A new type of aurora is rippling across Arctic skies. Citizen scientists who discovered it nicknamed it "The Dunes" because of its resemblance to desert sand dunes. A paper published in the Jan. 28th issue of AGU Advances describes the new form and the unexpected physics that causes it.

Dune-shaped auroras form in a narrow altitude range 80 km to 120 km above Earth's surface. Turns out, this is an extremely hard-to-study layer of Earth's atmosphere. It's too high for weather balloons, and too low for rockets.

"Due to the difficulties in measuring atmospheric phenomena between 80 and 120 km, we sometimes call this region 'the ignorosphere'," says Minna Palmroth, Professor of Computational Space Physics at the University of Helsinki and the lead author of the study.

Sky watchers in the Arctic have been seeing Dunes for years without understanding what they were. A breakthrough came on Oct. 7, 2018, when multiple groups photographed the dunes from widely separated locations in Finland. Maxime Grandin, a postdoctoral researcher in Palmroth's team, analyzed the images, using triangulation techniques to decipher the Dune's geometry.

Conclusion: Dunes are located ~100 km high--smack-dab in the middle of the ignorosphere--and have a pure, monochromatic wavelength of about 45 km.

Above: An artists' concept of a mesospheric bore trapped in a high-altitude waveguide. [more]

The research team believes the Dunes are a "mesospheric bore"--a type of atmospheric gravity wave that springs up from the surface below and gets caught in a thermal waveguide ~100 km high. When solar wind particles rain down on the bore, they illuminate its rippling structure.

The discovery of Dunes may allow researchers to study the ignorosphere as never before. Monitoring Dunes can reveal previously hidden waves and waveguides at the boundary between Earth and space. Aurora photographers, have you seen a Dune? Submit your photos here.
www.spaceweather.com

Emily McPherson, 9news.com.au
Wed, 08 Jan 2020

Beautiful photographs of the bush regrowing on the NSW Central Coast a month after fires devastated the region have been picked up as a symbol of hope online.

Local photographer Murray Lowe snapped the shots in the Kulnara area on Monday and posted them on Facebook, where they have been shared more 37,000 times in less than 48 hours.

"Ventured out into the fire grounds today to capture some images of how the Aussie bush responds to fire, and the way it regenerates itself and comes back to life," Mr Lowe wrote in his post.

"Even without any rain, life bursts through the burnt bark from the heart of the trees and the life cycle begins again."

Mr Lowe urged as many people as possible to share the photos.

"It's so heartening to see the bush coming back to life again," he wrote.

Other Facebook users also shared their photos of the bush regenerating near their homes in the comments section of Mr Lowe's post.

In an update to the post, Mr Lowe said he had been blown away by the response to his photos.

"I did not, in my wildest dreams, anticipate the overwhelming response to my photos that I've seen. It's both humbling, and heart-warming," he wrote.

Port Macquarie Koala Hospital, which has been faced with the desperate task of saving our decimated koala population, also recently shared an image showing regrowth on the "trunks of koala food" in the Bril Bril state forest.

"To live in the world without becoming aware of the meaning of the world is like wandering about in a great library without touching the books."

- Manly P. Hall, author of 'The Secret Teachings of All Ages'

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

Denise Piper, Stuff.nz, 03 Jul 2019

A team of international scientists believe they have found the answers to the mysteries of Earth's last polar reversal in the tree rings of an ancient kauri. The 20 metre-long kauri log could map out what to expect during a geomagnetic reversal - a change in the planet's magnetic field - including its impact on climate change and solar radiation.

The kauri, measuring a massive 2.5m in diameter, is one of the oldest trees ever found. The ancient kauri tree was uncovered during excavations Northland's Ngāwhā about three months ago during excavations for a geothermal power plant expansion. The tree was buried in about 8m of soil and was preserved like swamp kauri, despite not actually being in a swamp. Now, carbon dating has confirmed the ancient kauri was alive 41,000 to 42,500 years ago, making it one of the oldest trees ever found.

"This Ngāwhā kauri is unique in the world," University of Waikato associate professor Alan Hogg, the director of the Waikato Radiocarbon Dating laboratory, said. During its 1500-year lifespan, the tree experienced one of the earth's geomagnetic excursions, meaning the north magnetic pole drifted down to the southern hemisphere and back up again. "There's nothing like this anywhere in the world."

While knowledge of the geomagnetic excursion was not new, a tree that spanned the entire excursion timeframe had never been found, Hogg said. "It's the time it takes for this movement to occur that is the critical thing ... We will map these changes much more accurately using the tree rings," he said. Study of the ancient tree has just begun but Hogg said it would give a picture of the solar radiation in the earth's atmosphere during the excursion.

As the magnetic poles moved, the strength of earth's geomagnetic field weakened, letting in more cosmic radiation, he said. And the tree would show what to expect during another polar excursion or reversal - which scientists said was not a matter of if, but when. "We will have increased cosmic radiation. It will take out satellites and it might take out other communication infrastructure," Hogg said.

Ngāwhā Generation - a subsidary of Northland power wholesaler Top Energy - gave the kauri tree back to iwi on the agreement scientists could take samples for study.

The research is being funded by the Australia Research Council and led by Professor Chris Turney from the University of New South Wales, a expert in paleoclimatology and climate change over the past 40,000 years.

MIT Technology Review; Fri, 21 Jun 2019 18:43 UTC

The Tibetan Plateau is a vast elevated plain almost five kilometers above sea level, sometimes called the Roof of the World. It is bordered to the south by the world's highest mountain range and to the north by desert lands. It is one of the most isolated places on Earth.

But the extreme altitude makes it a useful place for scientists. In 1990, they built an observatory here to study the showers of subatomic particles that rain down from the upper atmosphere whenever it is hit by a high-energy cosmic ray. This work is better done at high altitude because there is less atmosphere to absorb the particles.

Since then, the so-called Tibet Air Shower Array has recorded vast numbers of high-energy cosmic rays, particles accelerated to huge energies by astrophysical phenomena such as supernovas, active galactic nuclei, and mysterious as-yet-unidentified sources.

But the array also picks up air showers caused by a different source - high-energy photons. These mysterious photons are also created by astrophysical phenomena such as the interaction between high-energy particles and the cosmic microwave background. Consequently, they can provide a unique insight into these processes and the environments in which they occur.

Over the years, the Tibet Air Shower Array has spotted plenty of these photons with energies up to dozens of teraelectronvolts (TeV 1012). That's roughly equivalent to the highest-energy photons that can be created on Earth. But nobody has ever observed more powerful photons.

Until now. Today, researchers from the Tibet Air Shower Gamma Collaboration say they have observed photons with energies above 100 TeV for the first time, including a remarkable photon with an energy of almost 500 TeV. This single photon has about the same energy as a falling Ping-Pong ball and is the highest-energy photon ever recorded.

The collaboration has also worked out where these photons are coming from: the Crab Nebula, the remnants of a supernova that occurred in 1054 AD in the Perseus Arm of the Milky Way, some 6,500 light-years from Earth.

.... read more at https://www.sott.net/article/415559-Earth-hit-by-highest-energy-photons-ever-recorded-from-the-Crab-Nebula

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

David Claughton and Olivia Ralph; abc.net.au; 10 Mar 2019

Boorowa farmer Charlie Arnott has experienced the immense toll of drought on his cattle, his business and his wellbeing, but he has found a way through it all. Fifteen years ago, reeling from the effects of the Millennium drought, he attended a workshop on regenerative agriculture that radically changed the way he farmed and, he believes, saved his life. "I was doing a really good job of killing a lot of stuff to try and grow food, which is kind of crazy," Mr Arnott said.

He had been farming conventionally using pesticides, herbicides and fertilisers, but the course taught him how to partner with nature instead of trying to control it. It has turned around his farm's capacity to deal with drought and he currently has plenty of water and grass for his livestock even as the drought in NSW intensifies.

"We haven't fed for 15 years [because] we measure how much grass we have, we know how many animals we have to eat that grass and a very simple calculation gives us the amount of time that that grass is available before it runs out," Mr Arnott said.

From a desert to a paradise

Another farmer in Boorowa, David Marsh, began his journey into regenerative agriculture in the 1980s, after a drought brought him to the edge of ruin. "In 1982 we reduced our numbers far too late, like so many ... and we turned this place into a desert," Mr Marsh said.

"In that time you couldn't give sheep away and I promised I wouldn't do that again."

He began adopting regenerative practices in 1999, increasing the amount of native vegetation and tree coverage on his property from just 3 per cent to 20 per cent.

The rest of this article can be read here: https://www.sott.net/article/409672-From-a-desert-to-a-paradise-Regenerative-agriculture-finds-solid-backing-as-decades-of-success-show-renewal

When a stream of solar wind hits Earth's magnetic field, magnetometers around the Arctic Circle normally go a bit haywire, with their needles swinging chaotically as the buffeting ensues. Rob Stammes of the Polarlightcenter, a magnetic observatory in Norway, sees such disordered behavior all the time. But on Nov. 18th something quite different happened. The solar wind produced a pure sine wave:

"A very stable ~15 second magnetic oscillation appeared in my recordings, and lasted for several hours," he says. "The magnetic field was swinging back and forth by 0.06 degrees, peak to peak."
Imagine blowing across a piece of paper, making it flutter with your breath. The solar wind can have a similar effect Earth's magnetic field. The waves Stammes recorded are essentially flutters propagating down the flanks of our planet's magnetosphere excited by the breath of the sun. Researchers call them "pulsations continuous" -- or "Pc" for short..
"A sensitive magnetometer is required to record these waves," says Stammes. "I use a mechanical magnetometer with bar magnets suspended from a special wire. LEDs and light detectors in an isolated dark box record the motion of the magnets, while vanes in oil damp out non-magnetic interference."
Pc waves are classified into 5 types depending on their period. The Nov. 18th waves fall into category Pc3. Researchers have found that Pc3 waves sometimes flow around Earth's magnetic field and cause a "tearing instability" in our planet's magnetic tail. This, in turn, sets the stage for an explosion as magnetic fields in the tail reconnect.

A quartet of NASA spacecraft recently flew through just such an explosion. Last week, researchers from the University of New Hampshire reported that four Magnetospheric Multiscale (MMS) spacecraft spent several seconds inside a magnetic reconnection event as they were orbiting through Earth's magnetic tail. Sensors on the spacecraft recorded jets of high energy particles emerging from the blast site. One jet was aimed squarely at Earth and probably sparked auroras when it hit the upper atmosphere.
Stammes has recorded many Pc waves in the past, "but this is the first time I have detected category Pc3," he says. "This was a very rare episode indeed."
www.spaceweather.com

Laura Geggel; Live Science; Wed, 07 Nov 2018 09:34 UTC

An eerie, marmalade-colored light show made Earth look like a gigantic orange lollipop, prompting an astronaut aboard the International Space Station to snap a photo of it on Oct. 7. And yesterday, NASA shared the glorious shot with Earthlings down below.

The enveloping orange hue is known as airglow - a mesmerizing luminescence caused by chemical reactions high in Earth's atmosphere, NASA reported. This ghostly glow usually happens when ultraviolet radiation from sunlight energizes molecules of nitrogen, oxygen, sodium and ozone in the atmosphere. These energized molecules then bump into each other and lose energy as they collide, resulting in a faint but spectacular afterglow, NASA said.

Airglow is best seen at night, as it's 1 billion times fainter than sunlight, NASA said. This particular photo was taken at an altitude of more than 250 miles (about 400 kilometers) above Australia.

The radiating blush, also known as chemiluminescence, is comparable to glowing chemical reactions here on Earth, including those seen in children's toys such as glow sticks and glow-in-the-dark silly putty, NASA added.

But airglow is more than an entrancing light attraction. It can also teach scientists about the workings of the upper atmosphere. For instance, it can shed light on how particles near the interface of Earth and space move, including how space weather and Earth weather are connected, NASA said.

Researchers are already using satellites - such as NASA's Ionospheric Connection Explorer (ICON) - to study this dynamic zone.

Although this airglow emanated orange, the phenomenon isn't always the color of the snack food Doritos. In 2016, a photographer in the Azores islands in the Atlantic Ocean took a photo of a rainbow-colored airglow, according to Space.com, a sister site of Live Science.

On Oct. 26th, Venus will pass almost directly between Earth and the sun--an event astronomers call "inferior solar conjunction." As Venus approaches the sun, the planet is turning its night side toward Earth, reducing its luminous glow to a thin sliver. Shahrin Ahmad of Kuala Lumpur, Malaysia, took this picture on Oct. 20th:

"I took this picture in broad daylight," says Ahmad. "Venus was really big in the eyepiece of my telescope--almost a full arcminute in diameter. And the crescent shape easily visible in the 8x50 finder scope."
In the days ahead, the crescent of Venus will become increasingly thin and circular. The horns of the crescent might actually touch when the Venus-sun angle is least (~6 degrees) on Oct. 26th. This is arguably the most beautiful time to observe Venus, but also the most perilous. The glare of the nearby sun magnified by a telescope can damage the eyes of anyone looking through the eyepiece.
Anthony J. Cook of the Griffith Observatory has some advice for observers: "I have observed Venus at conjunction, but only from within the shadow of a building, or by adding a mask to the front end of the telescope to fully shadow the optics from direct sunlight. This is tricky with a refractor or a catadioptric, because the optics start at the front end of the tube. Here at Griffith Observatory, I rotate the telescope dome to make sure the lens of the telescope is shaded from direct sunlight, even through it means that the lens will be partially blocked when aimed at Venus. With our Newtonian telescope, I add a curved cardboard mask at the front end of the tube to shadow the primary mirror."
For the rest of this week Venus can still be observed without elaborate precautions in deep twilight after sunset. Every evening the crescent grows and narrows. Scan the realtime photo gallery for updates.
www.spaceweather.com

The sun is entering a deep Solar Minimum, and Earth's upper atmosphere is responding. Data from NASA's TIMED satellite show that the thermosphere (the uppermost layer of air around our planet) is cooling and shrinking, literally decreasing the radius of the atmosphere. If current trends continue, the thermosphere could set a Space Age record for cold in the months ahead: Full story.
www.spaceweather.co