Remember that cool animation I posted earlier of AR1520 and how I said there’s no guarantee it wouldn’t unleash an X-class flare? Well at 16:48 UT today, it did. Just goes to show there’s no guarantees in space!
The X1.4-class flare will most likely affect Earth’s magnetic field as 1520 is directly facing us. Stay tuned for more!
Video & image: NASA/SDO and the AIA science team.
UPDATE: The CME associated with this flare is expected to impact Earth’s magnetosphere on Saturday between 3 and 5 p.m. EDT with “moderate to severe” activity possible. See an animated tracker here. (H/T to Francis Reddy at GSFC.) Also in the lineup for impact are MESSENGER and MSL.
Artist's impression of cosmic rays striking Earth (Simon Swordy/University of Chicago, NASA)
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When a moderate-sized M-class flare erupted from the Sun on May 17, it sent out a barrage of high-energy solar particles that belied its initial intensity. These particles traveled at nearly the speed of light, crossing the 93 million miles between the Sun and Earth in a mere 20 minutes and impacting our atmosphere, causing cascades of neutrons to reach the ground — a rare event known as a ground level enhancement, or GLE.
The first such event since 2006, the GLE was recorded by a joint Russian/Italian spacecraft called PAMELA and is an indicator that the peak of solar maximum is on the way.
The PAMELA spacecraft — which stands for Payload for Antimatter-Matter Exploration and Light-nuclei Astrophysics — is designed to detect high-energy cosmic rays streaming in from intergalactic space. But on May 17, scientists from NASA’s Goddard Space Flight Center convinced the Russian team in charge of PAMELA to grab data from the solar event occurring much closer to home.
This graph shows the neutrons detected by a neutron detector at the University of Oulu in Finland from May 16 through May 18, 2012. (University of Oulu/NASA's Integrated Space Weather Analysis System)
The result: the first observations from space of the solar particles that trigger the neutron storms that make up a GLE. Scientists hope to use the data to learn more about how GLEs are created, and why the May 17 “moderate” solar flare ended up making one.
“Usually we would expect this kind of ground level enhancement from a giant coronal mass ejection or a big X-class flare,” said Georgia de Nolfo, a space scientist at NASA’s Goddard Space Flight Center. “So not only are we really excited that we were able to observe these particularly high energy particles from space, but we also have a scientific puzzle to solve.”
Fewer than 100 GLEs have been recorded in the last 70 years, with the most powerful having occurred on February 23, 1956. Like most energetic solar outbursts, GLEs can have disruptive effects on sensitive electronics in orbit as well as on the ground, and based on recent studies may even have adverse effects on cellular systems and development.
The M-class flare from AR 1476 on May 17, 2012 (at right) Courtesy NASA/SDO and the AIA science team.
Sunspots from today and from 65 years ago, with planet sizes for comparison.
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The short answer? Really big. The long answer? Really, really big.
The image above shows sunspot regions in comparison with the sizes of Earth and Jupiter, demonstrating the sheer enormity of these solar features.
Sunspots are regions where the Sun’s internal magnetic fields rise up through its surface layers, preventing convection from taking place and creating cooler, optically darker areas. They often occur in pairs or clusters, with individual spots corresponding to the opposite polar ends of magnetic lines.
(Read “What Are Sunspots?”)
The image on the left was acquired by NASA’s Solar Dynamics Observatory on May 11, 2012, showing Active Region 11476. The one on the right comes courtesy of the Carnegie Institution of Washington, and shows the largest sunspot ever captured on film, AR 14886. It was nearly the diameter of Jupiter — 88,846 miles (142,984 km)!
“The largest sunspots tend to occur after solar maximum and the larger sunspots tend to last longer as well,” writes SDO project scientist Dean Pesnell on the SDO is GO blog. “As we move through solar maximum in the northern hemisphere and look to the south to pick up the slack there should be plenty of sunspots to watch rotate by SDO.”
Sunspots are associated with solar flares and CMEs, which can send solar storms our way and negatively affect satellite operation and impact communications and sensitive electronics here on Earth. As we approach the peak of the current solar maximum cycle, it’s important to keep an eye — or a Solar Dynamics Observatory! — on the increasing activity of our home star.
(Image credit: NASA/SDO and the Carnegie Institution)
Solar flares pose a major hazard to electronics and infrastructure in Low Earth Orbit, but they may have played a role in kick-starting life on Earth. Credit: NASA/SDO/J. Major
This big! The M1.7-class flare that erupted from active region 1461 on Monday, April 16 let loose an enormous coronal mass ejection many, many times the size of Earth, making this particular writer very happy that our planet was safely tucked out of aim at the time… and 93 million miles away.
The image above was obtained by NASA’s Solar Dynamics Observatory’s AIA 304 imaging instrument on Monday during the height of the event. I rotated the disk of the Sun 90 degrees to get a landscape look over the eastern limb, cropped it down and then added an Earth image to scale — just to show how fantastically huge our home star really is.
A cluster of coronal cells seen by SDO on June 17, 2011. (NASA/SDO AIA instrument)
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There’s something new under the Sun… well, just above the Sun, actually. Scientists at the Naval Research Laboratory have spotted structures in the Sun’s super-hot corona that may shed some light on the way its magnetic fields evolve — especially near the edges of vast, wind-spewing coronal holes.
Coronal holes are regions where the Sun’s magnetic field doesn’t loop back down but rather streams outward into space. Appearing dark in images captured in ultraviolet wavelengths, these holes in the corona allow solar material to flow directly out into the solar system, in many cases doubling the normal rate of the solar wind.
Recently witnessed by NRL researchers using NASA’s SDO and STEREO solar-observing spacecraft, features called coronal cells exist at the boundaries of coronal holes and may be closely associated with their formation and behavior.
The coronal cells are plumes of magnetic activity that stream upward from the Sun, occurring in clusters. Likened to “candles on a birthday cake”, the incredibly hot (1 million K) plumes extend outwards, punching though the lower corona.
Seen near the center of the Sun’s disk, the cells appear structurally similar to granules — short-lived areas of rising and falling solar material on the Sun’s photosphere — but seen from an angle via STEREO, the cells were witnessed to be much larger, elongated and extending higher into the Sun’s atmosphere. For comparison, granules are typically about 1,000 km in diameter while the coronal cells have been measured at 30,000 km across.
“We think the coronal cells look like flames shooting up, like candles on a birthday cake,” said Neil Sheeley, a solar scientist at the Naval Research Laboratory in Washington, D.C. “When you see them from the side, they look like flames. When you look at them straight down they look like cells. And we had a great way of checking this out, because we could look at them from the top and from the side at the same time using observations from SDO, STEREO-A, and STEREO-B.”
Watch a video below of cells made from images acquired by STEREO-B… note how their elongated structure becomes evident as the cells rotate closer to the Sun’s limb.
NRL researchers also noted that the coronal cells appeared when adjacent coronal holes closed and disappeared when the holes opened, suggesting that the holes and cells share the same magnetic structure. In addition, the coronal cells were seen to disappear when a solar filament would erupt nearby, being “extinguished” as the cooler strand of solar material moved across them. Once the filament passed, the cells reformed — again, indicating a direct magnetic association.
The coronal cells were also identified in earlier images from ESA and NASA’s SOHO and Japan’s Hinode spacecraft.
It’s hoped that further study of these candle-like structures will lead to more knowledge of our star’s complex magnetic field and the effects it has on space weather and geomagnetic activity experienced here on Earth.
Read the press release from the Naval Research Laboratory here, and on NASA’s STEREO site here.
NASA’s Solar Dynamics Observatory captured this video on March 27 – 28 of two large areas of “dark” plasma on the Sun’s limb, twisting and spiraling in our star’s complex magnetic field. The southern region bears an uncanny resemblance to three figures swaying to some spooky, unheard music… a real “danse macabre” on the Sun!
SDO AIA 211 image showing a large triangular hole in the Sun's corona on March 13
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An enormous triangular hole in the Sun’s corona was captured earlier today by NASA’s Solar Dynamics Observatory, seen above from the AIA 211 imaging assembly. This gap in the Sun’s atmosphere is allowing more charged solar particles to stream out into the Solar System… and toward Earth as well.
Normally, loops of magnetic energy keep much of the Sun’s outward flow of gas contained. Coronal holes are regions — sometimes very large regions, such as the one witnessed today — where the magnetic fields don’t loop back onto the Sun but instead stream outwards, creating channels for solar material to escape.
The material constantly flowing outward is called the solar wind, which typically “blows” at around 250 miles (400 km) per second. When a coronal hole is present, though, the wind speed can double to nearly 500 miles (800 km) per second.
Increased geomagnetic activity and even geomagnetic storms may occur once the gustier solar wind reaches Earth, possibly within two to three days.
The holes appear dark in SDO images because they are cooler than the rest of the corona, which is extremely hot — around 1,000,000 C (1,800,000 F)!
Here’s another image, this one in another AIA channel (193):
Even though the CME unleashed by active region 1429 initially hit Earth a bit softer than expected yesterday (read why here), it ended up gaining some extra “oomph” once the magnetic fields lined up right… enough to ignite some amazing displays of aurorae like the one shown above over Iceland, photographed by Jónína Óskarsdóttir!
And that wasn’t the last we’d hear from AR1429 either; at around 10:30 pm EST on March 8, the region lit up again with an M6.3 flare… although smaller than the previous X5.4-class flare, it produced a temporary radio blackout and released another Earth-directed CME, which is expected to arrive in the coming hours.
Dr. Alex Young, solar physicist at NASA’s Goddard Space Flight Center, reported this morning on his blog The Sun Today:
The flare produced a temporary radio blackout as well as a possible Earth directed CME. We will have to wait and see. The sunspot group still shows potential for more activity as the region sits near the central meridian of the Sun. Facing directly at Earth this is a prime location to produce more geo-effective solar activity.
Here is a look at the flare captured by the 131 Angstrom wavelength camera on the Solar Dynamics Observatory (SDO). This shows us the super hot 5-10 million degree plasma produced by the solar flare.
M6.3-class flare from AR1429. (NASA/SDO/AIA team)
Dr. Young also noted that bright aurorae could be visible in lower latitudes as a result of the latest CME, expected to impact Earth at 1:50 am EST:
Aurora watchers at higher latitudes such as the northern US should keep their eyes out in the early morning and maybe even into tonight depending upon how this storm progresses.
Many times the size of Earth, active region 1429 has been the source of at least five significant flares over the past week. As it moves across the face of the Sun, its shape has become more and more complex — a sure sign, notes Dr. Young, that magnetic forces within it are twisting further and further towards a breaking point. And when they snap, there’s a flare.
“It’s interesting, they kind of look like a mole,” Dr. Young said during an interview on March 8. “And when you monitor a mole, they tell you as long as it stays in a nice symmetric shape and it doesn’t become really complicated and complex, it’s okay. It’s the same sort of thing with sunspots… when they become complicated and twisted, then that mean the magnetic fields inside of them have become more twisted, like a rubber band twisting around until little knots pop up in it. And right now we have been monitoring that sunspot and it is getting more complex.”
As far as the effects we see here on Earth are concerned, that’s all about the resulting CME — the enormous cloud of charged solar particles that gets blown out into the Solar System. If that cloud impacts Earth’s magnetic field, and if the direction of the cloud happens to be opposite the direction that Earth’s magnetic field is pointed, a lot of energy is “pumped into” our magnetosphere, resulting in a geomagnetic storm.
AR1429 (NASA/SDO/HMI Intensitygram)
During yesterday’s CME impact the Earth’s magnetic field was pointed north — the same direction as the CME. As a result much of the solar material simply flowed along and over it. But the wake ended up getting caught up in the south-directed part of the field, ramping up the energy index (measured as Kp) as the hours progressed. As yet there’s no way to know for certain how a particular CME will align with Earth’s magnetic field.
According to physicist Dr. Philip Scherrer of Stanford University, “we still need better — or perhaps faster — models” to be able to accurately predict the orientation of incoming CMEs. “We are perhaps a few years of research away from completing the picture.”
Currently the geomagnetic storm level is at G3, which according to the NOAA’s Space Weather Scale could result in voltage problems on power systems, increased drag on satellites and “intermittent satellite navigation and low-frequency radio navigation problems… and aurora has been seen as low as Illinois and Oregon.”
So keep an eye out for northern lights in tonight’s skies, and stay tuned for more updates!
Thanks to Dr. Alex Young for the information! You can follow him on Facebook and Twitter and on his personal blog The Sun Today. Also thanks to Dr. Phil Scherrer at Stanford University and SpaceWeather.com for the heads-up on Jónína’s photo. See more of her aurora photography here. (Used with permission.)
Active Region 1429 unleashed an X5.4-class solar flare early this morning at 00:28 UT, as seen in this image by NASA’s Solar Dynamics Observatory (AIA 304). The eruption belched out a large coronal mass ejection (CME) into space but it’s not yet known exactly how it will impact Earth — it may just be a glancing blow.
Solar flares are categorized by a scale according to their x-ray brightness. X is the strongest class, followed by M and then C-class. Within each class the numbers 1 through 9 subdivide the flares’ intensity.
A run-in with an X5-class flare is a major geomagnetic event that can cause radio blackouts on Earth and disrupt satellite operations, as well as intensify auroral activity.
The GOES satellite data for the March 7 flare is below:
The CME is expected to impact Earth sometime on the 8th or 9th. Check back here or at Spaceweather.com for updates on the storm (and any subsequent aurora photos!)
Also, check out the video below, assembled by the SDO team. Just after the X5.4-class flare another smaller X1-class flare occurred, sending a visible wave cross the Sun.
Image courtesy NASA, SDO and the AIA science team. And thanks to Camilla Corona SDO for all the updates!
SDO AIA image of the Sun and Moon at 14:11 UT on Feb. 21, 2012
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The Sun seems to be glowing in traditional Mardi Gras colors in this image, made from three AIA channels taken today at approximately 14:11 UT (about 9:11 a.m. EST) as the Moon passed between it and the Solar Dynamics Observatory spacecraft. Looks like it’s that time of year again!
During portions of the year, the Moon transits the Sun on a regular basis from the perspective of NASA’s SDO spacecraft, which lies within the Moon’s orbit. When this happens we are treated to an improvised eclipse… and it gives SDO engineers a way to fine-tune the observatory’s calibration as well.
Here are more AIA views of the same event captured in different wavelengths:
Lunar transit on 2-21-12; AIA 304Lunar transit on 2-21-12; AIA 193Lunar transit on 2-21-12; AIA 4500
…and here’s an interesting image taken in HMI Dopplergram:
HMI Dopplergram image of transit
While the AIA (Atmospheric Imaging Assembly) images the Sun in light sensitive to different layers of its atmosphere, the Helioseismic and Magnetic Imager (HMI) studies oscillations in the Sun’s magnetic field at the surface layer.
And if you happen to be reading this as of the time of this writing (appx. 10:06 a.m. EST) you can keep up with the latest images coming in on the SDO site at http://sdo.gsfc.nasa.gov/.
It’s Mardi Gras and the Moon doesn’t want to miss out on any of the fun!
Images courtesy of NASA/SDO and the AIA, EVE, and HMI science teams. Hat-tip to Mr. Stu Atkinson who called the AIA alert on Twitter.
