Archive for the ‘Geomagnetism’ Category

They don’t make them like that any more – we hope.

July 9, 2022: Sixty years ago today, one of the biggest geomagnetic storms of the Space Age struck Earth. It didn’t come from the sun.

“We made it ourselves,” recalls Clive Dyer of the University of Surrey Space Centre in Guildford UK. “It was the first anthropogenic space weather event.”

On July 9, 1962, the US military detonated a thermonuclear warhead 250 miles above the Pacific Ocean–a test called “Starfish Prime.” What happened next surprised everyone. Witnesses from Hawaii to New Zealand reported auroras overhead, magnificent midnight “rainbow stripes” that tropical sky watchers had never seen before. Radios fell silent, then suddenly became noisy as streetlights went dark in Honolulu.

Above: ‘Nuclear auroras’ viewed from Honolulu (left) and from a surveillance aircraft (right) on July 9, 1962.

Essentially, Starfish Prime created an artificial solar storm complete with auroras, geomagnetic activity, and blackouts. Much of the chaos that night was…

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Beware ‘unusual frequencies (harmonics)’.

June 13, 2022: Researchers have mapped the best and worst places to be in the USA during a severe geomagnetic storm. For residents of some big cities, the news is not good.

“Resistive structures in the crust and mantle of the Earth make cities along the east coast of the USA especially vulnerable to geomagnetic storms,” says Jeffrey Love of the US Geological Survey (USGS), who led the study. “The hazards are greatest for power systems serving Boston, New York, Philadelphia, Baltimore, and Washington, DC, – a megalopolis of over 50 million people.”

Above: If you live near an orange dot you might be in trouble. Peak geoelectric field amplitudes during the March 13, 1989, geomagnetic storm, from Love et al (2022).

These conclusions are based on a new study of the biggest geomagnetic storm of the Space Age–the Great Québec Blackout. On March 13, 1989, two major CMEs hammered…

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Something similar was also detected on Mars a few years ago. One researcher commented: “The sudden intensification of a ring current causes the main phase of a magnetic storm.” Coronal mass ejections from the sun were identified as a cause.
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An international team of scientists has proved that Mercury, our solar system’s smallest planet, has geomagnetic storms similar to those on Earth, says Science Daily.

Their finding, a first, answers the question of whether other planets, including those outside our solar system, can have geomagnetic storms regardless of the size of their magnetosphere or whether they have an Earth-like ionosphere.

The research by scientists in the United States, Canada and China includes work by Hui Zhang, a space physics professor at the University of Alaska Fairbanks Geophysical Institute.

Their finding, a first, answers the question of whether other planets, including those outside our solar system, can have geomagnetic storms regardless of the size of their magnetosphere or whether they have an Earth-like ionosphere.


The Starlink Incident

Posted: February 10, 2022 by oldbrew in Geomagnetism, satellites, solar system dynamics

Looks like the risks were seriously underestimated if this was only a minor geomagnetic storm.

Feb. 9, 2022: As many as 40 Starlink satellites are currently falling out of the sky–the surprising result of a minor geomagnetic storm. SpaceX made the announcement yesterday:

“On Thursday, Feb. 3rd at 1:13 p.m. EST, Falcon 9 launched 49 Starlink satellites to low Earth orbit from Launch Complex 39A (LC-39A) at Kennedy Space Center in Florida. … Unfortunately, the satellites deployed on Thursday were significantly impacted by a geomagnetic storm on Friday, [Feb. 4th].”

Two days before launch a CME hit Earth’s magnetic field. It was not a major space weather event. In fact, the weak impact did not at first spark any remarkable geomagnetic activity. However, as Earth passed through the CME’s wake, some sputtering G1-class geomagnetic storms developed. It was one of these minor storms that caught the Starlink satellites on Feb. 4th.

Geomagnetic storms heat Earth’s upper atmosphere. Diaphanous tendrils of warming air literally reached up…

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Diagram showing solid-body rotation of the Earth with respect to a stationary spin axis due to true polar wander. [Credit: Wikipedia]

The researchers say their finding ‘challenges the notion that the spin axis has been largely stable over the past 100 million years.’
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We know that true polar wander (TPW) can occasionally tilt whole planets and moons relative to their axes, but it’s not entirely clear just how often this has happened to Earth, says ScienceAlert.

Now a new study presents evidence of one such tilting event that occurred around 84 million years ago – when dinosaurs still walked the Earth.

Researchers analyzed limestone samples from Italy, dating back to the Late Cretaceous period (100.5 to 65.5 million years ago), looking for evidence of shifts in the magnetic record that would point towards an occurrence of TPW.

Bacteria fossils trapped in the rock, forming chains of the mineral magnetite, offer some of the most convincing evidence yet of true polar wander in the Late Cretaceous – and it may help settle a scientific debate that’s been going on for decades.


Nov. 4, 2021: Auroras in California? Believe it. On Nov. 4th, the glow of a strong (G3) geomagnetic storm spread almost to Los Angeles. Aurora chaser Hongming Zheng took this picture just outside Lincoln CA at latitude +39N:

“This was my southernmost aurora sighting yet!” says Zheng. “A red glow and occasional pillars were visible to the naked eye. I was very pleasantly surprised with this unexpectedly strong geomagnetic storm.”

More reds appeared in Joshua Tree, California (+34N). “I could not see them with my naked eye,” says veteran observer Don Davis, “but my camera recorded these rare SoCal auroras.”

The CME that sparked the display was a special “Cannibal CME“–that is, a mashup of multiple solar storm clouds striking Earth all at once. Cannibal CMEs contain tangled magnetic fields and compressed plasmas that often do a good job sparking auroras.

At the apex of…

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Quote: “the majority of [low Earth orbiting] satellites were temporarily lost, requiring several days of around-the-clock work to reestablish [their positions].” — Beware solar flares.

Oct. 29, 2021: Imagine waking up to this headline: “Half of Earth’s Satellites Lost!” Impossible? It actually happened on an October day in 2003.

Turn back the clock 18 years. Solar Cycle 23 was winding down, and space weather forecasters were talking about how quiet things would soon become when, suddenly, the sun unleashed two of the strongest solar flares of the Space Age. The first, an X17-category blast on Oct. 28, 2003, hurled this CME directly toward Earth:

Above: A CME heading straight for Earth on Oct. 28, 2003. The source was an X17-flare in the magnetic canopy of giant sunspot 486. Image credit: SOHO. Movie

Traveling 2125 km/s (almost 5 million mph), the cloud slammed into Earth’s magnetic field only 19 hours later, sparking an extreme (G5) geomagnetic storm. The storm had barely begun when the sun erupted again. An X10-flare on Oct. 29th created another…

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The next year or two may give us a better idea of how solar cycle 25 is going to turn out, compared to other cycles.

Oct. 21, 2021: Paolo Bardelli will never forget Oct. 21, 2001. “The sky over my hometown in Italy suddenly filled with intense red auroras,” he recalls. “This happened exactly 20 years ago today.”

Above: Red auroras over Tradate, Italy (latitude +45N), on Oct. 21, 2001. Photo credit: Cesare Guaita

A trip down memory lane: In 2001, Solar Cycle 23 was peaking and solar activity was very high. Strong flares were a daily occurance. On Oct. 19th, giant sunspot AR9661 erupted twice in quick succession, producing almost identical X1.6-class solar flares. The double blast hurled two bright CMEs toward Earth: CME #1, CME #2.

This is what the sun looked like that day:

The first CME took only two days to reach Earth. It was fast and potent. The storm cloud’s arrival on Oct. 21, 2001, ignited a severe geomagnetic storm (Kp=8). Solar wind speeds in the CME’s wake…

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Professor says it’s “a giant feedback loop in space.”

Sept. 20, 2021: No solar storms? No problem. Earth has learned to make its own auroras. New results from NASA’s THEMIS-ARTEMIS spacecraft show that a type of Northern Lights called “diffuse auroras” comes from our own planet–no solar storms required.

Diffuse auroras look a bit like pea soup. They spread across the sky in a dim green haze, sometimes rippling as if stirred by a spoon. They’re not as flamboyant as auroras caused by solar storms. Nevertheless, they are important because they represent a whopping 75% of the energy input into Earth’s upper atmosphere at night. Researchers have been struggling to understand them for decades.

Above: Diffuse auroras and the Big Dipper, photographed by Emmanuel V. Masongsong in Fairbanks, AK

“We believe we have found the energy source for these auroras,” says UCLA space physicist Xu Zhang, lead author of papers reporting the results in the Journal of Geophysical Research: Space…

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Solar flare erupting from a sunspot [image credit:]

Using trees as solar cycle and cosmic ray detectors here. The researchers say: ‘Notably, other evidence suggests that the sun was also undergoing a decades-long period of increasing activity.’ We may ask, with a view to the current era: how often does that happen, and why?
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The sun constantly emits a stream of energetic particles, some of which reach Earth, says

The density and energy of this stream form the basis of space weather, which can interfere with the operation of satellites and other spacecraft.

A key unresolved question in the field is the frequency with which the sun emits bursts of energetic particles strong enough to disable or destroy space-based electronics.

One promising avenue for determining the rate of such events is the dendrochronological record. This approach relies on the process by which a solar energetic particle (SEP) strikes the atmosphere, causing a chain reaction that results in the production of an atom of carbon-14.


First X-flare of Solar Cycle 25

Posted: July 5, 2021 by oldbrew in Cycles, Geomagnetism, News


Is this solar cycle finally lifting off?

July 3, 2021: Now, Solar Cycle 25 has really begun. On July 3rd, new sunspot AR2838 produced the first X-class solar flare since Sept. 2017. NASA’s Solar Dynamics Observatory recorded the extreme ultraviolet flash:

The July 3rd explosion registered X1.5 on the Richter Scale of Solar Flares

A pulse of X-rays ionized the top of Earth’s atmosphere, causing a shortwave radio blackout over the Atlantic Ocean: blackout map. Mariners, aviators, and amateur radio operators may have noticed unusual propagation effects below 30 MHz just after 1429 UT.

X-flares are the strongest kind of solar flare. They are typically responsible for the deepest radio blackouts and the most intense geomagnetic storms. This is the first X-flare of young Solar Cycle 25. More are in the offing. During the previous solar cycle (Solar Cycle 24) the sun produced 49 of them. Forecasters believe that Solar Cycle 25 should be at least…

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Extreme geomagnetic storms are now thought to occur about once every 45 years, or every four solar cycles, on average.

April 30, 2021: Imagine living in Florida. You’ll never see the Northern Lights … right? Actually, the odds may be better than you think. A new historical study just published in the Journal of Space Climate and Space Weather shows that great aurora storms occur every 40 to 60 years.

“They’re happening more often than we thought,” says Delores Knipp of the University of Colorado, the paper’s lead author. “Surveying the past 500 years, we found many extreme storms producing auroras in places like Florida, Cuba and Samoa.”

This kind of historical research is not easy. Hundreds of years ago, most people had never even heard of the aurora borealis. When the lights appeared, they were described as “fog,” “vapors”, “spirits”–almost anything other than “auroras.” Making a timeline 500 years long requires digging through unconventional records such as personal diaries, ship’s logs, local weather reports–often in languages that are foreign to…

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A prediction for the Talkshop to mull over.

April 8, 2021: If you think you are safe from geomagnetic storms, think again. A new study just published in the journal Space Weather finds that powerful storms may be twice as likely as previously thought.

Jeffrey Love of the USGS, who authored the study, analyzed Earth’s strongest geomagnetic storms since the early 1900s. Previous studies looked back only to the 1950s. The extra data led to a surprise:

“A storm as intense as, say, the Québec Blackout of 1989 is predicted to occur, on average, about every four solar cycles. This is twice as often as estimated using only the traditional shorter dataset,” says Love.

Above: The data Love used in his extreme value analysis. Red and blue circles denote the two strongest storms in each solar cycle.

A study like this is part physics, part math, and part detective work.

Love has spent recent years digging deeply into…

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A Surprise Visit from STEVE

Posted: July 18, 2020 by oldbrew in Geomagnetism, solar system dynamics

Nature’s purple haze.

July 16, 2020: Even STEVE wants to see Comet NEOWISE. On July 14th, the geomagnetic phenomenon appeared over Canada, streaking the sky with mauve ribbons of light. Harlan Thomas of Calgary, Alberta, reports: “I was out shooting the comet when I noticed a mauve-looking cloud. Wow!” I thought. “STEVE has come to visit NEOWISE. How cool is that?”


STEVE is a recent discovery. It looks like an aurora, but it is not. The purple glow is caused by hot (3000°C) ribbons of gas flowing through Earth’s magnetosphere at speeds exceeding 6 km/s (13,000 mph). It appears during some geomagnetic storms, often alongside a type of green aurora known as the “picket fence,” also shown in Thomas’s photo.

Statistics suggest that STEVE appears most often in spring and fall. What summoned STEVE in mid-summer? It may have been a CME that grazed Earth’s magnetic field on July…

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This twitter video caught my eye last night, it was taken near Miami a few nights ago. It shows mysterious lights, confirmed from many sources and featured on national US TV channels where it’s reported answers are being demanded from the Pentagon.

Then today my physicist friend Mike McCulloch posted a tweet about some similar phenomena which have been observed for many years in Norway.


Credit: NASA

This BBC link includes a video which shows the weakening of the magnetic field over the last 400 years (under ‘Magnetic flip’ sub-heading).
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In an area stretching from Africa to South America, Earth’s magnetic field is gradually weakening, says

This strange behaviour has geophysicists puzzled and is causing technical disturbances in satellites orbiting Earth.

Scientists are using data from ESA’s Swarm constellation to improve our understanding of this area known as the ‘South Atlantic Anomaly.’


Now believed to be of similar intensity to the more famous Carrington event of 1859.

May 12, 2020: 99 years ago this week, people around the world woke up to some unusual headlines.

“Telegraph Service Prostrated, Comet Not to Blame” — declared the Los Angeles Times on May 15, 1921. “Electrical Disturbance is ‘Worst Ever Known'” — reported the Chicago Daily Tribune. “Sunspot credited with Rail Tie-up” — deadpanned the New York Times.


They didn’t know it at the time, but those newspapers were covering the biggest solar storm of the 20th Century. Nothing quite like it has happened since.

It began on May 12, 1921 when giant sunspot AR1842, crossing the sun during the declining phase of Solar Cycle 15, began to flare. One explosion after another hurled coronal mass ejections (CMEs) directly toward Earth. For the next 3 days, CMEs rocked Earth’s magnetic field. Scientists around the world were surprised when their magnetometers suddenly went offscale, pens in strip chart recorders pegged uselessly…

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Magnetic North on the move [credit: ESA]

It’s down to a process known as ‘flux lobe elongation’, according to researchers. They foresee the magnetic north pole travelling a further 390–660 km towards Siberia.
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European scientists think they can now describe with confidence what’s driving the drift of the North Magnetic Pole, says BBC News.

It’s shifted in recent years away from Canada towards Siberia.

And this rapid movement has required more frequent updates to navigation systems, including those that operate the mapping functions in smartphones.

A team, led from Leeds University, says the behaviour is explained by the competition of two magnetic “blobs” on the edge of the Earth’s outer core.


Magnetic North on the move [credit: ESA]

They have a go at doing so, anyway. To make it more complicated, the South Magnetic Pole is also moving, but at a much lesser rate.

European scientists think they can now describe with confidence what’s driving the drift of the North Magnetic Pole, says BBC News.

It’s shifted in recent years away from Canada towards Siberia.

And this rapid movement has required more frequent updates to navigation systems, including those that operate the mapping functions in smartphones.

A team, led from Leeds University, says the behaviour is explained by the competition of two magnetic “blobs” on the edge of the Earth’s outer core.


Magnetic North on the move [credit: ESA]

Few will notice anything, but some airport runways will have to change their markings.

The team of researchers that maintain the World Magnetic Model (WMM) has updated it and released it a year ahead of schedule due to the speed with which the pole is moving, reports

The newly updated model shows the magnetic north pole moving away from Canada and toward Siberia.

The magnetic north pole is the point on the Earth that compasses designate as true north. It is the result of geological processes deep within the planet—molten iron flow creates a magnetic field with poles near the geographic North and South Poles.