King-size sunspot slip-slides away

Active Region 2192 will soon pass beyond the western limb to the farside of the Sun. While it’s size has decreased slightly, it still harbors a complex magnetic field and potential for “farewell flare” or two. This photo was taken today October 28th. Credit: NASA/SDO

Big, attention-getting and explosive, sunspot region 2192 will make a final bow before departing for the farside of the Sun in the next couple days. Many of us grabbed a souvenir photo of the giant spot during last week’s partial solar eclipse. Given its size and complexity there’s an excellent chance it will return in mid-November when the Sun carries it around for Act II.

The most recent large flare from Region 2192 was a powerful X2-class on October 27th. This photo shows the view in ultraviolet light from NASA’s Solar Dynamics Observatory. Credit: NASA

Despite shooting off 5 X-class and 12 M-class flares, none of them lofted a coronal mass ejection (CME) toward the Earth, the reason why there have been no significant auroras during its transit. CMEs are enormous clouds of subatomic particles – mostly protons and electrons – that can strongly interact with Earth’s magnetic field to do everything from damaging satellite electronics and poorly protected power grids to producing spectacular displays of northern lights.

Explosive, particle-releasing flares from region 2192 as it rounds the Sun’s western limb can spiral back directly to Earth along the Sun’s magnetic field lines like a curve ball. Credit: Nathan Schwadron, UNH-EOS

But don’t say ‘bye-bye’ to 2192 just yet. According to Dr. Tony Phillips at Spaceweather, the western limb of the Sun is well-connected to Earth. Should the giant spot flare in the next couple days, particles could spiral back along the Sun’s magnetic field lines directly our way. There’s hope yet for auroras.

Biggest sunspot in 5 years may steal the show during today’s eclipse

Active region 2192 (AR 2192) is about the same size as the planet Jupiter or 87,000 miles end to end. This illustration is based on a photo of the  sunspot group taken October 22. Click for more information and animations. Credit: NASA/SDO/Alex Young

Wow, have you ever? Look at that sunspot group. If it seems bigger than any you’ve ever seen you’re right. At least in the last five years. Active region 2192 is the largest sunspot group recorded so far in Solar Cycle 24 which began in 2009. Solar cycles typically last about 11 years and chart the rise and decline of sunspots, flares and other solar activity.

The giant spot group 2192 faces Earth squarely today and should look spectacular during this afternoon’s partial solar eclipse.  Here we see many cooler, darker umbrae surrounded by the lighter penumbrae. The group has a magnetically complex beta-gamma-delta magnetic field ripe for flaring. Credit: NASA/SDO

Yesterday I grabbed my #14 welder’s glass and couldn’t believe how easy it was to see this behemoth. If you have a filter ready for today’s partial solar eclipse, use it to look at the sun anytime, and you’ll see what I mean.

Rarely do naked eye sunspots look like more than dark dots. Region 2192 stands apart. Look carefully through your filter and you’ll discern that the left side (eastern half) looks darker than the western side. That’s because most of the darker bits, called umbrae, are concentrated there.

The sun this morning Oct. 23 with our featured sunspot group facing toward Earth. Credit: NASA/SDO

Sunspots have two parts – a dark core (or cores) called an umbra surrounded by a pale, skirt-like penumbra. Each spot group marks a region on the sun’s fiery outer skin where magnetic energy is concentrated. The magnetic forces that permeate the Sun are the same as those that flow the magnets on your refrigerator but contain vastly more energy because they cover huge regions of the Sun’s surface or photosphere.

Strong magnetic fields within a sunspot group quell the turbulent churning of the photosphere, chilling the region by several thousand degrees. Sunspots appear dark against the Sun’s blazing disk because they’re cooler. If you could rip them away from the Sun and see them alone against the sky, they’d be glaringly bright.

The crazy big sunspot group unleashed an X-class flare around 9 a.m. October 22 seen in these photos taken in two “flavors” or far ultraviolet light by NASA’s Solar Dynamics Observatory. Credit: NASA/SDO

Twisty fields of magnetic energy looping above sunspots can become unstable in the hot, turbulent environment of the Sun’s surface, which bubbles and boils like overcooked oatmeal in a microwave oven, and release their pent-up power in violent explosions called solar flares.

2192 has been no stranger to flares. Harboring a complex beta-gamma-delta magnetic field where the magnetic “north poles” and “south poles” lie side by side, they practically beg to explosively reconnect. Since Monday, the spotted beast has spewed two X-class (most powerful) and 8 M-class (medium strength) flares. So far though, none has been directed toward the Earth.

Watch the big group rotate onto the sun’s face and grow in the 72-hour animation made with NASA’s Solar Dynamics Observatory

That’s likely to change very soon since the group is now squarely facing the planet. Already, NOAA’s space weather forecast calls for a 95% chance for more M-class and 55% chance for X-class flare in the next 24 hours. Space weather is expected to be strong during the same period. That might mean auroras coming around as soon as this evening. I’ll keep you posted.

Not only will the sun be eclipsed this afternoon but the planet Venus shines just 1.1 degrees to its north. Venus is very close to superior conjunction which occurs early Saturday. In the photo, the planet is in the background well behind the Sun. Don’t count on seeing Venus – too much glare! This photo was taken from space by NASA’s Solar and Heliospheric Observatory this afternoon using a coronagraph to block the Sun from view. Credit: NASA/ESA

Good luck with today’s eclipse. If you need more information including viewing times for your city, please see my earlier blog on the topic.

Monster sunspot could stir up auroras

The sun photographed this morning by NASA’s Solar Dynamics Telescope at 11:30 a.m. CDT this morning October 18. Credit: NASA

Not today and not tomorrow, but a monster sunspot group rounding the eastern limb of the sun could spunk up the fall aurora season. Active region 2192 harbors a Jupiter-sized sunspot that’s just now visible with the naked eye using a safe solar mylar filter or #14 welder’s glass. I spotted it very close to the southeastern edge of the sun today. In the coming days, it will rotate into better view, making for an easy catch with the naked eye or small telescope. I can’t emphasize enough the importance of a safe filter. You can purchase one HERE for naked eye viewing or HERE for your telescope.

Coronal mass ejection shot out by flare activity in new sunspot group 2192 on October 14 before it even rounded the sun’s limb. Image from the SOHO coronagraph. Click for video. Credit: NASA/ESA

Even before the behemoth came into view, it spawned a brilliant coronal mass ejection on October 14 and several M-class medium strength flares. If we assume that the giant spot stays potent, the sun will rotate it around to face Earth in about 6 days. Flaring and other activity would then stream in our direction.

It will also spice up the partial solar eclipse next Thursday afternoon. Watch for the black limb of the moon to not only eclipse the sun but this sunspot too!

Update: Sunspot group 2192 unleashed an strong X-1 class flare around midnight Oct. 18-19. Any material it may have launched into space would have missed Earth by a wide margin because of the group’s position near the sun’s edge.

Nearby red dwarf star unleashes X100,000 superflare

The largest flare ever recorded on the sun, an X 45 event in November 2003, pales in comparison to the estimated X 100,000 flare seen on the red dwarf star DG CVn on April 23 by NASA’s Swift satellite. The sun image is an actual photo; the dwarf star flare an artist’s view. Credit: NASA

Sometimes big things come in small packages. Last April, DG CVn, a red dwarf star only one-third the size of the sun, cut loose with a flare 10,000 times more powerful than any solar flare ever recorded. The sun’s grandest was an X 45 on November 4, 2003 which happily was directed off its western limb away from Earth. Had it happened closer to the center of the solar disk, damage to satellite electronics and power grids on the ground might have been substantial.

NASA’s Swift mission detected a record-setting series of X-ray flares unleashed by DG CVn, a nearby binary consisting of two red dwarf stars, illustrated here. At its peak, the initial flare was brighter in X-rays than the combined light from both stars at all wavelengths under normal conditions. Credit: NASA’s Goddard Space Flight Center/S. Wiessinger

The superflare erupted from one or the other of two closely-orbiting red dwarfs in the constellation of Canes Venatici (abbreviated CVn) located beneath the handle of the Big Dipper. While only 60 light years from Earth, the two stars orbit each other only three times Earth’s distance from the sun which is too close for the Swift satellite to know which one did the deed.

At its peak the flare shot up to 360 million degrees F (200 million C) or 12 times hotter than the center of the sun. Despite its magnitude, the star is too far away to pose any harm to Earth. As to how a smaller, cooler dwarf could unleash such an energetic blast, we have two important leads.

The sun still has a lot pep left. This M7.3 (medium class) flare erupted along the sun’s western edge on October 2 as seen by the Solar Dynamics Observatory. It was not Earth-directed. Credit: NASA

Astronomers estimate DG CVn was born about 30 million years ago, which makes it less than 0.7% the age of the solar system. Like children, youthful stars are blessed with energy and show it through rapid rotation – DG completes one spin in just under a day or 30 times faster than the sun. The sun also rotated faster in its youth and may well have produced a few of its own superflares. Now it spins once every 27 days, fast enough to amplify magnetic fields to X-class strength but no match for the younger set.

Magnetic energy gets concentrated around sunspots or starspots in the case of DG CVn. In the turbulent environment, opposite polarities (north and south poles) can snap together and reconnect, releasing gobs of stored energy as a flare.

Flares are classified according to their energy output. The weakest – A,B and C-class – have almost no effect on Earth. M-class or medium flares accompanied by blasts of solar particles can cause radio blackouts and fire up northern and southern lights. The strongest are the X-class, which can lead to long-lasting radiation storms and nights-long auroral displays.

Aftermath of the X 45 flare in November 2003 clearly shows loops of solar gases outlining the powerful magnetic field rising above the sunspot group (not visible) below. Credit: NASA

At 5:07 p.m. EDT on April 23, the rising tide of X-rays from DG CVn’s superflare triggered Swift’s Burst Alert Telescope (BAT).

“For about three minutes after the BAT trigger, the superflare’s X-ray brightness was greater than the combined luminosity of both stars at all wavelengths under normal conditions,” noted Goddard’s Adam Kowalski, who is leading a detailed study on the event. “Flares this large from red dwarfs are exceedingly rare.”

Three hours later the system exploded with another weaker flare. More flares continued in a series for the next 11 days like aftershocks from an earthquake. Astronomers have observed the same phenomenon with the sun called “sympathetic flaring” where one explosion triggers another.

Stars delight the eye and make the Earth an abode for life, but don’t get too close. They’re scary.


Twin solar storms may stoke auroras tonight Sept. 11-12

A CME or coronal mass ejection from the sun on September 9 is expected to pass Earth later today and possibly spark auroras tonight. Credit: NASA/ESA

(Click HERE for updates))

Two bursts of solar particles propelled by flares on September 9th and 10th are expected to arrive starting tonight and possibly touch off a moderate G2 geomagnetic storm. Translation: auroras may bloom in the next few nights!

A moderate M4 flare occurred early on September 9th followed by a more powerful X1.6 yesterday afternoon. Provided the magnetic field the particles come packaged in points in the right direction – south – these bursts have good potential for creating auroras tonight and again over the weekend.

A second, Earth-directed CME leaves the sun in the wake of the X1.6 flare on September 10th. Credit: NASA/ESA

The timing is good because the moon is past full and won’t be too bright. During a moderate storm, auroras are often seen across the northern tier of states and Canada. According to the latest NOAA space weather forecast, activity should kick up but remain shy of storm level from 9 p.m.-midnight Central Daylight Time tonight September 11th.

The brunt of the storm is expected from 1-4 a.m. tomorrow morning the 12th with effects lasting until 7 a.m.

This may only be the start of an even stronger storm anticipated Friday night and continuing into the weekend beginning from yesterday’s flare. That one blasted material directly toward Earth. Always a good omen for auroras.

Earth’s magnetic bubble, generated by motions within its iron-nickel core and shaped by the solar wind, is called the magnetosphere. It extends some 40,000 miles forward of the planet and more than 3.9 million miles in the tailward direction. Credit: NASA

As always with northern lights, keep in mind they’re fickle. Most of the time, Earth’s magnetic defense – a humongous, teardrop-shaped bubble of magnetism called the magnetosphere –  acts as a bulwark against strong solar winds, letting them slide by harmlessly. We’ll see what happens on this round, but I’m optimistic.

The Earth weather forecast for my locale is mostly clear tonight, so I’ll be monitoring the sky. Stop back later for an update.

* UPDATE 9 p.m. CDT: Quiet so far. Auroras still holed up in Hudson Bay and Quebec. The magnetic field direction of the arriving wind from the sun shows a lot of variation (see ACE satellite plot, topmost graph showing Bz) rising and falling from positive to negative. Negative is good! A prolonged stay at -10 or lower increase the chance of seeing the aurora.

Shhh! Don’t wake the sun

Contrast these views of the nearly spotless sun on July 16-17, 2014 with a picture taken about two weeks earlier (below). Credit: Giorgio Rizzarelli

Who doesn’t enjoy a nap on a lazy summer afternoon? That’s what the sun’s been up to past few days. Instead of a steady parade of sunspots, it put its pencils away and went to sleep. For a time on July 17 not a singe magnetic blemish marred the entire Earth-facing hemisphere. The last time that happened was nearly 3 years ago on Aug. 14, 2011.

Ten groups including three visible with the naked eye dot the sun on July 8, 2014. Credit: NASA

The solar blank stare lasted but a day; by the 18th two small groups emerged. Today three little spot clusters have emerged but again, they’re on the small side.

I think the reason the sun looks so stark is that only two weeks ago nearly a dozen sunspot regions freckled the disk including three visible with the naked eye with a safe solar filter.

These ups and downs aren’t unusual unless this downturn continues for weeks. Expect more bubbles of magnetic energy to rise from beneath the glaring surface of the sun called the photosphere and spawn fresh groups soon. Because we now have eyes on the farside of the sun courtesy of the dual STEREO solar probes, we know the complete story. There are at least seven spotted regions in hiding there today.

Sunspot numbers are plotted for the last three solar cycles through the present. The double peak of the current cycle is shown. Credit: NASA

Sunspots and flares peak approximately every 11 years. We’re still riding the roller coaster near the top of the arc after the most recent solar maximum in late 2013. Some maxima are strong, others weak. The current max – Cycle 24 – is the weakest since Cycle 14 in February of 1906 and one of the wimpiest on record. Occasionally a cycle will have two peaks like the current one. The first peak occurred in Feb. 2012 and the second just this past June. What makes Cycle 24 even more unusual is that the second peak is higher than the first – the first time this has ever been recorded. Like people, every maximum has a personality of its own.

Doug Bieseker of the NOAA Space Weather Prediction Center has analyzed historical records of solar activity and he finds that most large events such as strong flares and significant geomagnetic storms typically occur in the declining phase of solar cycles—even weak ones, so don’t give up hope for some great auroral displays ahead.

A coronal mass ejection blew off on the farside of the sun early this morning July 20. It appears to envelop Jupiter, but the planet is 490 million miles in the background. SOHO uses an occulting disk to block the brilliant sun. Credit: NASA/ESA

The sun’s got a buddy this week – Jupiter! We can’t see the planet from the ground because it’s swamped by solar glare, but the Solar and Heliospheric Observatory (SOHO) has a great view from space. Watch the sun approach from the right and pass the planet over the next few days. After the 24th, Jupiter will move into the morning sky.

Huge sunspots scar the sun this week

Ten groups including three visible with the naked eye protected with a safe filter dot the sun today. Photo by the Solar Dynamics Observatory (SDO) taken at 8 a.m. CDT today July 9. Credit: NASA

A trio of impressive sunspot groups are parading across the sun’s face this week. Regions 2108, 2109 and 2110 are all closely-spaced and near the center of the disk today. All three require nothing more than a pair of eyes and a safe solar filter to view.

The sun seen through a standard 200mm telephoto lens and solar filter this morning gives you an idea of how the big sunspot groups look to the naked eye. Credit: Bob King

I took a look through my handy #14 welders glass this morning and saw 2110 distinctly; the other two groups blended into a single ‘spot’ at first. Looking closely I could barely split them into two separate dots. The view was spectacular at 30x in my little telescope with a total of ten sunspot groups and lots of fine detail in the three biggest.

Given high sunspot counts, the chance for flaring has been increasing in recent days. Today there’s a 75% chance for moderately strong M-class flares and 20% chance for the most powerful X-class variety.

Safe solar filters come in several varieties of optical / coated plastic and glass. Click to see ones you can purchase from Rainbow Symphony. Credit: Bob King

Curiously, none of the three biggies has shot off a large flare in the past day or two; they’re all currently stable. But the inconspicuous group 2113 fired off a beefy M6 flare only yesterday. It’s not expected to affect Earth, but because 2113 hides a complex magnetic field, future M-class or stronger blasts may be possible.

M6-class solar flare eruption from sunspot group 2113 captured July 8, 2014 at 11:24 a.m. by SDO. Credit: NASA

It seems like we’re due for aurora, so I’d be surprised if the current activity doesn’t lead to at least a minor storm soon. I’ll keep you updated.

Boom! Boom! Boom! A solar flare triple crown

Three X-class flares erupted in sunspot group 2087 over a 24-hour period on June 10-11, 2014. A portion of the coronal mass ejections from the eruptions may brush the Earth in the next few days. Credit: NASA

Move over California Chrome.  After delivering three X-class flares in two days, sunspot group 2087 wins the triple crown for solar eruptions. And the fun’s not over yet.

The large, complex sunspot region 2087, pictured today June 12 at 8:30 a.m CDT, kicked off three powerful X-class flares on June 10 and 11. More flares are expected from the group in the coming days as it turns toward the Earth. Credit: NASA

Between it and two other spotted regions (2080, 2085) there’s a 60% chance for moderate M-class flares and 30% chance for more X-flares through Saturday. Plus, it turns out that part of the blast from 2087′s double-X flare is whooshing its way toward Earth right now.

Look at all the sunspots! Skywatchers with safe solar filters have a bounty of observing opportunities this week. Catch the big groups 2080 and 2085 (far right) before they rotate over to the sun’s other side. Credit: NASA

Most of the solar plasma blasted sideways off the sun after the eruptions but not all. NOAA space weather forecasters now predict a 20-25% chance of minor auroral storming overnight tonight through Saturday. With each day that passes, region 2087 inches closes to the center of the sun, where it will face Earth more directly, improving the outlook for auroras in the wake of new flares.

New sunspot group enters the stage with guns a-blazing

If ever an “X marked the spot”, this ‘x’ is it. It’s the first of a pair of x-ray flares that popped this morning at 6:42 a.m. CDT in sunspot region 2087. Photo taken in extreme ultraviolet light by NASA’s Solar Dynamics Observatory. Credit: NASA

Sunspot region 2087 announced its arrival on the sun’s southeastern limb today with a real show of firepower. Like a double-barreled shotgun, the group blasted off an X2.2 flare at 6:42 a.m. CDT followed 70 minutes later by an X1.5 at 7:52.

The second flare, an X1.5, peaked around 7:57 a.m. CDT today June 10. Credit: NASA

Although neither was directly in line with Earth, ultraviolet light from the explosions caused a wave of ionization in our planet’s upper atmosphere that affected radio propagation over Europe. Images from NASA’s STEREO solar spacecraft show a coronal mass ejection moving off to one side of the side. It’s not expected to affect the Earth.

The lively sunspot group 2087 has just rotated around the southeastern limb of the sun. 2080 and 2085 are both magnetically complex groups that could spawn M-class flares of their own. Photo taken this afternoon at 1:15 p.m. CDT. Credit: NASA / SDO

Interestingly, the ACE spacecraft, which measures changes in the direction of the magnetic field bundled with the solar wind, dipped south right around the time of the flares. While the two events may be unrelated, anytime the field tilts south, conditions are opportune for the sun’s particle wind to hook into Earth’s magnetic field and possibly fire up auroras.

A large coronal mass ejection, sparked by the double-flare photographed at 9:39 a.m. today by NASA’s STEREO-B spacecraft, expands away from the sun. Credit: NASA

Though it may not be related, the magnetic direction of the wind has been rapidly shifting from north and south all morning and afternoon. Solar astronomers had expected to see flares from sunspot regions 2080 and 2085. Both have complicated delta class magnetic fields ripe with the potential for sparking solar storms. Both also squarely face the Earth. Should an X-class flare erupt in either, the material ejected could wind up producing a geomagnetic storm and accompanying northern lights later this week. So far, they’ve been ‘quiet’ today.

There’s also a chance the plasma cloud released by the X-flare blasts could strike a glancing blow to Earth’s magnetic field; the new group may also continue to produce flares as it rotates into a favorable, Earth-facing position on the sun’s disk.

March monster flare gives NASA an eyeful

A up-close view of the March 29 X-1 flare taken by NASA’s IRIS spacecraft. Flares are colossal explosions that occur when strong magnetic fields – often over complex sunspot groups –  get twisted and then reconnect, releasing vast amounts of stored energy. Credit: NASA

On March 29 this year, sunspot group 2017 unleashed a powerful X1-class flare seen by more telescopes on Earth and in space than any other flare in history.

Four different NASA spacecraft and one ground-based observatory captured photos and data of the solar storm in multiple wavelengths of light. Fortuitously, three of them had been aimed on the group a day in advance in anticipation of a possible eruption.

Views of the flare in three different wavelengths of ultraviolet light made by NASA’s Solar Dynamics Observatory (SDO). The big spikes at left show that the flare was so intense it saturated the instrument’s detector. Credit: NASA

“This is the most comprehensive data set ever collected by NASA’s Heliophysics Systems Observatory,” said Jonathan Cirtain, project scientist for Hinode at NASA’s Marshall Space Flight Center.

Different telescopes shoot at different resolutions. SDO is optimized for taking full-disk photos of the sun. Enlarging the spot group where the flare occurred results in a blurry image (left). At right, the Dunn Solar Telescope provides a much more detailed view. The white patch is the flare in near-visible light. Credit: NASA (left) and NSO

“Some of the spacecraft observe the whole sun all the time,” added Cirtain, “but three of the observatories had coordinated in advance to focus on a specific active region of the sun. We need at least a day to program in observation time and the target – so it was extremely fortunate that we caught this X-class flare.”

In NASA’s RHESSI space telescope, which records extreme temperatures on the sun, the flare appears as a series of three hot spots (purple) superimposed on the IRIS image. The two at left are near the surface; the other high above. Credit: NASA

The battery of instruments involved included three NASA orbiting telescopes – the Interface Region Imaging Spectrograph (IRIS); Solar Dynamics Observatory (SDO); Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI); the Japanese Aerospace Exploration Agency’s Hinode; and the National Solar Observatory’s Dunn Solar Telescope located at Sacramento Peak in New Mexico.

A nice summary of observations made by all the telescopes of the March 29 flare

Instruments on the observatories are planned so that each shows a different aspect of the flare at a different heights above the sun’s surface and at different temperatures. Together they can provided a comprehensive 3D view of one of nature’s most powerful blasts.

The images and video record flare material extending from the solar surface called the photosphere (literally ‘sphere of light’) to more than 3,000 miles high (4,800 km) – well beyond the top of the chromosphere, the lowest level of the sun’s atmosphere.

Cutaway showing the different layers of the sun’s atmosphere. Credit: NASA

Chromosphere means ‘sphere of color’ and comprises the realm of the beautiful flaming red prominences see during total solar eclipses. Temperatures there are hotter than the sun’s 10,000-degree F surface, rising from 11,000 degrees to about 36,000 degrees. Hydrogen gas, what the sun’s mostly made of, glows a deep red at these toasty temps.

Once you reach about 1,250 miles (2,000 km) the chromosphere transitions to the much more extensive solar corona. It’s here that the solar wind originates, that stream of subatomic particles – electrons and protons – blown into space at many miles a second. The violence of solar flares can also blast material out of the corona as a coronal mass ejection.

Flares affect all layers of the sun’s atmosphere. With awesome amounts of data in hand from the March 29 solar storm, scientists are now hard at work teasing out a more detailed picture of how a flare gets started and where it goes from there.