Andromedid Meteor Outburst

Nov. 29, 2021: The Andromedids are back. Over the weekend astronomers reported an outburst of more than 100 faint meteors per hour. “[It was] the strongest outburst of Andromedid meteors ever detected by the Canadian Meteor Orbit Radar (CMOR),” says Peter Brown of the University of Western Ontario. This radar sky map shows a hot spot of meteor activity on Nov. 28th:

The shower’s not over yet. “The current outburst is ongoing and it may be another few days or even a week before the activity ramps down,” says Brown. “These meteors are too faint to see with the naked eye, but they are easy targets for the radar.”

Andromedids are debris from Biela’s Comet, known to historians as “the comet that split in two.” 3D/Biela started to fall apart not long after it was discovered in 1772. It was a double comet when it swung by Earth in 1852, and was never seen again. In 1872 and 1885, thousands of meteors shot out of the constellation Andromeda as Earth passed through Biela’s remains. Chinese records described “stars that fell like rain.”

Above: Andromedids as seen on the night of November 27, 1872 by Amédée Guillemin (Le Ciel, notions d’astronomie, à l’usage des gens du monde et de la jeunesse, 1864 and 1877) [ref]

After that the Andromedids vanished, too. The shower has been weak or absent entirely since the late 19th century. Only a surprise outburst in 2011 signaled that Biela’s debris might still be lurking nearby. This week’s activity is even more promising.

Bill Cooke of NASA’s Meteoroid Environment Office (MEO) is one of several experts who have been modeling Biela’s debris streams, hoping to forecast a return. “Our models generally do not do well in predicting the timing or intensity,” he says. “However, this year our model got the timing roughly correct.” This plot shows current radar data (red dots) vs. predicted debris stream crossings:

According to Cooke’s model, the outburst on Nov. 28th was caused by a stream of dust laid down in 1655–interestingly before the comet fell apart. “We didn’t think the 1655 crossing would produce much of anything,” confesses Cooke. “So the outburst came as a bit of a surprise.”

A team of astronomers led by Paul Wiegert (including Brown) had already predicted a strong naked-eye Andromedid outburst in December 2023. If they are right, the display two years from now could yield as many as 200 bright meteors an hour, surpassing even the Perseids and Geminids. The current outburst is providing new data for their stream models, and could help improve the predictions.

Stay tuned for updates as the shower continues.

Note: The Canadian Meteor Orbit Radar is operated through a cooperative agreement between Western University’s Meteor Physics Group and NASA’s Meteoroid Environment Office.

Surprise: Some Red Auroras are *not* Auroras

Nov. 22, 2021: The biggest geomagnetic storm in years erupted this month when a Cannibal CME slammed into Earth’s magnetic field. Auroras spread as far south as California and New Mexico. Upon closer inspection, however, not all of those lights were auroras. Some were “SARs.”

SARs are pure red arcs of light that ripple across the sky during strong geomagnetic storms. Here’s an example from Finland in 2018:

“The SAR was visible to the naked eye for nearly 30 minutes and, after fading a bit, remained visible to my camera for another hour and a half,” recalls photographer Matti Helin.

On Nov 4, 2021, Earth experienced a veritable SAR storm. “We photographed SARs as far south as the McDonald Observatory in Texas,” reports Jeff Baumgardner of Boston University’s Center for Space Physics. “The bands of light swept over our cameras near Boston, then headed south. We knew something special was going on.”

SARs may look like auroras, but they not the same. Auroras appear when charged particles rain down from space, hitting the atmosphere and causing it to glow like the picture tube of an old color TV.  SARs form differently. They are a sign of heat energy leaking into the upper atmosphere from Earth’s ring current system.

During the storm on Nov. 4th, an all-sky camera in Capital Reef, Utah, caught a really bright one. Play the movie and watch what happens at the 18-second mark:

“It is pretty unusual to see an SAR at this low latitude,” says Asti Bhatt of SRI International. Bhatt operates MANGO, a continent-spanning network of cameras that monitors the sky for unusual phenomena like SARs.

SARs were discovered in 1956 at the beginning of the Space Age. Researchers didn’t know what they were and unwittingly gave them a misleading name: “Stable Auroral Red arcs” or SARs. In fact, SARs are neither stable nor auroras.

“Our group has observed  scores of SARs over the last three solar cycles,” says Baumgardner.  “In 2015 we published a paper describing them.  We found that SARs are ‘stable’ only when compared to very active auroras. When you watch an SAR for an hour or so, it can be quite dynamic.”

Space physicists are keen on SARs because they are linked to Earth’s ring current–a donut-shaped circuit carrying millions of amps around our planet. The ring current skims the orbits of geosynchronous satellites and plays a huge role in determining the severity of geomagnetic storms. Earth is the only rocky planet that has one.

Above: SARs photographed by the Dynamics Explorer-1 satellite in 1982. More

SARs are among the reddest things in the sky, with a monochromatic glow at 6300 Å that comes from atomic oxygen in the upper atmosphere. Unfortunately, the human eye is relatively insensitive to light at this wavelength. SARs are usually so faint that no one notices when they pass overhead. Cameras catch them easily, though. Pro tip for photographers: Use a 6300 Å filter.

“At the peak of a solar cycle we typically see 30 SARs per year near Boston,” says Baumgardner. “We hope this is a start of an active solar cycle with lots more SAR arcs!”

Space Weather and the Russian ASAT Strike

Nov. 16, 2021: Russia just destroyed one of its own satellites. On Nov. 15, 2021, a missile launched from the Plesetsk Cosmodrome struck Kosmos 1408, shattering the old satellite into thousands of pieces. Debris came so close to the ISS that astronauts took shelter in their crew capsules, just in case they had to abandon ship.

Littering Earth orbit with debris is never a good idea. Space weather could make it much worse. To understand why, turn back the clock 18 years to the Halloween Storms of October 2003, when our planet “lost” half its satellites.

Above: Northern Lights over Houston, Texas, on Oct. 29, 2003. Credit: Christie Ponder [photo gallery]

Solar Cycle 23 was winding down. 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: An X17 flare on Oct. 28th followed by an X10 flare on Oct. 29th. Powerful CMEs struck Earth’s magnetic field only 19 hours later, sparking 3 days of severe to extreme geomagnetic storms.

An after action report from NOAA lists some of the storm’s side effects: Commercial airlines scrambled to redirect flights from the poles, where radiation levels were suddenly high. Each detour cost as much as $100,000. Many Earth-orbiting satellites experienced reboots and even unwanted thruster firings. Some operators simply gave up and turned their instruments off. Goddard’s Space Science Mission Operations Team estimates that 59% of NASA’s Earth and space science satellites were affected.

There’s a dawning awareness that something else important happened, too. Many of Earth’s satellites were misplaced.

In a 2020 paper entitled “Flying Through Uncertainty,” a team of researchers led by Thomas Berger at the University of Colorado’s Space Weather Technology, Research, and Education Center report a little-known anecdote from USAF satellite operators. During the Halloween storms, they recalled, “the majority of [low Earth orbiting] satellites were temporarily lost, requiring several days of around-the-clock work to reestablish [their positions].”

“The Halloween storms pumped an extra 3 Terrawatts of power into Earth’s upper atmosphere,” explains Martin Mlynczak, principal investigator of NASA’s SABER spacecraft, which measured the energy dump. “We didn’t feel it down on the planet’s surface, but it was a big event for Earth orbiting satellites. The extra power puffed up the atmosphere, sharply increasing aerodynamic drag.”

Above: A simulation of orbital position errors caused by a moderate geomagnetic storm for 2,653 objects in the USAF catalog. From “Flying Through Uncertainty.” [full caption]

Simulations show that even moderate geomagnetic storms can shift the position of a satellite by 10 km or more. The Halloween Storms created far larger uncertainties. This is a problem because, when you’re in a shooting gallery, you can’t dodge the bullets unless you know where they are.

“Fortunately, the Halloween storm did not cause any major collisions that we know of,” write Berger and his co-authors. “But if a geomagnetic storm on the level of the 2003 event were to occur today, the situation could be very different. Most satellite operators today have never experienced anything like the Halloween 2003 storm.”

Right now radars and telescopes in the United States Space Surveillance Network are surely working to pinpoint the debris of Kosmos 1408. Orbital solutions will allow collision warnings to be issued; satellites can dodge. However, a strong geomagnetic storm could wipe out their findings in an instant.

Intensifying geomagnetic activity is almost certain as young Solar Cycle 25 gains steam in the years ahead. It’s something to think about the next time you launch an ASAT weapon…

A Symphony of Magnetic Waves

Nov. 9, 2021: On Nov. 8th, for only a few hours, Earth’s magnetic field became very quiet. In the silence, a symphony ensued. Citizen scientist Rob Stammes recorded the performance using his magnetometer in Lofoten, Norway. “At first, the line on the digital chart recorder seemed flat,” he says, “but when I zoomed in I saw an almost musical superposition of sine waves.”

“This is very striking,” says Stammes, who has spent years observing and cataloging magnetic disturbances inside the Arctic Circle. “Note how the high-frequency Pc1 and Pc2 waves are superimposed on the slower Pc3. In musical terms, it’s a form of vibrato modulation.”

“Pc” stands for “pulsation continuous.” This is research jargon meaning, essentially, sine waves in the magnetosphere. They are present at all times, usually as a noisy cacophany of competing frequencies. Only during moments of extreme quiet can a few individual frequencies pop out and make music together.

Over the years, researchers have identified 5 types of Pc waves; Stammes recorded 3 of them. Fast Pc1 and Pc2 waves are associated with protons spiralling around Earth’s magnetic field. These waves scatter so-called “killer electrons” out of the Van Allen radiation belts, making space safer for satellites. Slower Pc3 waves are a gentle flutter caused by solar wind blowing down the flanks of the magnetosphere. (Imagine blowing across a piece of paper, making it flutter with your breath. Same idea.)

“Magnetic storms are great,” says Stammes, “but sometimes the ‘quiet’ can be just as interesting.”

Cannibal CME Sparks Low Latitude Auroras

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 the storm, auroras appeared in New Mexico and Colorado as well–far below the latitudes where they usually appear.

In Abisko, Sweden, the auroras were so bright they could be seen at sunrise:

“I almost slept through the storm,” confesses photographer Oliver Wright. “I woke up just after 5am and I could see auroras through my bedroom window. So quick coffee and headed down to the bridge over the Abisko canyon. I was watching purple auroras getting washed out by the nautical sunrise. I’ve only ever seen that once before during the Saint Patrick Day geomagnetic storm of 2015.”

more aurora images:from Marianne Bergli of Tromsø, Norway; from Marybeth Kiczenski of Bayfield, Wisconsin; from Markus Varik of Tromsø, Norway; from Chris Cook of Cape Cod, Massachusetts; from Greg Ash of Duluth Minnesota; from Genevieve of Greenwood, Maine; from Thomas Spence of Tofte, Minnnesota; from Shelley Johnson of Anacortes, Washington


Nov. 2, 2021: The CME heading for Earth is a cannibal. SOHO coronagraphs caught the storm cloud leaving the sun on Nov. 2nd following a slow-motion solar flare (M1.7) in the magnetic canopy of sunspot AR2891:

This CME is a cannibal because it ate others of its own kind. Cannibal CMEs are fast coronal mass ejections that sweep up slower CMEs in front of them. The mish-mash contains tangled magnetic fields and compressed plasmas that can do a good job sparking geomagnetic storms.

The slower CMEs, in this case, were hurled into space on Nov. 1st and 2nd by departing sunspot AR2887. The cannibal caught up with them almost immediately after leaving the sun. This NOAA computer model shows what happened:

The cannibal cloud swept up one whole CME and a portion of another. If NOAA’s model is correct, the combined CME will make first contact with our planet around 0600 UT on Nov. 4th. The model also predicts a +250 km/s increase in solar wind speed and a 6-fold jump in solar wind density in the CME’s wake. These conditions, if they materialize, would set the stage for geomagnetic storms as strong as category G2.

Subscribers to our Space Weather Alert Service will receive a text message when the CME arrives.