Wow, that’s a lot of sunspots! Aurora in the forecast April 19-20

A very busy sun photographed early this morning with NASA’s Solar Dynamics Observatory. Sunspot region 2035 shot off a moderately strong M-class flare on April 16. NOAA forecasters predict a 60% chance for more flares today from one or more of the sunspot groups. Credit: NASA

I can’t recall seeing the sun this peppered with sunspots in a long time. Through the scope this morning I counted nine separate groups. No single spot or group stood out as unusually large, but the combined effect of seeing so many blemishes in one glance made an impression. I encourage you to point your telescope – suitably equipped with a safe solar filter of course – at the sun today to appreciate how fraught with magnetic activity our sun has become.

Each group marks a region on the sun’s shiny outer skin called the photosphere where magnetic energy is concentrated. 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.

A powerful solar flare in sunspot region 2036 captured this morning around 8:30 a.m. CDT April 14 in extreme ultraviolet light by the Solar Dynamics Observatory. Credit: NASA

Energy stored in sunspots’ twisted magnetic fields can suddenly be released in violent, explosions called solar flares. Billions of tons of solar plasma – the sizzling mix of protons and electrons that composes the sun – are heated to millions of degrees during the explosion and rapidly accelerated into space. Radiation from radio waves to X-rays and gamma rays fan out at the speed of light. Fortunate for us, our atmosphere and planetary magnetic field protect us from most of what flares can dish out.

The powerful X4.9 solar flare of Feb. 25, 2014 recorded in six different wavelengths of ultraviolet light. Credit: NASA/SDO

Not everything though. Strong X-class flares can cause radio blackouts, damage satellite electronics and disrupt poorly protected power grids. They also can spark displays of northern lights. An M-class flare from sunspot region 2035 on April 16 may kick off auroras overnight Saturday April 19-20. NOAA forecasters predict a 25% chance of a minor auroral storm.

Video of February’s X4.9 flare shown in multiple wavelengths of light

Conditions are ideal if it comes to pass. Moonlight won’t be a problem and night temperatures are decidedly more pleasant than in February.

Aurora alert for northern U.S. tonight Feb. 27-28

Click image to watch video of the X4.9 flare on Feb. 25 in multiple wavelengths of light / Solar Dynamics Observatory

Lots of movement in the northern lights over Hamburg, Germany this evening Feb. 27-28, 2014. Submitted by Daniel Fischer

A spectacular solar X4.9 solar flare from returning sunspot group AR 1967 on Feb. 25 wasn’t supposed to have much affect on Earth. Surprise! Even though the plasma blast shot off to one side of the sun’s disk, our planet’s magnetic bubble received a glancing blow from the explosion this afternoon. Talk about explosion – swarms of electrons and protons left the sun at an estimated 4.4 million mph!

Still image of the X4.9 flare on Feb. 25. Notice that it’s aimed well off to the left. If it had occurred near the center of the disk, its effects on Earth would be more severe. This flare is the strongest yet this year and one of the strongest in the current sunspot cycle. Credit: NASA

As of 5 p.m. CST, a moderate G2 geomagnetic storm is in progress with strong auroras flaring up over across Europe as far south as southern Germany. Should the activity continue, skywatchers in the northern U.S. and possibly farther south will have a good chance at seeing the northern lights tonight. With no moon present, conditions will be ideal for aurora watching. Start looking as soon as possible after twilight ends this evening.

Click HERE to see the extent of the auroral oval, which will help you determine if northern lights might be visible from your location. I’ll update as needed. Good luck!

A quiet affair. The aurora from north of Duluth, Minn. U.S. Thursday night Feb. 27, 2014. Temperature -30 F. Credit: Bob King

UPDATE 9 p.m. CST: Aurora out here in Duluth as a so-far quiet bright arc low in the northern sky.

Big sunspot convulses but all quiet on the aurora front … for now

Sunspot region 1967 is so big it easily popped into view through a “cloud filter” Sunday afternoon Feb. 2. The group is visible with the naked eye properly shielded by a safe solar filter. Details: 350mm lens at f/11, ISO 200 and 1/2000″. Credit: Bob King

What a crazy sunspot cycle. Weeks go by with only a few tiny spots freckling the sun, then all at once a monster group big enough to swallow 10 Earths rounds the eastern limb and we’re back in business. I’m happy to report we’ve got another behemoth snapping and crackling with M-class (moderately strong) flares. That would be Active Region 1967, the hunk a hunk of burnin’ sun we checked out a few days ago.

NOAA weather forecasters predict an 80% chance of continued M-flares and a 50% chance over the next 3 days for considerably more powerful X-class flares. This sunspot group has a delta classification magnetic field, the Facebook equivalent of “it’s complicated”.

Sunspots are made of a dark umbra and lighter penumbra. Very tiny spots with no penumbrae are called pores. A close up of the sun’s photosphere shows a finely granulated texture. Granules are cells of hot gas about the size of Texas that rise from below, cool and sink. Each lasts from 8 to 20 minutes. Credit: NASA

Sunspots have two parts: a dark core (or cores) called an umbra surrounded by a paler skirt of magnetic energy, the penumbra. They can look impressive like this one, but it’s hard to call a sunspot a “thing”. It’s really more of a location on the sun’s bright white photosphere where bundles of powerful magnetic energy bob up from below the surface and insulate a region of the sun’s fiery hydrogen gas from the rest of the flaming globe.

We’re talking insulate as in staying cool. While the photosphere cooks at around 11,000 degrees Fahrenheit, sunspots are some 3,000 degrees cooler. That’s why they appear dark to the eye. If you could rip them away from the sun and see them alone against the sky, they’d be too bright to look at.

Close up of AR 1967 photographed by the Solar Dynamics Observatory at 6:45 p.m. CST Feb. 3, 2014. The group’s shape reminds me of the Big Dipper. Credit: NASA

A delta-class spot group has umbrae of both polarities, north and south, corralled within the penumbra. Like bringing opposite poles of a two magnets so close they snap together, something similar happens inside delta-class groups. Only instead of a snap, a titanic thermonuclear explosion called a flare goes kaboom.The biggest flares release the equivalent of more than a billion hydrogen bombs.

We thank our lucky stars for the 93 million miles separating sun and Earth. AR 1967 has paraded right in front of our noses as it rotated with the sun. Today it squarely faced the Earth – a good thing when it comes to the particle blasts that fire up the northern lights. Let’s hope it showers us with a magnetic goodness in the coming days. I really miss seeing the aurora. You too?

Big sunspot livens up a quiet sun / Chance for auroras overnight Feb. 1-2

Sunspot region 1967 dominates the solar disk in this photo made late Jan. 31 by the Solar Dynamics Observatory. Credit: NASA

Sunspot group 1967 burst onto the scene on Jan. 28. Now it’s big enough to easily see with the naked eye through a safe solar filter. The group’s twisty, complex magnetic field has already ignited a significant M6 flare on the 30th with a 60% chance for more M-class flares in the next three days.

The expanding cloud of solar plasma called a coronal mass ejection caught blasting away from sunspot group 1967 on Jan. 30 photographed by the Solar Heliospheric Observatory. Credit: NASA/ESA

The Jan. 30 event kicked out a high-speed proton-electron soup called a coronal mass ejection, a part of which will graze Earth overnight tonight (Feb. 1-2) and may spark a northern light display at high latitudes. Of course there’s always a chance southern Canada and the northern border states of the U.S. will see some action, too.

Since there’s been such a dearth of auroras of late, I wanted to share this bit of potentially good news. I’ll post updates if the lights make an appearance.

Why no aurora last night? Here’s the scoop

Maybe you were expecting something more like this last night? Join the club. Credit: Bob King

Did you plan a vigil the past two nights in hope of seeing the northern lights? I know I did. Lost some sleep over it for sure. As it happened, the display never materialized. Yes, the expected brush with particle blast released by the Jan. 7 solar flare did blow by Earth, but only managed to stir up a nice show in Arctic regions like northern Norway and Finland during afternoon hours for U.S. time zones.

Since auroras in that part of the world are as common as doughnuts, I think we can say this outburst was officially a flop.

I spoke with Joe Kunches, space scientist at the NOAA Space Weather Prediction Center, this morning about the matter. When I first rang, he told me he’d have to call back because the staff was just going into a meeting about this very topic. Hopefully no heads rolled.

Kunches described the solar blast as an empty bottle. “There was nothing in it,” he said. Despite the fact that it made a direct beeline for the planet, there was no way for scientists to know the strength and direction of the magnetic field embedded in the particle cloud.”

The Solar and Heliospheric Observatory (SOHO) monitors the sun from the stable L1 Lagrange Point a million miles sunward of the Earth. The green swirls around the Earth represent its magnetic bubble called the magnetosphere. Credit: NASA/ESA/Steele Hill

“The CME (coronal mass ejection) was slower than the model suggested by 8 hours, which sometimes means that it will be weaker than expected,” said Kunches.

“This illustrates our biggest forecasting challenge,” he went on. “We can see the path but can’t know it contains a strong magnetic field pointing in the right direction by the time it arrives at Earth the way a forecaster knows the barometric pressure of a hurricane.”

What happens to the swirling, whirling cloud of subatomic particles released during a flare must rank a close second to chaos itself. Scientists make detailed observation with dedicated space observatories like SOHO, the Solar Dynamics Observatory and STEREO probes and then model the behavior of the incoming particle winds as best they can:

“Even if they’re right when it leaves the sun, there’s no guarantee it will be that way when it arrives,” said Kunches. CMEs can rotate and deform in unpredictable ways. The key to a solid prediction of auroras very much depends on the direction of the magnetic field within the cloud when it sweeps by Earth, a factor called Bz.

The interplanetary magnetic field, created by a wind of solar plasma entwined with magnetic fields, departs the sun in the shape of a gigantic spiral. As waves of varying strength, density and direction pass by Earth, our planet’s magnetic field occasionally hooks up with the sun’s, making auroras likely. Credit: NASA

Embedded within the sun’s plasma swirls are portions of its magnetic field. As that material – called the interplanetary magnetic field (IMF) – sweeps past Earth, it normally glides by, deflected by our protective magnetic field, and we’re no worse for the wear. But when the solar magnetic field points south – called a southward Bz – it can cancel Earth’s northward-pointing field at the point of contact, opening a portal. Once linked, the IMF dumps its baggage of high-speed particles into our atmosphere to light up the sky with northern lights.

The Jan. 7 solar gust arrived at Earth with a northward pointing Bz. With no coupling, nothing happened. Perhaps you’ve watched the real-time red trace on the ACE satellite’s Bz read-out. For most of the past two days that squiggly line has been “flat as a pancake” as Kunches put it, which did not bode well for auroras. At any time it could have dipped south but never did.

Click to watch a video of the solar wind linking up with Earth’s magnetic field behind the planet, sparking a particle cascade and auroras in our upper atmosphere.

While no method is absolutely guaranteed, I recommend the following sites to check before you get in your car and drive 100 miles to see an aurora:

* ACE Dynamic Plots – The red trace for Bz is the one you’re interested in. If the line dips well below the centerline to -10 or lower, auroras may be likely.
* Ovation Aurora - Simulation of the auroral oval (extent of aurora) based on live satellite data. Pay attention to the location of the red curve showing the southern extent of auroral visibility.
* Kp index – magnetic activity indicator updated every 3 hours. A yellow bar (Kp=4) is a good sign aurora might be visible from the northern U.S. and southern Canada. A red bar (Kp=5 or higher) indicates a larger storm and more extensive aurora.

By the way, Kunches says that the CME has blown by and doesn’t expect any northern lights for tonight, so catch up on your sleep. In the meantime, put on your philosophical cap and reflect about how much we really don’t know about the world. Always a great motivation to learn more.

Aurora Alert! – Good chance for northern lights tonight and tomorrow Jan. 8-9

A bright curtain of aurora drapes the northern sky two summers ago. Credit: Bob King

It’s not often you see “major” and “severe” geomagnetic storms in the space weather forecast, but here it is:

“Quiet to severe storm levels on day one (9 Jan.), unsettled to severe storm levels on day two (10 Jan.) …”

These dates are Greenwich time so Jan. 9 means sometime overnight tonight (Jan. 8-9) for U.S. and Canadian time zones. All this excitement is brought to you by the current huge sunspot group known as Active Region 1944, which contains one of the biggest sunspots seen in years.

Big sunspot group 1944 at 4:45 p.m. CST today. Credit: NASA

The entire works spans some 125,000 miles (200,000 km) or more than 15 times the size of the Earth. It’s spawned multiple M-class (moderate) flares and at least one X-class (strong) flare in the past couple days, sending high-speed streams of protons and electrons in Earth’s direction.

There’s an 80% chance of additional M-class and 50% chance of X-class flare from this very active group in the coming days. Sunspot groups are regions on the sun’s surface where magnetic energy is strongly concentrated like a giant bar magnet with north and south poles. In simple groups, the positive and negative magnetic poles are separated from one another and not likely to come in contact and cause trouble. Astronomers say these groups have a “beta” magnetic classification.

The X1-class flare that popped off earlier yesterday Jan. 7 in the big sunspot group cut loose a large, high-speed cloud of particles called a coronal mass ejection. Some of that material will start arriving in Earth’s vicinity late tonight. Click to see animation. This photo was taken with the SOHO coronagraph. Credit: NASA/ESA

Huge complicated groups like 1944 have a beta-gamma-delta magnetic field where spots of opposite polarities lie near one another with no clear division between them. This is where things get volatile. The more complicated a sunspot group’s magnetic field becomes, the greater the potential for magnetic mischief. Opposite polarities can interact in the churnin’, burnin’ solar soup and spawn strong flares.

When those speedy particles arrive and hook in to Earth’s magnetic field, which we dearly hope will happen, they spiral toward our magnetic poles, crashing into air molecules and exciting them to fluoresce as northern lights.

Let’s hope that transpires either tonight or tomorrow night. The moon – now just over half – won’t be enough to wash out the sky like a full moon would, and it sets just after 1 a.m., leaving a completely dark sky. Cross your fingers and get ready – the sky may go electric tonight. It’s clear here in Duluth, Minn., so I’ll be monitoring and updating.

UPDATE: 9:30 a.m. CST today: Expected northern lights didn’t happen overnight. Nothing seen from Duluth, Minn.. Chances are even better for auroras to break out tonight, so don’t give up the vigil. I’ll update later today.

Boo! Ghostly auroras possible on Halloween

A farewell X2-class flare from big sunspot region 1875 as it departed the sun’s face late Tuesday afternoon Oct. 29. Although it blasted out a massive cloud of electrons and protons (see below), the material doesn’t appear to be directed toward Earth. Credit: NASA

Auroras on Halloween? I can’t think of a better fit than the spooky quavering of northern lights. I’m happy to report there’s a real possibility that skywatchers in the northern U.S. and southern Canada might share their treat or treating with an ominous green arc hanging over the northern horizon.

Aftermath of the X2 flare from sunspot region 1875 – a massive burst of particles lifts off the sun to the right. Photo made with a coronagraph, which blocks the sun so astronomers can study the sun’s corona or atmosphere. Credit: NASA / SOHO

Space weather experts are forecasting a 20 percent chance of minor geomagnetic storms and accompanying auroras for mid-latitudes through tomorrow night. Northern lights were expected this past weekend from the combined effects of several flares. The continuing parade of large sunspot groups and their associated solar flares have sent several particle blasts in our direction. None ever found a way past Earth’s magnetic defenses to spark a display of northern lights.

Let’s hope that changes on Halloween. That’s when the effects of a M4-class (medium-sized) flare from sunspot region 1882 will arrive. Clouds of high-speed subatomic particles and tangled magnetic fields lofted into space from the explosion are on the way; be on the lookout tonight and tomorrow night. All the aurora indicators have been very low the past week, but I noticed today that the Kp index has been ticking up, a good sign.

Waves of CME (coronal mass ejection) material sweep past Comet Lovejoy earlier this week in an animation of STEREO space probe images compiled by Alan Watson.

Comet Lovejoy, now visible in binoculars in the morning sky, has recently grown a narrow tail of fluorescing gas called an ion tail. Like a windsock, an ion tails wiggles and warps according to changes in speed and intensity in the wind of particles released by the sun.

Kinking and bending in the ion tail of Comet Lovejoy seen here on Oct. 29 may be result of the passage of waves of solar particles entwined with magnetic fields. Credit: Gerald Rhemann

All those recent coronal mass ejections sent waves of particles across the solar system, some of which flowed right across the comet and may have caused a twist in its tail recorded by amateur astronomers earlier this week. The animation, compiled by Alan Watson from images taken by NASA’s STEREO sun-watching spacecraft, show the waves very clearly.

For more on finding Comet Lovejoy and the three other bright-ish comets in the morning sky, please see my article Four Comets Haunt the Halloween Dawn on Universe Today. Detailed maps are included.

Forecast: Explosive sunspots with a chance for auroras tonight, this weekend

Venus shines above a beach in Maui, Hawaii late last week. Island of Lanai in the distance. Waves are lit by firelight. Credit: Bob King

Just returned from a wonderful trip to the island of Maui in Hawaii where Venus shines high in the western sky after sunset and a handful of professional observatories track the comings and goings of wayward satellites, comets and asteroids from a dormant volcano 10,000 feet above the Pacific Ocean.  I’ll have more Maui astronomy to share with you soon, but for the moment, let’s focus on the sun.

Views of the sun in a variety of wavelengths of light showing the flares from sunspot groups 1875 (top right bright patch) and 1877. Solar Dynamics Observatory 

More than one sunspot group has been blasting stuff in Earth’s direction this week. The two largest sunspot groups – active region 1875 and neighboring 1877 – both have complex magnetic fields that have spawned hefty flares. 1875 kicked out a medium M4 flare on Oct. 22 while region 1877 upped the ante with a powerful M9 class flare Wednesday evening CDT.

The sun late this afternoon CDT Oct. 24 taken by the Solar Dynamics Observatory. Both regions 1875 and 1877 are big enough to see with the naked eye with a safe solar filter. Credit: NASA

The M9.3 is just below the X-class flare level, the most energetic category.  The material the explosion shot into space appears to be directed toward Earth with a possible arrival this weekend. Should northern lights materialize, a late-rising third quarter moon won’t spoil the show.

With this recent resurgence in solar activity after a summertime lull, things look promising. Space weather forecasters are calling for a 15 percent chance aurora overnight tonight for mid-northern latitudes overnight from earlier coronal mass ejections. Keep a watch – I’ll be out there too.

Chance for flares from bad-boy sunspot group 1875

Today’s sun is speckled with sunspot groups including region 1875 which is approaching the center of the disk. M-class flares are possible from the region, which if timed right, could up our chances for seeing auroras later this week. Credit: NASA / Solar Dynamics Observatory

We’ve been a dry spell for auroras the past couple weeks, but that could change if a large sunspot group now crossing the solar disk continues to grow and become more magnetically active.

Active region 1875 has no particularly large spots, but it does cover a lot of area and contains a complex beta-gamma-delta magnetic field. In ordinary language, it means that positive and negative magnetic poles are very close one another in the group. If opposite poles meet on the sun’s churning surface, vast amounts of energy are released in large flares, flinging clouds of electrons and protons toward Earth in a coronal mass ejection.

Space weather forecasters give the group a 30 percent chance of producing an M-class or medium-sized flares. These babies can cause radio blackouts in Earth’s polar regions and stir up minor to modest auroras. Region 1875 harbors a smaller chance for kicking out an X-class flare, the most powerful category.

We’ll keep an eye on the sun in the next few days to see what happens. You can check HERE for the current flare and aurora forecast. Amateurs with solar-filter equipped telescopes will have a good week of sun watching with many sunspot groups to enjoy.

A 3rd X-class flare rocks the sun

The latest X3.2 flare in far ultraviolet light at 8:16 p.m. CDT Monday evening May 13 (May 14 Universal Time) photographed by the Solar Dynamics Observatory. Credit: NASA

Solar activity’s been rising like nobody’s business. Two of the year’s most powerful flares fired off from the sun’s backside late Sunday and at least 8 spot groups speckle the sun’s white-hot surface today.

Another ultraviolet picture of the sun taken by NASA’s STEREO Behind spacecraft late on May 13. The flare looks like a giant spike because the brilliance of the explosion saturated the camera sensors. STEREO Behind orbits well behind Earth and sees a part of the sun’s backside not visible with Earth-based telescopes. Click to learn more about the STEREO probes. Credit: NASA

Now we can add a third strong X-ray class flare, an X3.2 that spewed a vast cloud of high-speed solar gases called a coronal mass ejection (CME). Lucky for Earth, it was directed – as the other flares were – away from our planet off the eastern edge of the sun’s disk.

The most energetic flare measured in the modern era occurred on November 4, 2003 during the last solar maximum. No one knows how truly strong it became since the sensors topped out at X28. But any flare in the X-category can affect everything from GPS satellites to radio communications, satellite electronics and even fry poorly-protected power grids.

The sun in normal white light late Monday with sunspot groups labeled. Region 1748 – site of the strong flares of the past few days –  is just coming into view at far left. Credit: NASA

Solar flares typically occur in sunspot groups where magnetic energy is concentrated. The  solar surface, which bubbles and churns like a monster pot of hot oatmeal, brings opposite magnetic fields (north and south poles) in contact with one another. When they reconnect, the sudden release of energy heats solar gases to many millions of degrees and blasts billions of solar electrons and protons into space as a CME.

The amount of energy from a big flare like the ones we’ve seen recently equals millions of thermonuclear (hydrogen) bombs.

A healthy CME (coronal mass ejection) in the wake of the most recent X3.2 flare late Monday. This photo was taken by the Solar and Heliospheric Observatory which uses a special mask to block out the bright sun to better photograph it outer atmosphere. Credit: NASA / ESA

The sunspot group responsible for all the current feistiness goes by the name of 1748; it’s just coming around to the sun’s front side. Though highly foreshortened because we’re peering at it along the extreme edge of the sun, you can tell it’s a big one. Let’s hope it kicks and sputters its way to a northern lights display without any serious damage to our favorite toys.