Quiet aurora tonight Aug. 27-28

A lquiet auroral arc topped by a faint pink band glowed softly in the northern sky tonight at 10:30 p.m.. The bright star at right is Capella in the constellation Auriga. Credit: Bob King

After Wednesday morning’s fine display, the current wave of magnetic activity is subsiding but not without leaving a tasty leftover. A low, quiet arc has hovered over the northern horizon all evening. Maybe it will take off again as the aurora did this morning, but the forecast indicates a gradual decline in activity overnight.

Map showing the extent of the auroral oval early this Thursday morning August 28. The arc in the photo above is the edge of the large, permanent oval of aurora centered on Earth’s geomagnetic pole. In this map, which is based on satellite data, you can see that the edge of the oval lies right at Minnesota’s northern border. Click to see the current oval. Credit: NOAA

If you live in in the northern U.S. away from city lights and enjoy the subtle side of nature, you’ll find tonight’s aurora suitable for contemplation.

Beautiful rays of aurora dapple the dawn sky

At 4:45 a.m. CDT this morning (Aug. 27) spectacular rays erupted from a low, bright green arc and paraded across the northern sky. Credit: Bob King

Maybe it’s because of the name aurora, which means ‘dawn’, but that’s exactly when the northern lights put on one great show this morning. With clouds constantly a bother this late summer, many of us have been thwarted in viewing all manner of conjunctions, comets and moonrises. Not this morning. I was determined to see Comet Oukaimeden near Orion just before dawn. And that’s exactly how I happened to be up to catch a surprisingly fine aurora.

A striking green arc perforated by many needle-like rays. Credit: Bob King

One of the keys to maximizing enjoyment of the aurora is to have a place you can get to with a low northern horizon. At least from mid-northern latitudes, lots of activity often occurs very low in the northern sky.

High speed electrons from the sun spiral down individual magnetic field lines in Earth’s magnetic bubble called the magnetosphere to create multiple parallel rays when they strike oxygen and nitrogen atoms in the upper atmosphere. Credit: Bob King

We were already primed for northern lights because of the NOAA space weather forecast, so when I looked out the window at 4 a.m., there they were.

I jumped in the car and sped to a country road not far from home. Arriving around 4:30 a.m. several pale green arcs snaked across the north, and within minutes they erupted with massive parallel rays. To the eye, the tall rays were colorless, but they loved the time exposure afforded them by the camera.

The pictures were taken using a 17mm lens at f/2.8, ISO 800 and exposure times around 15 seconds.

While I did get to see my comet in the nick of time, the northern lights made it more than worth my while. I hope you got to see them, too.

Jupiter (lower left next to the star Delta in Cancer) and Orion (upper right) sparkle in the dawn sky over Duluth, Minn. Wednesday morning. Credit: Bob King

The display continued deep into twilight and no doubt carried into darker skies farther west of my location. There’s still a possibility for minor auroras early tonight. I hope so. Two 4 a.m. stints in a row would kill me.

Surprising aurora puts on great show last night

Auroral arcs are topped by red rays light up the northeast while the moon (0verexposed) and Jupiter shine off to the west in this photo taken last night over a small lake north of Duluth, Minn. Both moon and aurora light are reflected in puddles on the ice. Credit: Bob King

No, it wasn’t in the forecast but just the like real weather, the unexpected happens. A change in the “magnetic direction” of the wind of particles from the sun called the solar wind from north to south made all the difference. Earth’s magnetic field points northward. When the field associated with a batch of plasma from the sun points southward, as it did beginning early yesterday evening, there’s a good chance it will link into our field and ultimately allow those particles passage into our upper atmosphere.

A large red patch briefly glowed above the bright green arc around 11:15 p.m. last night May 3. The color was dimly visible with the naked eye. Credit: Bob King

Spiraling down magnetic field lines like firefighters on a firepoles, billions of tiny solar electrons strike oxygen and nitrogen molecules in the thin air 60-125 miles up. When the excited atoms return back to their normal rest states, they shoot off niblets of green and red light that wash the sky in multicolor arcs and rays.

The whole northern sky lit up with green and red rays earlier this morning. While the green color was easy to see, the red was very pale. The human eye is much more sensitive to green light than red, one of the reasons why the aurora rarely appears red except in a camera during a time exposure. Credit: Bob King

Nothing in the space weather forecast would have led you to believe northern lights were in the offing for mid-latitude skywatchers last night. Maybe a small possibility of a glow very low on the northern horizon. Maybe. Instead we got the full-blown show with auroras of many forms jumping, glowing and dancing all night long. When I finally hit the hay at 4 a.m. flames of moderately bright aurora still rippled across the north.

So what about tonight? Just like last night, there’s only a 5% chance of a minor storm. Like I always say, take a look anyway, because nature always has a surprise or two up her sleeve.

Aurora out tonight May 3-4 over northern U.S.

There may be a lot of trees in this view but they don’t hide the fact that the northern lights are visible tonight right now (10:30 p.m. May 3) low in the northern sky. Take a look if it’s clear by you. Credit: Bob King

(UPDATE May 4: Click HERE to see what a fine show the aurora gave us overnight.)

Watch for auroras tonight. 15 minutes ago, a bright arc lit up in the northern sky here in Duluth, Minn. No way to know if it will fade or go wild, so be sure to take a look if it’s clear tonight. The magnetic field in the solar wind tipped southward this evening, weaseling a connection to Earth’s own magnetic domain and sparking a small display of northern lights. I’m headed back out for more. Good luck – let’s hope it continues.

Chance again tonight April 20-21 for northern lights

Very nice aurora north of Duluth about 10 p.m. Sunday night. The rays were intensely colorful in the camera but much paler to the eye. Credit: Bob King

There’s been some action on the aurora scene today. A coronal mass ejection from the sun blew by Earth this afternoon and sparked auroras over northern Scandinavia and other locations in northern Europe where it was dark at the time. There’s continues to be a fair chance for minor auroras over the northern U.S. tonight (Sun. April 20-21), so you may want to be on the lookout. Check the Ovation Aurora site to see the extent of the aurora in near real time.

Curious crossing of colors – tall pink rays in front of a low green arc.  Amazing! Credit: Bob King

UPDATE 1 a.m. April 21 — The northern lights made a decent showing over northern Minnesota between the end of twilight around 9:30 p.m. until about 10:45 p.m. Sunday night. Lots of slow-moving, “lazy” rays to 50 degrees across the north. Extremely colorful in the camera but pale pink-purple to the naked eye at best. Hope you got to see the show.

Occasional rays formed that glowed for many seconds at a time before fading away appeared in the northern sky. Credit: Bob King

Northern lights alert Feb. 18-19 – They’re out there!

A complete surprise. I was out with my astronomy class this evening and the northern lights suddenly showed around 8:30 p.m. Sure wish I’d brought a tripod. This photo taken on a monopod. Credit: Bob King

It wasn’t in the forecast but then sometimes the best things aren’t. Let’s just say the aurora is cooking away very nicely across the northern sky with rays to 40 degrees high as of 10 p.m. Some nice curtains near the horizon and even color. I’ve seen obvious pink tops on some of the taller, brighter rays.

The aurora died back around 9:30 p.m. but surged again after 10 o’clock. This photo was taken at 10:30 p.m. CST. when much of the northern sky showed good activity. Credit: Bob King

Even though the waning gibbous moon is up, if you have a chance, check out the northern sky. Moonlight lowers the contrast of the display some, but once your eyes are dark-adapted, there was lots to see (at least from 8:30-10:30 p.m.). Hopefully the display will continue long into the night.

Aurora in the northeastern sky around 10:15 p.m. tonight Feb. 18, 2014. Credit: Bob King

An unexpected passage of a high-speed solar wind gust that happened to be pointing in the right magnetic direction (south Bz) hooked into Earth’s protective magnetic field and sparked the display. The Kp index, which slumbered all day in the low activity, green zone shot up into the red at Kp=5 during the early evening.

You can stay in touch with what the aurora’s doing overnight by clicking on the Kp link above as well as the Ovation auroral oval site which shows the extent of the aurora.

Good luck in your viewing!

Extent of the aurora oval around midnight CST Feb. 18-19. The map, based on satellite data, indicates that aurora should be visible at least across the northern tier states. Credit: NOAA

UPDATE 11:45 p.m. CST: Lots of rays and rayed arcs appearing across the north-northeast up to 45 degrees high. The moon is up higher now reducing contrast but still a fine show.

UPDATE 12:10 a.m. Feb. 19 – Intense, thick green arc slung across the bottom half of the northern sky. Pulses of fainter “flaming” aurora rising to the zenith. Sense that a bright eruption might happen soon.

A singular, colorful auroral ray. Its pink top was obvious with the naked eye. Credit: Bob King

UPDATE Feb. 9 a.m. : The aurora lasted the entire night and peaked around 2-3 a.m. It was still rolling in morning twilight.

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.

Keep your eyes open for aurora tonight Nov. 8-9

Big sunspot group 1890 has rotated into an ideal position to fling solar stuff in Earth’s direction should its flaring ways continue. Credit: NASA/SDO

There’s been a jump in auroral activity tonight possibly related to recent flares from the large sunspot group numbered 1890. This Jupiter-sized group has erupted with several X-class flares this week. Starting yesterday and continuing for the next few days the region will face Earth; with more M and X-class likely that means continuing chances for more blasts on the way. If you have a safe solar filter I encourage you to give 1890 a look – it’s big enough to see with the naked eye and looks splendiferous in a small telescope.

The aurora oval has expanded southward tonight toward the northern states and may possibly bring northern lights to the northern states and southern Canada. This map shows the oval around 11 p.m. CST. Click to see the current oval. Credit: NOAA

If monster sunspots weren’t enough, strong solar particles winds flowing from a large coronal hole earlier in the week could reach Earth this weekend. Whatever the cause, the potential for aurora tonight exists, since the ACE spacecraft indicates a southward direction in the magnetic field of the material in Earth’s vicinity right now (11 p.m. CST). A southward “Bz”, as it’s called, provides an ideal linkage with Earth’s northward pointing field by creating a “hole” through which solar particles can sneak by the planet’s magnetic defenses. Once inside the planet’s inner magnetic sanctum called the plasma sheet, auroras are more likely.

If it’s clear at your place tonight take a look at the northern sky for any unusual glows or arcs. It could be the start of an auroral display.

Spectacular aurora! Stay tuned for more

The aurora before midnight was soft-edged and billowy. When this photo was taken shortly before 3 a.m. today, the entire northern sky undulated with tall rays. Credit: Bob King

The blast of solar wind that raked over Earth’s protective magnetic bubble overnight has subsided for the moment, but there’s still a possibility for more auroras tonight. Be on the lookout at the end of evening twilight until around midnight.

A wispy, comet-like aurora high in the southern sky next to the Square of Pegasus around 2 a.m. Credit: Bob King

Speaking of which, there wasn’t much time for sleep last night.  I tried to wind it up, but couldn’t resist checking in on the aurora one more time. Before I knew it, it was 3 a.m. By then undulating rays stretched to the zenith.

That’s how the aurora nails you. It begins slowly then ups the ante. Just when you think a display’s beginning to subside it rages and paints the whole sky. What’s a human to do but look up with mouth agape?

Separate “pieces” of aurora like these red and green patches in the constellation Cetus appeared off by themselves far away from the main display around 10:30 p.m. last night. Credit: Bob King

Early this morning geomagnetic activity reached the G2 moderate storm level on the NOAA scale that ranges from G1 (minor storm) to G5 (major storm). G2 storms are accompanied by auroras visible as far south as New York and fading of shortwave communications. Long-duration G2s can even cause damage to power transformers at high latitudes.

This large, north-south filament tens of thousands of miles long was responsible for last night’s auroral storm. Credit: Big Bear Solar Observatory

There’s no doubt where all this came from: the sun. Last week the sun grew an enormous dark moustache called a filament. Filaments are long troughs of cool, dense hydrogen gas held aloft in the sun’s atmosphere by solar magnetic fields. Against the sun, they’re dark and seen in silhouette, but as the sun rotates, filaments eventually reach the edge of the disk and stick out as brilliant red flames called prominences against the blackness of space. They’re what makes that beautiful red fringe around the sun during a total solar eclipse.

Now-you-see, now-you-don’t. By Sunday evening the shattered bits of the filament were gone , headed toward Earth and acrossthe solar system. Credit: Big Bear Solar Observatory

Filaments normally hang out like tourists in hammocks along a beach front, but every so often those magnetic fields become unstable and either eject the filament or it simply collapses. A portion can “rain” back down to the sun’s atmosphere and reform as a new filament, but sometimes they get shot straight into space or collapse, hurling a coronal mass ejection toward Earth.

Filament eruption caught by the Solar Heliospheric Observatory on Sunday evening Sept. 29 around 6:30 p.m. CDT. Credit: NASA/ESA

That’s what happened Saturday evening Sept. 29 CDT. What had been a peaceful filament minding its own business suddenly got the magnetic boot. The eruption sent bits of pieces of the hot solar gas at hundreds of miles a second across the solar system. Some of that material – what once rested quietly in the sun’s atmosphere – bee-lined into Earth’s upper atmosphere and set off an auroral storm. Pretty cool.

A bright, pale green arc gathers strength low in the northern sky around 11 p.m. last night. Credit: Bob King

I hope some of you got to see it. If you didn’t, the space weather experts predict more for tonight. Despite the U.S. government shutdown, the Space Weather Prediction Center remains open. Click the link to get the latest synopsis and forecast. Good luck!

(Update 10 p.m. CDT: Auroras kicked up again during late afternoon and early evening hours Oct. 2 across the Americas. Observers in Europe, where it was dark, likely had a nice show.)