/article/10.3847/1538-4357/aaca40/meta> and May
1921
<https://spaceweatherarchive.com/2020/05/12/the-great-geomagnetic-storm-of-may-1921/>
 were *also* comparable to the Carrington Event, with similar magnetic
amplitudes and widespread auroras. Two more storms are nipping at
Carrington’s heels: The Quebec Blackout of March 13, 1989, and an unnamed
storm on Sept. 25, 1909, were only a factor of ~2 less intense. (Check
Table 1 of Hayakawa *et al*‘s 2019 paper
<https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019SW002269> for
details.)

[image: 1872]

Oriental reports of a giant naked-eye sunspot group (left) and auroras
(right) in Feb. 1872. [Ref
<https://iopscience.iop.org/article/10.3847/1538-4357/aaca40/meta>]
Contextualizing the Carrington Event has become a busy niche in space
weather research. One team led by Jeff Love of the USGS recently confirmed
<https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019SW002250> the
near equality of Carrington to the May 1921 superstorm. And Hayakawa’s team
has just  unearthed new records of extreme auroras in South America
<https://earth-planets-space.springeropen.com/articles/10.1186/s40623-020-01249-4>
.

Are we overdue for another Carrington Event? Maybe. In fact, we might have
just missed one.

In July 2012, NASA and European spacecraft watched an extreme solar storm
erupt from the sun and narrowly miss Earth. “If it had hit, we would still
be picking up the pieces,” announced Daniel Baker of the University of
Colorado at a NOAA Space Weather Workshop 2 years later. “It might have
been stronger than the Carrington Event itself.”

History books, let the re-write begin.
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