Photographers consider themselves lucky when they catch a green flash. The sunset emerald ray is so rare, it was once thought to be a fable. Now imagine the odds of catching a triple green flash. James W. Young did it last night while standing on Oregon's Cannon Beach:

"The setting sun produced a green flash which split into three layers," marvels Young. "I photographed them using a 1120mm telephoto lens with a Canon 1Dx Mark II camera."
This is a sign of very strong temperature inversions (warm air above cold) over the Pacific Ocean. Strong inversions produce 'ducts'. Rays from the setting sun get trapped in these ducts, bouncing up and down and traveling long distances in layers sometimes only a few inches thick. A trio of ducts split the green flash into a stack of three. You can actually see the ducts edge-on in Young's picture--a marvel, indeed.
https://spaceweather.com/

September 20, 2021 / Dr.Tony Phillips - NASA

Sept. 24, 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 source of these auroras,” says UCLA space physicist Xu Zhang, lead author of papers reporting the results in the Journal of Geophysical Research: Space Physics and Physics of Plasmas.

It is Earth itself.

Earth performs this trick using electron beams. High above our planet’s poles, beams of negatively-charged particles shoot upward into space, accelerated by electric fields in Earth’s magnetosphere. Sounding rockets and satellites discovered the beams decades ago. It turns out, they can power the diffuse auroras.

The video below shows how it works. The beams travel in great arcs through the space near Earth. As they go, they excite ripples in the magnetosphere called Electron Cyclotron Harmonic (ECH) waves. Turn up the volume and listen to the waves recorded by THEMIS-ARTEMIS:

Above: A great electrical circuit in space powering diffuse auroras. ECH waves were sonified by NASA’s HARP (Heliophysics Audified: Resonances in Plasmas) software.

ECH waves, in turn, knock other electrons out of their orbits, forcing them to fall back down onto the atmosphere. This rain of secondary electrons powers the diffuse auroras.

“This is exciting,” says UCLA professor Vassilis Angelopoulos, a co-author of the papers and lead of the THEMIS-ARTEMIS mission. “We have found a totally new way that particle energy can be transferred from Earth’s own atmosphere out to the magnetosphere and back again, creating a giant feedback loop in space.”

According to Angelopoulos, Earth’s polar electron beams1 sometimes weaken but they never completely go away2, not even during periods of low solar activity. This means Earth can make auroras without solar storms.

The sun is currently experiencing periods of quiet as young Solar Cycle 25 sputters to life. Pea soup, anyone?  [Note: Solar Cycle 25 is accelerating.  MS}

End Notes:

(1) Why do these electron beams exist? Earth’s magnetosphere is buzzing with energetic particles. Many of them are captured from the solar wind. When these particles strike the top of Earth’s atmosphere (the ionosphere), they dislodge electrons. Electric fields, which form naturally in Earth’s spinning magnetosphere, grab the liberated electrons and accelerate them skyward in collimated beams.

(2) Why don’t the beams ever go away? Short answer: because the solar wind never stops blowing. Even when the sun is quiet, Earth’s magnetosphere is jostled and energized by the ever-present solar wind. As a result, electrons are always being knocked off the top of Earth’s atmosphere as described in Note #1. Although solar storms are not required for this process, solar storms can help. For instance, when a CME strikes Earth’s magnetosphere, the contents of the magnetosphere become extra-energized. Lots of particles furiously strike the top of Earth’s atmosphere, liberating even more electrons than usual. Earth’s electron beams can thus become super-charged. When the storm subsides, the electron beams may weaken, but they never vanish because even the quiet sun produces solar wind.

References:

Zhang, X., Angelopoulos, V., Artemyev, A. V., Zhang, X.-J. (2021), Beam-driven ECH waves: A parametric study, Phys. Plasmas, 28, 072902, https://doi.org/10.1063/5.0053187

Zhang, X., Angelopoulos, V., Artemyev, A. V., Zhang, X.‐J., Liu, J. (2021). Beam‐driven electron cyclotron harmonic waves in Earth’s magnetotail. Journal of Geophysical Research: Space Physics, 126, e2020JA028743. https://doi.org/10.1029/2020JA028743s

https://spaceweatherarchive.com/2021/09/20/earth-can-makes-its-own-auroras/

Solar Cycle 25 continues to overperform. Sunspot counts for Sept. 2021 were the highest in more than 5 years. And, for the 11th month in a row, the sunspot number has significantly exceeded the official forecast.

The plot above shows sunspot counts vs. time. The red curve traces the forecast issued by the NOAA/NASA Solar Cycle 25 Prediction Panel in 2019. It calls for a relatively weak solar cycle peaking in July 2025.
The sun has a mind of its own, though. Higher-than-expected sunspot counts suggest a stronger cycle, with a peak occurring in late 2024 instead of mid-2025. This is good news for aurora watchers, but maybe not so good for the Internet.
https://spaceweather.com/

You don't see this every day, especially not in Florida. On April 23rd, a pair of glowing V's appeared above the setting sun, both caused by ice crystals in the air. Dan Gore photographed them from Viera, FL:

"They lingered for about 5 minutes, then they were gone," says Gore. "It was a beautiful sight."
These are sun halos, one rare and one common. The lower 'V' is a common upper tangent arc created by sunlight shining through pencil-shaped ice crystals. The upper 'V' is a rare Parry arc created by similar kinds of ice crystals, but... To make the Parry arc, the crystals had to be horizontal, not rotate, and have two faces horizontal, too. It sounds improbable, and it is. That's why the Parry arc is so rare.
What's all this ice doing in Florida air? The crystals were located in cirrus clouds 5 to 10 km above the ground where the air is always freezing--even in Florida. Parry arcs prefer cold climates, but they can appear in the Sunshine State, too.
www.spaceweather.com

Earth's orbit around the sun isn't a perfect circle, it's an ellipse. One side is closer to the sun (147.5 million km) than the other (152.6 million km). This weekend (Jan. 2nd), we're at the closest point, known to astronomers as perihelion. When Earth is at perihelion, the sun looks a little bigger than usual, as shown in this composite image from Khosro Jafarizadeh of Karaj, Alborz, Iran:

Jafarizadeh took the two pictures from opposite ends of Earth's orbit: perihelion and aphelion. Sunlight falling on Earth at perihelion is 3.5% stronger than the year-long average. Northern snow doesn't melt, however, because seasons are shaped primarily by the tilt of Earth's spin axis, not the eccentricity of its orbit.
www.spaceweather.com

In Iceland, the New Year began with a very special sunrise. "Just before the sun appeared on Jan. 1st, a pink shaft of light sprung up from the eastern horizon," says Wioleta Gorecka, who sends this picture from the port of Hafnarfjordur: "What a beautiful way to greet 2021," she says.

This is a sun pillar, caused by plate-shaped ice crystals fluttering like leaves in distant cirrus clouds. The crystals intercept sunbeams, bending and reflecting them into a tall column of light. Look for pillars around sunrise and sunset; they are especially easy to find in cold places like Iceland where icy clouds bookend the short days of winter.
www.spaceweather.com

A sunspot is emerging in the sun's northern hemisphere. Its magnetic polarity identifies it as a probable member of new Solar Cycle 25. This is the second Solar Cycle 25 sunspot we've seen this month, continuing a trend of low but intensifying Cycle 25 activity. The next solar cycle is coming, after all.

Solar Minimum is having a calming effect on Earth's magnetic field. The deepening quiet is shown in these geomagnetic data, taken by Stuart Green of Preston, Lancashire, UK, during each of the past 3 summers:

"I've plotted the changing levels of geomagnetic activity for the months of May, June and July (between the equinoxes) for the years 2017, 2018 and 2019," explains Green, who operates a research-grade magnetometer buried in his backyard. "The trend is clearly downward, with less frequent and intense storms in 2019, as the sun continues deeper into Solar Minimum."
His data show why minor G1-class geomagnetic storms, which would rarely be mentioned during Solar Maximum, are suddenly noteworthy. Any magnetic storm is news at this point in the solar cycle.
The quiet won't last forever, though. A panel led by experts from NOAA and NASA predict that the solar cycle will bottom out in late 2019 with a bounce back to higher levels of activity beginning sometime in 2020. Meanwhile, G1 is a significant magnetic storm.
www.spaceweather.com

A minor interplanetary shock wave hit Earth on May 26th at approximately 22:00 UT. The CME-like disturbance was unexpected. It caused the density of the solar wind around Earth to abruptly quadruple, while the interplanetary magnetic field doubled in strength. Minor geomagnetic storms are possible on May 27th as our planet passes through the shock wave's wake.
www.spaceweather.com

Ski resorts are one of the best places to see sun halos--rings of light that surround the sun when ice crystals fill the air. Spaceweather.com reader Julie Morris was skiing at the Snowbasin Resort in Huntsville, Utah, on Nov. 25th when she witnessed this incredible specimen:

"I had never seen anything like it," says Morris. "It lasted for more than 15 minutes, and other skiers stopped to photograph it as well. I was so glad that my iPhone photo turned out because my hands were numb and I also couldn't see that well because I had stared at the brightness for so long!"
Ordinary sun halos are caused by ice crystals floating high above Earth's surface in cirrus clouds. "Ski halos," on the other hand, are formed by ice crystals near the ground, kicked into the air by the action of skis and snow-making machines.

"There were snow-making machines in operation at the time," says Morris. That's important because snow-making machines produce a very special type of ice. Crystals called "diamond dust" grow slowly downwind of ski-slope snow blowers. These man-made crystals tend to be more optically perfect than natural crystals in clouds, producing extra-bright, extra-sharp halos.
Morris's quick iPhone photo captured a rare variety of forms: a 22-degree halo, sundogs, sub-sundogs, a sub-sun, a lower sun pillar, an upper tangent arc, a supralateral arc, a Parry arc, a 46-degree halo, a circumzenithal arc, and a parhelic circle--all sculpted from sunlight by floating diamond dust.
www.spaceweather.com

Over the weekend, a small sunspot materialized in the sun's northern hemisphere, then, hours later, vanished again. Such an occurrence is hardly unusual during solar minimum when sunspots are naturally small and short-lived. However, this ephemeral spot was noteworthy because its magnetic field was reversed--marking it as a member of the next solar cycle.

Shown above is a magnetic map of the sun from NASA's Solar Dynamics Observatory on Nov. 17th. Two sunspot groups visible at 21:00 UT are inset.

Note sunspot AR2727 just north of the sun's equator. It is a member of decaying Solar Cycle 24, the cycle that peaked back in 2012-2014. Next, compare its magnetic polarity to that of the other, unnumbered sunspot high above it. They are opposite. According to Hale's Law, this means the two sunspots belong to different solar cycles. The high latitude sunspot appears to be a harbinger of Solar Cycle 25.

Solar cycles always mix together at their boundaries. Indeed, ephemeral sunspots possibly belonging to Solar Cycle 25 have already been reported on Dec. 20, 2016, and April 8, 2018. Now we can add Nov. 17, 2018, to list. The slow transition between Solar Cycle 24 and Solar Cycle 25 appears to be underway.

What does this mean? First, it suggests that the solar cycle is still operative. This contradicts widespread internet buzz that a Grand Minimum is in the offing, with no new sunspots expected for decades as the solar cycle grinds to a halt. Second, if patterns of previous solar cycles hold, Solar Minimum is not finished. It will probably continue to deepen in the year or so ahead even as new Solar Cycle 25 sunspots occasionally pop up, promising an ultimate end to the lassitude.
www.spaceweather.com

Last weekend, Nov. 10th, a stream of fast-moving solar wind hit Earth's magnetic field, igniting a ring of auroras around the South Pole. Minoru Yoneto saw the red-purple glow all the way from Queenstown, New Zealand:

"We were lucky to catch another Southern Lights display during my stargazing tour," says Yoneta. "Our guests were excited to photograph them using their own cameras."

Queenstown is at 45 degrees south latitude--a considerable distance from the South Pole. That's why the auroras looked red. Auroras circling the South Pole must reach very high above Earth's surface to be visible half a hemisphere away. At altitudes greater than ~200 km, auroras turn red. The ruby glow occurs when high energy particles from space hit oxygen atoms at the top of the atmosphere. Ionized molecular nitrogen adds a dash of purple to the high-altitude palette.

More red Southern Lights are possible on Nov. 18th or 19th when a new stream of solar wind is expected to arrive. The gaseous material is flowing from a relatively small hole in the sun's atmosphere. Queenstown stargazers, charge your cameras!
www.spaceweather.com

The Parker Solar Probe has just radioed NASA with good news. The spacecraft survived its close approach to the sun on Nov. 5th. Because the sun is a giant natural source of broadband radio noise, Parker cannot transmit complicated data streams through the interference. Images and data won't arrive until early December when the probe has reached a sufficient distance from the sun again. For now, mission controllers are happy to have received a simple beacon saying the spacecraft is okay.

Earlier this week, Parker screamed around the sun at 213,200 mph only 15 million miles from the stellar surface--shattering old records for both speed and distance. Intense sunlight raised the temperature of the probe's heat shield to about 820 degrees Fahrenheit. All the while, instruments and systems behind the shield kept cool in the mid-80s F.

Mission controllers at the Johns Hopkins University Applied Physics Lab received the status beacon at 4:46 p.m. EST on Nov. 7, 2018. It indicated, simply, "A" — the best of all four possible status signals, meaning that the probe is operating well with all instruments running and collecting science data and, if there were any minor issues, they were resolved autonomously by the spacecraft. Stay tuned for "first light" science results about one month from now.
www.spaceweather.com