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An S1-class solar radiation storm is in progress on Jan. 5th. This means energetic protons from the sun are raining down on Earth. Their ionizing effect on the atmosphere is causing a polar cap absorption event (PCA). Shortwave radios inside the Arctic and Antarctic Circles won't work as well as usual until the PCA subsides.
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Sunspot AR3947 is sizzling with activity. Since Friday it has produced three X-class solar flares and multiple strong M-flares. NOAA's GOES-16 satellite recorded the extreme ultraviolet and X-ray flashes: Each flare has produced a shortwave radio blackout on Earth. Almost all longitudes of our planet have experienced intermittent loss of signal below 20 MHz during local daylight hours. Because of these flares, long-distance propagation has been unreliable.
Remarkably, no significant CMEs have emerged. These explosions have not lifted much material out of the sun's atmosphere. Future blasts may behave differently, however, and the activity shows no sign of abating as the sunspot turns toward Earth. Stay tuned! https://spaceweather.com/ "Today we have three big things on the sun: A gigantic string of big and active sunspots, a large sunspot just coming into view, and a magnificent solar prominence," reports Maximilian-Vlad Teodorescu of the Institute of Space Science in Magurele, Romania. He photographed them all on Oct. 29th: "All are far above the usual size of sunspots and prominences," says Teodorescu. "What a wonderful solar maximum!"
Three of the sunspots Teodorescu photographed pose a threat for very strong solar flares: 3869, 3872, 3874 have 'beta-gamma-delta' magnetic fields in which opposite polarities are bumping together in dangerous proximity. NOAA forecasters estimate a 75% chance of M-class solar flares and a 30% chance of X-flares during the next 24 hours. https://spaceweather.com/ For the 3rd day in a row, energetic protons are raining down on Earth. It's an S2-class radiation storm. The protons were accelerated by X-class solar flares on Oct. 24th and 26th. As a result of the storm, a shortwave radio blackout is underway inside the Arctic Circle, and cameras on spacecraft are being fogged. Indeed, most of the speckles in the SOHO coronagraph movie highlighted below are solar protons hitting the camera. This could continue for at least another 24 hours.
https://spaceweather.com/ Sunspot AR3842 exploded again on Oct. 3rd, producing the strongest solar flare of Solar Cycle 25 so far. NASA's Solar Dynamics Observatory recorded the X9.1-category blast: Radiation from the flare ionized the top of Earth's atmosphere and caused a deep shortwave blackout over Africa and the South Atlantic. Ham radio operators in the area may have noticed loss of signal at frequencies below 30 MHz for as much as a half an hour after 12:18 UTC.
The explosion also produced a halo CME. Now that a full set of images has arrived from the Solar and Heliospheric Observatory (SOHO), it's clear that the CME is potent. NOAA forecasts of a strong geomagnetic storm when it arrives on Oct. 6th are probably correct. https://spaceweather.com/ Fast-growing sunspot AR3842 erupted on Oct 1st (2220 UT), producing the second-strongest solar flare of Solar Cycle 25. The X7.1-category blast caused a shortwave radio blackout over Hawaii and hurled a CME into space. A preliminary NASA model predicts it will hit Earth on Oct. 5th. Stay tuned for the geomagnetic storm forecast.
Imagine a waterfall made of hot plasma falling from a precipice tall enough to swallow Earth five times. Here it is: Dutch photographer "Neo" captured this movie on August 28th. "For three days I've been watching these prominences around the edge of the active sun," he says. "The plasma did not stop falling for a moment."
Plasma falls have been seen on the sun many times before, yet researchers still don't fully understand them. One big mystery is how fast they fall. The sun's gravity is powerful, but not powerful enough to pull the plasma down so quickly through the thicket of solar magnetic fields. Nuclear engineers would like to figure out how this happens, because it also happens on a smaller scale in fusion reactors, frustrating their efforts to sustain an energy-producing reaction. Studies of plasma falls on the sun could lead to practical breakthroughs here on Earth. https://spaceweather.com/ Old sunspot AR3664 (now AR3697) isn't as big as it used to be, but it is still very active. Today at 1437 UT, it produced an X1.4-class solar flare: Note: The jiggling of the sun in this movie is not caused by the X-flare. Calibration offsets were underway during the flare. Credit: NASA/Solar Dynamics Observatory. A lengthy pulse of extreme ultraviolet radiation produced a deep shortwave radio blackout over the Americas. Ham radio operators may have noticed loss of signal at all frequencies below 30 MHz for 60 to 90 minutes following the onset of the flare.
This explosion was remarkable for its duration. The X-class phase alone lasted more than an hour--plenty of time to lift a CME out of the sun's atmosphere. Indeed, SOHO coronagraphs have detected a bright CME emerging from the blast site: movie. We will find out in the hours ahead whether or not the storm cloud has an Earth-directed component. Stay tuned! 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/ Giant sunspot AR3664 is no longer facing Earth. That makes it extra dangerous. Right now, the Carrington-class sunspot is passing over the sun's western limb--a region of the sun that is magnetically connected to our planet. Indeed, we are feeling the effects of that connection; take a look at this map of ongoing radio blackouts: Red zones in the map show where shortwave radio signals are being absorbed. Frequencies below 20 MHz are almost completely blacked out, a nuisance for long-distance aviators and ham radio operators.
What's causing this? Protons accelerated by solar flares in the magnetic canopy of AR3664 are following the Parker Spiral back to Earth. Think of it as a magnetic superhighway. Arriving particles are funneled by our planet's magnetic field toward the poles where they ionize the atmosphere and interfere with the transmission of shortwave radio signals. This polar cap absorption event could last for days, especially if it is boosted by more flares from AR3664. You can can monitor its progress here. 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/ The first of six CMEs hurled toward Earth by giant sunspot AR3664 hit our planet's magnetic field today. The impact on May 10th at 1645 UT jolted magnetometers around the world and sparked a severe (G4-class) geomagnetic storm. This storm is underway now. More CMEs are following close behind and their arrival could extend the storm into the weekend. Sign up for Space Weather Alerts to receive instant text messages when the CMEs arrive. The ongoing storm is producing low-latitude auroras in the southern hemisphere. Ken James sends this picture from the Snake Valley Observatory in Victoria, Australia: "The red, yellow and green colours were easily visible to my naked eye," says James. Readers in the USA should note that the southern latitude of Victoria, Australia, 37 degrees, is the same as the northern latitude of central California. That's how far down auroras could be seen if it were dark instead of daylight in North America. Why is this storm so severe? Take a look at the solar wind data from NOAA's DSCOVR spacecraft: After the CME struck, the speed of the solar wind blowing around our planet abruptly increased to more than 700 km/s. More importantly, south-pointing magnetic fields from the sun washed over the Earth, opening a crack in our planet's magnetosphere. Solar wind poured through the gap to turbo-charge the storm.
https://spaceweather.com/ Sunspot AR3615, last seen in March crackling with X-flares, is now transiting the farside of the sun. The sunspot is so big, it is affecting the way the sun vibrates, allowing researchers to detect its seismic echo. Also, NASA's rover Perseverance can see the sunspot all the way from Mars. This large active region will return to the Earthside of the sun about a week from now.
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. An artist's concept of the sun's dipolar magnetic field. Credit: NSF/AURA/NSO. 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. The last five polar field reversals observed at the Wilcox Solar Observatory (inset) "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: An artist's concept of 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/ |
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