Solar Activity That Affects Life On Earth - Blog Posts
POSSIBLE GLANCING-BLOW CME THIS WEEK: Yesterday, a magnetic filament lifted off the sun's northern hemisphere and hurled a CME into space. NOAA forecasters say it could deliver a glancing blow to Earth's magnetic field on May 23rd. If so, the impact would increase already existing odds of a G1-class geomagnetic storm.
BIG HOLE IN THE SUN'S ATMOSPHERE: Minor G1-class geomagnetic storms are possible for the next 3 days (May 19-21) as Earth passes through a wide stream of high-speed solar wind. The gaseous material is flowing from a hole in the sun's atmosphere, which stretches across most of the sun's southern hemisphere. The million-kilometer-wide structure is shown in this extreme ultraviolet image from NASA's Solar Dynamics Observatory:
This is a "coronal hole"--a region in the sun's atmosphere where magnetic fields have opened up, allowing solar wind to escape. Coronal holes look dark because hot glowing gas normally contained there is missing. In this case, it is en route to Earth.
We've seen this coronal hole before--approximately every 28 days since February. Here it is in March, and again in April. It has been spinning around with the sun, emitting a stream of material akin to a giant lawn sprinkler. The stream encounter was particularly effective in March when it sparked auroras across many northern-tier US states.
Post Apocalypse
STRONG SOLAR ACTIVITY (UPDATED): After weeks of calm, solar activity is suddenly high again. The action started on May 13th with an X1.2-class solar flare from the sun's western limb, followed on May 14th by an even stronger X2.7-flare from new sunspot 4087. Earth-orbiting satellites have detected four significant explosions so far:
Radiation from the flares has caused a series of shortwave radio blackouts around the world--first over the Americas, followed by southeast Asia, the Middle East and Africa. Ham radio operators may have noticed unusual propagation effects from stations in all directions since May 13th.
Most of this activity has come from sunspot 4087, which has an unstable 'beta-gamma-delta' magnetic field. It could explode again today. NOAA forecasters estimate a 75% chance of M-class solar flares and a 30% chance of X-flares on May 15th.
MORE STRONG FLARES: The flaring contines. In addition to the solar flares described below, active sunspot 4087 has produced two more big explosions: X2.7 and M7.7. Stay tuned for updates on these events--and get ready for more. This sunspot shows no signs of quieting down. Solar flare alerts: SMS Text
STRONG SOLAR ACTIVITY: After weeks of calm, solar activity is suddenly high again, with two strong solar flares erupting from opposite sides of the sun:
The first of these flares (X1.2) caused a brief shortwave blackout over the Americas and hurled a CME into space. A NASA model shows the CME hitting Mercury, grazing Venus, and completely missing Earth later this week.
The second flare (M5.3) caused a longer shortwave radio blackout over southeast Asia and probably hurled a CME into space. If so, it could have an Earth-directed component. Confirmation awaits fresh data from SOHO coronagraphs.
THE ELECTRIC FOREST--TREES RESPOND TO A SOLAR ECLIPSE: Solar eclipses aren't just for homo sapiens. Researchers have long known that birds, insects, and many mammals pay attention when the Moon slides in front of the sun. Now we can add trees to the list.
The study's location in the Dolomite Mountains of Italy. Photo credit: Monica Gagliano
A paper just published in the journal Royal Society Open Science reports the extraordinary reaction of an Italian mountain forest to a partial eclipse on Oct. 25, 2022. Electrical signals inside spruce trees began to pulse in unison, with older trees seeming to anticipate the eclipse before it happened.
This is unconventional research, and it may challenge what some readers think about trees. However, it is serious work conducted by experts in plant communication and published in a peer-reviewed journal of the Royal Society.
The paper reports how scientists led by Alessandro Chiolerio of the Italian Institute of Technology and Monica Gagliano of Southern Cross University attached electrodes to three Norway spruce trees and five tree stumps. Their device is like an EKG for trees. The trees were different ages, ranging from 20 to 70 years old, allowing the team to compare how age might influence bioelectrical responsiveness to the eclipse.
Electrodes connected to the spruce trees during the eclipse. Photo credit: Monica Gagliano
As the eclipse approached, electrical signals from different trees began to align; their waveforms became more similar in shape and timing. This synchronization peaked during the eclipse and gradually diminished afterward. The older trees started showing electrical changes earlier, hours before the eclipse began, while the youngest tree responded later and more weakly. The tree stumps also exhibited a bioelectrical response, albeit less pronounced than in the standing trees.
The researchers interpreted this as a coordinated "organism-like" response to a large-scale environmental event, possibly involving communication or shared signaling pathways.
The idea that trees may "talk" to one another is key to the burgeoning field of plant communication. A growing body of research (especially since the 1990s) suggests that trees form symbiotic relationships with fungi, creating vast underground networks called the "Wood Wide Web." Through these networks, trees exchange nutrients, water, and even chemical signals. They also reportedly recognize their own young and give preferential treatment to kin. Even tree stumps may retain connections to this network.
"Basically, we are watching the famous 'Wood Wide Web' in action!" says Gagliano.
Although the researchers successfully detected electrical activity in the trees, they have no idea what was being said--if anything. Perhaps it was simply a basic response to changes in temperature or light levels (about 1/3rd of the sun was covered during the eclipse). The researchers don't yet speak the "language" of arboreal electricity, so they can't decipher what they overheard. Repeating the experiment in different forests during more eclipses may be revealing.
Stay tuned for updates from the forest.
Recommended reading: Two good introductory books on plant communication and networking are "Finding the Mother Tree" by Suzanne Simard and "The Light Eaters" by Zoe Schlanger.
SOLAR WIND STORM IN PROGRESS: Earth has entered a stream of fast-moving solar wind with gusts reaching 700 km/s (1.6 million mph). G1-class geomagnetic storms and high latitude auroras are possible on May 3rd. Aurora alerts: SMS Text
A VERY BIG SUNSPOT: How big is it? Sunspot 4079 is, by far, the biggest sunspot of 2025. It stretches 140,000 km across the solar disk and covers an area equal to 50% of Carrington's sunspot in 1859. Amateur astronomer Eduardo Schaberger Poupeau of Rafaela, Argentina, peered into the sunspot's dark heart on May 2nd, and this is what he saw:
The two jet-black cores are each large anough to swallow Earth. They are bristling with hair-like solar fibrils as much as 20 thousand km long. Fibrils are, essentially, magnetic tubes that guide hot plasma in and out of the sunspot. When they start to wave back and forth, it means the sunspot is becoming unstable and about to erupt. Videos of the sunspot show dynamic activity within these structures.
Any solar flares this weekend will be geoeffective as the giant sunspot turns toward Earth.
Returning Home
GEOMAGNETIC STORMS ARE POSSIBLE TODAY: NOAA forecasters say that minor G1-class geomagnetic storms are possible today, May 2nd, as a fast-moving stream of solar wind buffets Earth's magnetic field. There is a slight chance the storm could escalate to category G2. If so, auroras would be visible after nightfall in northern-tier US states. Solar flare alerts: SMS Text
A GIANT RING OF ELLERMAN BOMBS: Astronomers are monitoring a very large sunspot now turning toward Earth. Sunspot 4079 stretches more than 140,000 km from end to end and has two dark cores each large enough to swallow Earth. Moreover, it is surrounded by a ring of Ellerman Bombs:9
Philippe Tosi took this picture from his backyard observatory in Nîmes, France, and inserted an image of Earth for scale. "It is an impressive sunspot," he says.
Note the pinpoints of light ringing the two dark cores. These are Ellerman bombs: Magnetic explosions about one-millionth as powerful as a true solar flare. A handful are circled for reference. Named after physicist Ferdinand Ellerman who studied them in the early 20th century, a single Ellerman bomb releases about 1026 ergs of energy--equal to about 100,000 World War II atomic bombs.
Ellerman bombs are a sign of magnetic complexity in a sunspot. Opposite polarities bump together, reconnect, and--boom! A full-fledged flare may not be far behind.
HIGH INTEREST" REENTRY: In 1972, the Soviet Union's Kosmos 482 spacecraft was supposed to land on Venus. Instead, it's about to return to Earth. ETA: May 10th, give or take a few days.
"The reentry of the Kosmos 482 Descent Craft will not be your standard reentry," says satellite analyst Marco Langbroek, who has been tracking the object for years. "The Descent Craft was designed to survive entry through the dense atmosphere of Venus. It will therefore likely survive reentry into the Earth’s atmosphere intact and make a crash landing. This will therefore be a high-interest reentry."

A museum replica of Venera 8, launched just days before Kosmos 482. Credit: NASA
This spacecraft was part of the Soviet Union's sucessful Venera program to explore Venus. Between 1961 and 1984, thirteen Venera probes successfully entered Venus's atmosphere, with ten landing on the planet's surface. Kosmos 482, however, never left Earth. The upper stage of its rocket shut down prematurely, leaving it in a 206 x 9802 kilometer orbit that has been decaying ever since.
"With an orbital inclination of 52 degrees, the Kosmos 482 Descent Craft could come down anywhere between 52 degrees north and 52 degrees south latitude," says Langbroek. "This includes much of south and mid-latitude Europe and Asia, as well as the Americas, Africa and Australia. (An ocean landing is most likely.)"

Above: A picture of Venus from Kosmos 482's sister craft Venera 13 [more]
It is unlikely that the parachute system will work after more than 50 years in space, so this will be a crash landing. How bad will it be? Details of the descent craft have been lost to history. Langbroek believes it is about 1 meter in diameter with a mass of ~495 kg. It won't do major damage, but you wouldn't want to be standing where it lands.
INTERPLANETARY SHOCK WAVE: An interplanetary shock wave struck Earth's magnetic field on April 24th at ~0715 UTC. What is an interplanetary shock wave? It's an abrupt change in the solar wind--probably a CME that we didn't realize was coming. This one sparked auroras in New Zealand, but no global geomagnetic storm.
STARLINK INCIDENT IS NOT WHAT WE THOUGHT: It never made sense. On Feb. 3rd, 2022, SpaceX launched a batch of 49 Starlinks to low-Earth orbit--something they had done many times before. This time was different, though. Almost immediately, dozens of the new satellites began to fall out of the sky.
At the time, SpaceX offered this explanation: "Unfortunately, the satellites deployed on Thursday (Feb. 3rd) were significantly impacted by a geomagnetic storm on Friday, (Feb. 4th)."
A more accurate statement might have read "...impacted by a very minor geomagnetic storm." The satellites flew into a storm that barely registered on NOAA scales: It was a G1, the weakest possible, unlikely to cause a mass decay of satellites. Something about "The Starlink Incident" was not adding up.
Space scientists Scott McIntosh and Robert Leamon of Lynker Space, Inc., have a new and different idea: "The Terminator did it," says McIntosh.
Not to be confused with the killer robot, McIntosh's Terminator is an event on the sun that helps explain the mysterious progression of solar cycles. Four centuries after Galileo discovered sunspots, researchers still cannot accurately predict the timing and strength of the sun's 11-year solar cycle. Even "11 years" isn't real; observed cycles vary from less than 9 years to more than 14 years long.
Above: Oppositely charged bands of magnetism march toward the sun's equator where they "terminate" one another, kickstarting the next solar cycle. [more]
McIntosh and Leamon realized that forecasters had been overlooking something. There is a moment that happens every 11 years or so when opposing magnetic fields from the sun's previous and upcoming solar cycles collide. They called this moment, which signals the death of the old cycle, "The Termination Event."
After a Termination Event, the sun roars to life–"like a hot stove where someone suddenly turns the burner on," McIntosh likes to say. Solar ultraviolet radiation abruptly jumps to a higher level, heating the upper atmosphere and dramatically increasing aerodynamic drag on satellites.
This plot supports what McIntosh and Leamon are saying:
The histogram shows the number of objects falling out of Earth orbit each year since 1975. Vertical dashed lines mark Termination Events. There's an uptick in satellite decay around the time of every Terminator, none bigger than 2022.
As SpaceX was assembling the doomed Starlinks of Group 4-7 in early 2022, they had no idea that the Terminator Event had, in fact, just happened. Unwittingly, they launched the satellites into a radically altered near-space environment. "Some of our satellite partners said it was just pea soup up there," says Leamon.
SpaceX wasn't the only company hit hard. Capella Space also struggled in 2022 to keep its constellation of Synthetic Aperture Radar (SAR) satellites in orbit.
“The atmospheric density in low Earth orbit was 2 to 3 times more than expected,” wrote Capella Space's Scott Shambaugh in a paper entitled Doing Battle With the Sun. “This increase in drag threatened to prematurely de-orbit some of our spacecraft." Indeed, many did deorbit earlier than their 3-year design lifetimes.
The Terminator did it? It makes more sense than a tiny storm.
GEOMAGNETIC STORM WATCH (G2): Moderate (G2) geomagnetic storms are possible on April 22-23 when a co-rotating interaction region (CIR) is expected to hit Earth's magnetic field. CIRs are transition zones between fast- and slow-moving streams of solar wind; they contain enhanced magnetic fields akin to those of CMEs. Sky watchers across Canada and northern-tier US states from New York to Washington should be alert for auroras. Aurora alerts: SMS Text.
A LARGE HOLE IN THE SUN'S ATMOSPHERE: A large hole in the sun's atmosphere is facing Earth and spewing a stream of fast-moving solar wind directly toward our planet. NASA's Solar Dynamics Observatory photographed the opening, which stretches almost a million kilometers across the sun's southern hemisphere:
This is a "coronal hole"--a vast region in the sun's atmosphere where magnetic fields have opened up, allowing solar wind to escape. The hole looks dark because hot gas normally contained there is missing. It's on its way to Earth.
At the top of the page, we predicted a CIR (co-rotating interaction region) would hit Earth on on April 22nd. This giant hole is the driving force behind it. Fast solar wind flowing from the hole is compressing slower-moving solar wind in front of it, creating CME-like shock waves and magnetic fields that comprise the CIR.
G2-class geomagnetic storms are likely when the CIR reaches Earth.
GEOMAGNETIC GROUND CURRENTS IN NORTH AMERICA: Space weather isn't all about the sky. It's in the ground, too. On April 16th, a severe geomagnetic storm caused electricity to flow through the rocks and soil of North America. Red zones in this animated map from NOAA show where voltages were greatest:
This 10-minute animation shows North American ground currents at the apex of the April 16th G4 geomagnetic storm
Geoelectric voltages were more than 70 times normal in the Appalachian mountain range, northern Minnesota, and northwestern Canada. Texas and other western US states were relatively unscathed.
Researchers track ground currents because in extreme cases they can cause power outages like the Great Québec Blackout of March 13, 1989. This week's storm wasn't intense or long-lasting enough to bring down power grids, but NOAA's maps show where power stations are most vulnerable.
"Generally, geoelectric amplitudes are high over metamorphic rock, such as in the Appalachians and northern Minnesota," explains Jeffrey Love of the US Geological Survey (USGS). "They are usually low over sedimentary rock such as in Texas and northwest of the Appalachians."
THE CME HAS ARRIVED: Arriving hours earlier than expected, a CME struck Earth's magnetic field on April 15th (1700 UTC), and a minor G1-class geomagnetic storm is underway as a result of the impact. It's too soon to say whether this is just the first of two expected CMEs -- or perhaps a cannibal combination. NOAA forecasters say the storm could intensify to category G3 (Strong) in the hours ahead, depending on the strength and orientation of magnetic fields in the CME's wake. CME impact alerts: SMS Text.
These data from NOAA's DSCOVR satellite show how the CME's arrival altered Earth's solar wind environment:
The density of solar wind plasma abruptly jumped by a factor of almost ten. This means the CME delivered a relatively heavy blow to Earth's magnetosphere. Stay tuned for updates as Earth's moves deeper into the CME's wake.
POTENTIALLY DANGEROUS SUNSPOT: Sunspot 4055 is seething with activity, producing at least 8 M-class solar flares during the past 24 hours alone. On April 12th, David Wilson of Inverness, Scotland, recorded hot plasma currents surging around the sunspot's magnetic canopy:
"I always check Spaceweather before I start my captures, and today it said AR4055 had flaring potential, so I followed their advice and caught this video," says Wilson. "I used my homemade solar telescope to observe the sunspot for nearly two hours."
This sunspot is potentially dangerous for two reasons: (1) It has a 'beta-gamma-delta' magnetic field that harbors energy for X-class solar flares. (2) It is moving toward the sun's western limb where it will connect itself to Earth via the magnetic Parker spiral. Any eruptions in the next few days could accelerate a hailstorm of energetic protons toward our planet.
The CENTENNIAL GLEISSBERG CYCLE: You've heard of the 11-year sunspot cycle. But what about the Centennial Gleissberg Cycle? The Gleissberg Cycle is a slow modulation of the solar cycle, which suppresses sunspot numbers every 80 to 100 years. It may have been responsible for the remarkable weakness of Solar Cycle 24 in 2012-2013. New research published in the journal Space Weather suggests that the minimum of the Gleissberg Cycle has just passed. If so, solar cycles for the next 50 years could become increasingly intense.
"CIRs are transition zones between fast- and slow-moving streams of solar wind. They contain magnetic fields and shock waves akin to those of CMEs. While CMEs require some sort of explosion on the sun, CIRs do not. They form gently from the sandwiching of solar wind streams--no solar flare required.
The arrival of the CIR on March 8th immediately caused a G1-class (Minor) storm, intensifying to category G2 (Moderate) on March 9th. Sky watchers in Iceland, Canada and multiple US states from New York to Utah saw the geomagnetic glow.
A fast-moving solar wind stream has arrived on the heels of the CIR. This is the same stream that created the CIR in the first place by compressing a region of slower solar wind ahead of it. Blowing almost 600 km/s, the fast stream could cause additional category G1 (Minor) storms on March 10th.. "