What goes up, must come down--which could be a problem when you're launching thousands of satellites. Since 2018, SpaceX has placed more than 7,000 Starlink satellites into Earth orbit, and now they are starting to come down. In January alone, more than 120 Starlinks deorbited, creating a shower of fireballs."The sustained rate of daily reentries is unprecedented," says Jonathan McDowell, an astronomer at the Harvard Center for Astrophysics who tracks satellites. "They are retiring and incinerating about 4 or 5 Starlinks every day."

Planners have long known this would happen. First generation (Gen1) Starlink satellites are being retired to make way for newer models. "More than 500 of the 4700 Gen1 Starlinks have now reentered," says McDowell.
When Starlinks reenter, they disintegrate before hitting the ground, adding metallic vapors to the atmosphere. A study published in 2023 found evidence of the lingering devris. In February 2023, NASA flew a WB-57 aircraft 60,000 feet over Alaska to collect aerosols. 10% of the particles contained aluminum and other metals from the "burn-up" of satellites.

What we're observing is a giant uncontrolled experiment in atmospheric chemistry. The demise of just one Gen1 Starlink satellite produces about 30 kilograms (66 pounds) of aluminum oxide, a compound that eats away at the ozone layer. A new study finds these oxides have increased 8-fold between 2016 and 2022, and the recent surge is increasing the pollution even more.
On the bright side, each reentry produces a beautiful fireball--and the odds are increasing that you'll see one. Visit the Aerospace Corporation for reentry predictions.
https://spaceweather.com/

Something interesting is happening in the polar stratosphere. A 40-year cold spell is underway, and the temperature continues to drop. We know its cold because the stratosphere is starting to fill with colorful clouds. They look like this:

These are Type II polar stratospheric clouds (PSCs) photographed by Per Steinar Prøven of Brumunddal, Norway. "We have been seeing them day and night," he says.
Polar stratospheric clouds are rare. Normally, the stratosphere has no clouds at all. When the temperature drops to -85 C (188 K), however, water molecules can get together to form ice crystals even in the very dry stratosphere. High-altitude sunlight touching those crystals creates a blossom of pastel color.
According to NASA's MERRA2 climate model, temperatures in the polar stratosphere are about to drop to their lowest levels since before 1978. This could cause a major outbreak of polar stratospheric clouds, visible around the Arctic Circle and beyond.
https://spaceweather.com/

In a joint statement on Oct. 15th, NASA and NOAA announced that Solar Maximum is underway. If you saw last week's geomagnetic storm, you probably reached the same conclusion. Good news: Solar Max is not a narrow moment in time; it is a lengthy phase of solar activity that can last for 2 or 3 years. More aurora outbursts are likely in 2024 and 2025. Listen to the press conference here.
https://spaceweather.com/

New sunspot AR3825 erupted again today, producing a very strong X4.5-class solar flare. NASA's Solar Dynamics Observatory recorded the extreme ultraviolet flash:

Radiation from the flare ionized the top of Earth's atmosphere, resulting in a deep shortwave radio blackout over South America and the mid-Atlantic Ocean: map. Ham radio operators and mariners may have noticed loss of signal at frequencies below 30 MHz for as much as 30 minutes after the flare's peak (1529 UTC).

A CME is emerging from the blast site, but it is too soon to say whether it has an Earth-directed component. Stay tuned for updates. Solar flare alerts: SMS Text

more images: from Warren Spreng of Mason, Ohio
https://spaceweather.com/

Active sunspot AR3777 just produced its most powerful solar flare yet--an X1.3-class explosion on Aug. 8th (1935 UT). NASA's Solar Dynamics Observatory recorded the extreme ultraviolet flash:

Radiation from the flare ionized the top of Earth's atmosphere and caused a shortwave radio blackout from North America to the Hawaiian islands. Mariners and ham radio operators may have noticed loss of signal below 30 MHz for as much as an hour after the flare.
Of greater interest is a possible CME. The US Air Force is reporting a strong Type II radio burst. This type of natural radio emission comes from shock waves at the leading edge of a fast CME. Confirmation awaits fresh data from SOHO coronagraphs. Stay tuned.
https://spaceweather.com/

The night sky is about to get a new star. Sometime this summer, astronomers believe, a nova will explode in the constellation Corona Borealis (the Northern Crown). The exploding star will be bright enough to see with the naked eye even from light-polluted cities.

"It’s a once-in-a-lifetime event," says Rebekah Hounsell of NASA’s Goddard Space Flight Center. "I believe it will create a lot of new astronomers out there."
T Coronae Borealis (T CrB) is a binary system 3,000 light-years from Earth. It consists of a white dwarf orbiting an ancient red giant. Hydrogen from the red giant is being pulled down onto the surface of the white dwarf, accumulating toward a critical mass. Eventually, it will trigger a thermonuclear explosion.
The last time T CrB exploded was in 1946. About a year before that blast, the system suddenly dimmed--a pattern astronomers called the "pre-eruption dip." In 2023, T CrB dipped again, heralding a new eruption. If the 1946 pattern repeats itself, the nova should occur between now and September 2024.

The outburst will be brief. Once it erupts, the nova will be visible to the naked eye for a little less than a week – but Hounsell is confident it will be quite a sight to see. The expected magnitude is between +2 and +3, similar to stars in the Big Dipper.
"Typically, nova events are faint and far away," says Elizabeth Hays, chief of the Astroparticle Physics Laboratory at NASA Goddard. "This one will be really close, with a lot of eyes on it. We can’t wait to get the full picture of what's going on."
https://spaceweather.com/

A new source of solar flares is emerging over the sun's southeastern limb. On May 15th (1438 UT), it emitted a dramatic X3-class explosion, shown here in a movie from NASA's Solar Dynamics Observatory:

Extreme ultraviolet radiation from the flare ionized the top of Earth's atmosphere, causing a shortwave radio blackout over the Atlantic Ocean. Ham radio operators, aviators and mariners may have noticed a sudden loss of signal at all frequencies below 30 MHz.
The source of this flare will rotate over the sun's limb this week, making future explosions more squarely Earth-directed and potentially hurling CMEs in our direction. Stay tuned!
https://spaceweather.com/

Sunspot AR3664 just unleashed the strongest solar flare of the current solar cycle--an X8.7-category blast from beyond the sun's western limb. X marks the spot in this image of the flare from NASA's Solar Dynamics Observatory:

Because the sunspot is behind the edge of the solar disk, the flare was partially eclipsed. It was probably even stronger than it appeared. "X8.7" is almost certainly an underestimate of the flare's true strength.
Extreme ultraviolet radiation from the flare ionized the top of Earth's atmosphere, causing a deep shortwave radio blackout over the Americas. Ham radio operators, aviators and mariners may have noticed a sudden loss of signal at all frequencies below 30 MHz.
Subatomic debris from this event might soon reach Earth, guided toward our planet by the Parker Spiral. Also, a CME might be in the offing. Stay tuned for updates!
https://spaceweather.com/

Giant sunspot AR3664 unleashed another X-flare today (May 11th @ 0139 UT)--its strongest yet. NASA's Solar Dynamics Observatory captured a bright ultravolet flash from the category X5.8 explosion:

Radiation from the flare caused a deep shortwave radio blackout over the Pacific Ocean. Ham radio operators and mariners may have noticed loss of signal at frequencies below 30 MHz for as much as an hour after the flare's peak.
We don't yet know if this flare hurled a CME into space. If it did, it could have a grazing Earth-directed component. Confirmation awaits fresh data from SOHO coronagraphs.
https://spaceweather.com/

Yesterday (9 February) at 13.14 UT, the sun produced one of the most powerful solar flares in years, an X3.4-class explosion from just behind the sun's southwestern limb. NASA's Solar Dynamics Observatory (SDO) recorded the extreme ultraviolet flash:

The source of the flare appears to be departing sunspot AR3575. Because the blast site was eclipsed by the edge of the sun, the flare was probably even stronger than its X3.4 classification suggests. This was a big explosion.
Hours after the flare's peak, Earth was still feeling the effects of the blast. Solar protons energized by the flare are following curved magnetic field lines from the sunspot back to our planet. The resulting hailstorm, called a "radiation storm," is still intensifying at the time of this writing (9 February) and has just reached category S2:

This plot shows what NOAA's GOES-18 satellite is seeing right now. The colored lines count the number of energetic protons streaming past the satellite en route to Earth. Green and blue are of special interest because they trace "hard protons" capable of upsetting spacecraft electronics, e.g., causing reboots of onboard computers and temporarily fogging cameras.
The explosion also hurled a bright CME into space. It will not hit Earth. Instead, a NASA model of the CME shows it is heading for Mercury, Venus and Mars. It will hit all three planets this weekend.

10 February 2024:
For the second day in a row, energetic protons from the sun are raining down on Earth. This is called a "solar radiation storm," and it is currently a category S2 event. A data-plot from NOAA's GOES-18 satellite shows how protons surged around our planet just after yesterday's X-class solar flare:

The colored lines count the number of energetic protons streaming past GOES-18 en route to Earth. Green and blue are of special interest because they trace "hard protons" capable of upsetting spacecraft electronics, e.g., causing reboots of onboard computers. These particles can even reach all the way down to aviation altitudes, boosting dose rates for passengers and crews flying commercial planes over Earth's polar regions.
We can actually *see* some of these protons. Take a look at this SOHO coronagraph movie of the sun hours after the flare:

The "snow" in this movie is caused by the radiation storm. Each speckle is a solar proton striking the spacecraft's digital camera. This is a good example of how radiation storms can temporarily interfere with orbital imaging systems.

Another effect of the radiation storm is an ongoing blackout of shortwave radio transmissions around Earth's poles. This is called a "polar cap absorption event". Earth's magnetic field is guiding many of the incoming protons towards the poles, where they ionize the upper atmosphere; this, in turn, wipes out radio signals below 30 MHz. Many shortwave radios inside the Arctic Circle simply won't work until the radiation storm is over.
https://spaceweather.com

Recent measurements by NASA's Solar Dynamic Observatory reveal a rapid weakening of magnetic fields in the polar regions of the sun. North and south magnetic poles are on the verge of disappearing. This will lead to a complete reversal of the sun's global magnetic field perhaps before the end of the year.

If this was happening on Earth there would be widespread alarm. Past reversals of our planet's magnetic field have been linked to calamities ranging from sudden climate change to the extinction of the Neanderthals. On the sun, it's not so bad.
"In fact, it's routine", says Todd Hoeksema, a solar physicist at Stanford University. "This happens every 11 years (more or less) when we're on the verge of Solar Maximum."
Vanishing poles and magnetic reversals have been observed around Solar Max in every single solar cycle since astronomers learned to measure magnetic fields on the sun.  Hoeksema is the director of Stanford's Wilcox Solar Observatory (WSO), that is observing its fifth reversal since 1980.

"One thing we have learned from these decades of data is that no two polar field reversals are alike," he says.
Sometimes the transition is swift, taking only a few months for the poles to vanish and reappear on opposite ends of the sun. Sometimes it takes years, leaving the sun without magnetic poles for an extended period of time.
"Even more strange," says Hoeksema, "sometimes one pole switches before the other, leaving both poles with the same polarity for a while."
Indeed, such a scenario could be playing out now. The sun's south magnetic pole has almost completely vanished, but the north magnetic pole is still hanging on, albeit barely.
How does all this affect us on Earth? One way we feel solar field reversals is via the heliospheric current sheet:

The sun is surrounded by a wavy ring of electricity that the solar wind pulls and stretches all the way out to the edge of the Solar System. This structure is a part of the sun's magnetosphere. During field reversals, the current sheet becomes extra wavy and highly tilted.  As the sun spins, we dip in and out of the steepening undulations. Passages from one side to another can cause geomagnetic storms and auroras.
Most of all, the vanishing of the poles means we're on the verge of Solar Maximum. Solar Cycle 25 is shaping up to be stronger than forecasters expected, and its peak could be relatively intense. Stay tuned for updates!
https://spaceweather.com/

Daily Mail: Wed, 19 Oct 2022 17:47 UTC

The James Webb Space Telescope captured the iconic "Pillars of Creation," huge structures of gas and dust teeming with stars, NASA said Wednesday, and the image is as majestic as one could hope.

The twinkling of thousands of stars illuminates the telescope's first shot of the gigantic gold, copper and brown columns standing in the midst of the cosmos.

At the ends of several pillars are bright red, lava-like spots. "These are ejections from stars that are still forming," only a few hundred thousand years old, NASA said in a statement.

These "young stars periodically shoot out supersonic jets that collide with clouds of material, like these thick pillars," the US space agency added.

The "Pillars of Creation" are located 6,500 light years from Earth, in the Eagle Nebula of our Milky Way galaxy. The pillars were made famous by the Hubble Space Telescope, which first captured them in 1995 and then again in 2014.

But thanks to Webb's infrared capabilities, the newer telescope -- launched into space less than a year ago -- can peer through the opacity of the pillars, revealing many new stars forming.

"By popular demand, we had to do the Pillars of Creation" with Webb, Klaus Pontoppidan, the science program manager at the Space Telescope Science Institute, said Wednesday on Twitter.

STScI operates Webb from Baltimore, Maryland.

"There are just so many stars!" Pontoppidan added.

NASA astrophysicist Amber Straughn summed it up: "The universe is beautiful!" she wrote on Twitter.

The image, covering an area of about eight light years, was taken by Webb's primary imager NIRCam, which captures near-infrared wavelengths -- invisible to the human eye.

The colors of the image have been "translated" into visible light.

According to NASA, the new image "will help researchers revamp their models of star formation by identifying far more precise counts of newly formed stars, along with the quantities of gas and dust in the region."

Operational since July, Webb is the most powerful space telescope ever built, and has already unleashed a raft of unprecedented data. Scientists are hopeful it will herald a new era of discovery.

One of the main goals for the $10-billion telescope is to study the life cycle of stars. Another main research focus is on exoplanets, planets outside Earth's solar system.
https://www.sott.net/article/473446-Iconic-Pillars-of-Creation-captured-in-new-JWST-image

The first pictures from Juno's flyby of Europa on Sept 29th have arrived on Earth, and they are beautiful. At closest approach, the spacecraft was only 219 miles (352 km) above the ocean moon's icy crust, revealing cryovolcanic ridges, strangely curvaceous fractures, and frozen "rafts."

This is only the third close pass in history below 310 miles (500 kilometers) altitude and the closest look at Europa any spacecraft has gotten since Jan. 3, 2000, when NASA’s Galileo spacecraft came within 218 miles (351 kilometers) of the surface.

At closest approach, Juno was directly above a region of chaos terrain called "Annwn Regio" where rafts of ice had previously broken free and re-frozen. Researchers suspect that water from beneath Annwn Regio must be breaking through from time to time. Researchers will be looking carefully at these images to see if anything has changed since Galileo visited 20+ years ago.
www.spaceweather.com

Sept. 24, 2021: Lightning on Earth is getting weirder and weirder. On the evening of Sept. 20th, Puerto Rican photographer Frankie Lucena pointed his Sony A7s camera at an offshore electrical storm. This is what he saw:

“This Gigantic Jet plasma event occurred over a very powerful thunderstorm near the Virgin Islands just ahead of Tropical Storm Peter,” says Lucena.  “I can’t believe I was able to capture such amazing details.”

Indeed, this is one of the best-ever photos of a Gigantic Jet. Sometimes called “Earth’s tallest lightning” because they reach the ionosphere more than 50 miles high, the towering forms were discovered near Taiwan and Puerto Rico in 2001-2002. Since then, only dozens of Gigantic Jets have been photographed. They seem to love storms over water and are famous for surprising passengers onboard commercial aircraft. 

In 2017 and 2018, lightning researcher Oscar van der Velde of the Universitat Politècnica de Catalunya set up high speed cameras on the northern coast of Colombia in a dedicated campaign to capture Gigantic Jets. In three months of observing time he managed to capture only 12. That’s how elusive they are.

“Frankie has photographed a rare Gigantic Jet with ‘carrot’ morphology, first reported by Su et al (2003),” notes van der Velde. “The other, more common type of jet has a ‘tree’ morphology.” Here is a comparison: trees vs. carrots.

“Carrot jets” are remarkable for their internal beads–that is, bright balls of light hundreds of meters wide. Lucena caught dozens of them illuminating the jet’s midsection. They might be places where streamers inside the jet are intersecting, or regions of enhanced heating.

“We don’t know,” says van der Velde. “Gigantic Jets are not easily placed in front of a spectrograph.”

Meanwhile, Lucena is still marveling at what happened. “This is the brightest Gigantic Jet I have ever seen. It was truly remarkable.”

https://spaceweatherarchive.com/2021/09/26/a-gigantic-jet-with-fireballs/

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/