#auroras

ramnath@nerdpol.ch

#X-ray #Solar #Flares
6-hr max: #X4 0635 UT May06
24-hr: X4 0635 UT May06

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A #CME expected to hit #Earth on May 5th appears to have arrived right on time. Solar wind data suggest a close encounter around 1800 UT in good accord with NASA and NOAA predictions. The resulting G1-class geomagnetic storm sparked mid-latitude auroras in Europe:

" #Auroras surprisingly appeared here in the Czech Republic at latitude +50 N," reports photographer Petr Horálek at the Institute of Physics in Opava. "They were visible to the naked eye despite the cirrus clouds."

This might not have been a direct hit. Normally, on-target CMEs produce a sharp discontinuity in the speed of solar wind blowing around our planet. Not this time. Instead, a gentle ripple of south-pointing magnetism washed over the Earth for several hours--typical of near-miss CMEs that catch us in their wake.

More CMEs may be on the way. Yesterday's flurry of X- and M-class solar flares from hyperactive sunspot AR3663 probably hurled some debris toward Earth. Confirmation awaits overdue coronagraph data from SOHO

ramnath@nerdpol.ch

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ARCTIC #AURORAS: Around the Arctic Circle, many #aurora tour guides have already packed their cameras for the end of the season. Marianne Bergli of Tromsø, Norway, is glad she waited one more night. "Auroras filled the sky on April 4th," she reports. "It was a fantastic end to our touring season."

A #solar #wind stream brushed Earth's magnetic field on April 4th. It did not cause a global geomagnetic storm; the planetary K-index peaked at 4. Nevertheless, the Arctic light show was sublime.

Soon, summer sunlight will make these displays impossible to see inside the Arctic Circle. That's why Bergli and others are going on vacation. "We start again in September," she says
https://spaceweather.com/

ramnath@nerdpol.ch

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#AURORAS AND THE 'DEVIL COMET': If you want to photograph a beautiful #comet, this is the week to do it. For the next 7+ days, "devil comet" 12P/Pons-Brooks will pop out of the twilight after sunset, its magnificent tail pointing up into the night sky. Michal Kaluzny sends this picture from the Solheimajokull glacier lagoon in #Iceland:

"Fortunately, the auroras weren't too strong, allowing for the delicate tail of the comet to be exposed," says Kaluzny. Also in Iceland, Wioleta Gorecka photographed the comet emerging from a bright green curtain of Northern Lights.

You don't need to be in Iceland to photograph this comet. It's visible around the world, shining like a 5th magnitude star in the constellation Aries. Technically, it's bright enough to see with the naked eye, but in practice you'll need binoculars or a small telescope to pull it out of the western twilight. Cameras with night sky settings should have no trouble recording the comet's tail in wide-angle landscape shot

https://spaceweather.com/

ramnath@nerdpol.ch

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An overdue #CME struck #Earth's #magnetic #field on March 3rd. The impact sparked a #G2-class #geomagnetic #storm and bright #auroras around the Arctic Circle. Jan Eklind photographed the display from the window seat of an Airbus A20N at 35,000 feet:
"I was flying from Oslo to Kirkenes on Scandinavian Airlines when the CME struck," says Eklind. "Auroras spread across the sky with twilight in the distance and city lights below."

The CME was hurled into space on Feb. 28th when a magnetic filament connected to sunspot AR3592 erupted. It was not aimed directly at Earth, and forecasters were unsure if it would deliver even a glancing blow; however, the impact was stronger than expected.
https://spaceweather.com/

nowisthetime@pod.automat.click

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FIRST #AURORAS OF THE YEAR: On Jan. 1st, a crack opened in Earth's magnetic field. Solar wind poured through the gap and fueled the first auroras of #2024. Northern lights tour guide Chris Percival photographed the display over Vesterålen, Norway:

"Our guests had a fantastic display here tonight in Arctic Norway," says Percival. "Shortly after the Moon rose and lit up the landscape, the aurora borealis decided to make a powerful appearance."

The "crack" was formed by the impact of a co-rotating interaction region (CIR). CIRs are transition zones between fast- and slow-moving streams of solar wind. They contain CME-like shocks that open cracks and spark strong Arctic auroras.

https://spaceweather.com/

ramnath@nerdpol.ch

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#Auroras were observed as well -- "and they were INSANE," says Janne Maj Nagelsen, who watched the display from Stamnes, Vaksdal, #Norway:

"I have never seen such strong auroras," says Nagelsen. "Not to mention the colors. I mean look at the picture! They were totally, literally insane."

Auroras are caused by charged particles raining from space down upon Earth's atmosphere. Unlike SAR arcs, which are pure red, auroras can have a rich and stunning variety of colors. Both phenomena may be photographed on Dec. 1, 2023, when a #Cannibal #CME is #expected to hit #Earth.

ramnath@nerdpol.ch

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#CME IMPACT SPARKS EUROPEAN #AURORAS: A CME struck Earth's magnetic field on Nov. 25th, sparking 15 hours of geomagnetic storms. At the apex of the G2-category event, auroras were observed across most of Europe, visible to the naked eye despite nearly full moonlight. Graeme Whipps, who sends this picture from Aboyne, Aberdeenshire, #Scotland (+57N):

Note that Whipps' photo includes a vertical band of rare orange auroras. "What an incredible sight!" Whipps says.

Usually, when auroras visit Europe, they stop in places like Scotland, going no farther south. On Nov. 25th, however, the lights descended all the way to Italy

https://spaceweather.com/

ramnath@nerdpol.ch

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#MYSTERY OF #ORANGE #AURORAS: A recent display of auroras over #Canada has experts scratching their heads. The mystery? They were orange:

"This was a first for me," says Harlan Thomas, who photographed the display over Sibbald Pond west of Calgary, Alberta, on Oct. 19th. "The orange was sublime, just incredible. The pillars in the center stayed there glowing for more than 20 minutes."

Auroras aren't supposed to be orange. Consider the following: Auroras get their colors from atoms and molecules in Earth's atmosphere. During geomagnetic storms, energetic particles rain down from space, striking the air and causing it to glow. Red, green, purple and even pink are common signs of excited oxygen and nitrogen.

The problem is, there's nothing in the air capable of making bright orange. Theoretically, nitrogen and oxygen (N2, N2+, and O2+) can produce emissions at orange wavelengths. However, these emissions are very weak compared to other colors produced by the same molecules. Any orange should be overwhelmed.

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#Aurora colors produced by atoms and molecules in Earth's atmosphere.

The answer may be hiding in plain sight. Take another look at Thomas's photo. Bright red auroras appear on top, overlapping #green auroras lower down. #Red and green mixing together may have produced the #yellow-orange #glow.

Indeed, aurora physicist Kjellmar Oksavik of the University of Bergen in Norway believes that's the correct explanation:

"Red auroras are formed by low-energy electrons colliding with atomic oxygen at high altitudes (200-400 km). Here, oxygen atoms are excited into a quantum state called O(1D), where they can emit a red photon at 630.0 nanometers," Oksavik says.

"Green auroras are formed by higher-energy electrons penetrating deeper and colliding with atomic oxygen at lower altitudes (100-150 km)," he continues. "Here, oxygen atoms are excited into a state called O(1S), where they emit a green photon at 557.7 nanometers."

"In between, there can be a mixing of the two processes, which fools the camera and eye to believe that it is orange. In reality, it is both red and green at the same time," he says.

Oksavik points out one more thing in Harlan Thomas's photo: "It beautifully reveals the alignment of Earth’s magnetic field. The bright pillar in the center is a textbook example of a very tall auroral ray. These are aligned along the magnetic field and caused by a broad energy spectrum of electrons [raining down from space]. Slower electrons collide high up (red light), while more energetic electrons travel further down into a much denser atmosphere (green light)." The overlap naturally produces a yellow-orange glow--no mystery molecule required.

https://spaceweather.com/

ramnath@nerdpol.ch

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GEOMAGNETIC STORM: Arriving a day earlier than expected, a #CME hit #Earth's magnetic field on Sept. 18th. The fast-moving CME triggered a G2-class geomagnetic storm on Sept. 18/19 with bright #auroras around the Arctic Circle. Markus Varik witnessed a "massive powerful outburst" over Tromsø, Norway:

"Last night in Tromsø was simply astonishing," says Varik. "There was no way to prepare ourselves for what we saw."

"I happened to be giving a private aurora tour for two guests, Jose and Kimberly, when the storm erupted," says Varik. "Jose had a plan to propose to Kimberly under the auroras if we were lucky enough to see them. You can guess for yourself, did she say yes?"

https://spaceweather.com/

ramnath@nerdpol.ch

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CIR SPARKS G2-CLASS #GEOMAGNETIC #STORM: If you've never heard of a CIR, there's only one thing you really need to know: CIRs are good at making auroras. One hit Earth yesterday and lit up both ends of our planet--north and south. "The display in #NewZealand was one for the ages," reports Ian Griffin from #Hoopers Inlet on the #Otago Peninsula:

"The #aurora kept pulsing and, just as you thought it was going to end it exploded into life again," he says. "What a night!"

Short for "co-rotating interaction regions," CIRs are transition zones between fast- and slow-moving solar wind streams. Solar wind plasma piles up in these regions, producing shock-like structures that mimic CMEs. NOAA correctly predicted the arrival of a CIR on June 15th. Its impact opened a crack in our planet's magnetic field, fueling a G2-class geomagnetic storm that persisted through June 16th.

Because of the northern summer sun, Arctic observers couldn't see the show. Some #auroras, however, did spill into darkness at lower latitudes. Jeff Berkes sends this photo from #Cape-Cod, #Massachusetts:

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https://spaceweather.com/

ramnath@nerdpol.ch

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#SOLAR #WIND SPARKS #ARCTIC #AURORAS: A co-rotating interaction region (CIR) hit Earth's #magnetic field on Dec. 30th, sparking a G1-class geomagnetic storm. Marianne Bergli photographed the light show from Kvaløya, Tromsø, #Norway:

"The solar wind is blowing out the old year and welcoming the new," says Bergli. "Happy New Year, everyone!"

CIRs are transition zones between slow- and fast-moving streams of solar wind. They contain shock waves and enhanced magnetic fields that do a good job sparking Arctic auroras. Fast solar wind following the CIR sustained the display for hours.
https://spaceweather.com/

ramnath@nerdpol.ch

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A high-speed stream of solar wind hit Earth on Dec. 23rd, sparking G1-class geomagnetic storms and auroras around the Arctic Circle. Markus Varik photographed the light show from Tromsø, #Norway:

"We were on a tour with a small family - parents and their two kids," says Varik. "Once the aurora made their full appearance, they were screaming, laughing, crying, everything you can imagine. It really is overwhelming to experience the #auroras at that full glory."
https://spaceweather.com/

ramnath@nerdpol.ch

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EXPLOSION OF #PINK #AURORAS: If you spend 10 years inside the Arctic Circle, you're going to see a lot of auroras. "I have been guiding aurora tours full time for the past 10 years," says Markus Varik of Tromsø, Norway. "And I thought I I had seen it all." Think again:

"We headed out early last night (Nov. 2nd) to chase the lights--and what a surprise!" he says. "These were the most intense pink auroras I have ever seen. The pink color was bright and obvious to the naked eye. My entire group was stunned."

Pink auroras are a sign of nitrogen. Most auroras are green--the color of #oxygen atoms being struck by energetic particles 100 km to 300 km above #Earth's surface. Pink appears when energetic particles from space descend lower than usual, striking nitrogen molecules at the 100 km level and below.

What happened? Just before Varik went out aurora hunting, a crack formed in Earth's magnetic field. Energetic particles rushed through the gap, penetrating deeply enough for pink.
https://spaceweather.com/

ramnath@nerdpol.ch

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#CME' SPARKS #AURORAS OVER #ICELAND: Every day the sun hurls multiple CMEs into space. Many are faint; some overlap; they go in all directions. It's inevitable that space weather forecasters lose track of some of them. On Sept. 26th, one of those "lost CMEs" hit Earth, sparking this display over Iceland:

"Lying on the ground, looking directly up and seeing the auroras right above me was just incredible!" says photographer Wil Cheung.

No one knows where the instigating CME came from.

https://spaceweather.com/