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.

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.

Big Sunspot Group Turns Earth’s Way / Comet ISON Photo a False Alarm

Sunspot region 1944 has a complicated beta-gamma magnetic field making it prone to producing flares. Photo taken by the Solar Dynamics Observatory at 9:15 a.m. CST today. Click to enlarge. Credit: NASA

We knew it was big even when it rounded the sun’s limb two days ago, but now that sunspot group 1944 has rotated into clear view, we can truly appreciate its enormity. Based on my rough estimate, the largest spot in the group is now easily 40,000 miles across or five times the diameter of Earth and one of the largest of the current solar cycle.

Sunspot group photographed through a “cloud filter” with a 300mm lens this morning Jan. 4, 2014. With a safe solar filter, the group is big enough to see with the naked eye. Credit: Bob King

The group has banged off several moderate M-class flares in the past 24+ hours. NOAA space weather forecasters are calling for a 75% chance of additional M-flares and a 30% chance for powerful X-flares in the days ahead.

Given that the group’s predicted arc across the rotating sun will soon place it squarely in Earth’s direction, we hope that it continues to percolate with flares, potentially sparking auroras in the nights ahead.

Earth and moon size illustration compared to today’s photo of the large sunspot group. Credit: NASA

Using a #14 welder’s glass I could easily see the sunspot region as a dark dot in the lower right corner of the sun with my naked eye this morning. If you have a safe solar filter or a telescope equipped with one, take a look and be impressed.

The sausage-shaped glow running from upper left to lower right in the left-side negative image was suspected to be Comet ISON’s remnant. Photo at right shows nothing at ISON’s position on Jan. 1, 2014. The blue dot marks the predicted position of the comet; the green type gives the names of stars. Click for more images and information. Credit: Hisayoshi Kato

In other news, Japanese amateur astronomer Hisayoshi Kato made a deep image of Comet ISON’s location on December 29 using a 180mm f/2.8 telephoto lens near the Mauna Loa Observatory in Hawaii, recording a possible sausage-shaped dust remnant. Because long time exposures and electronic image processing can sometimes introduce artifacts into an image, Kato photographed ISON’s position again on Jan. 1 but came up empty handed.

No similar remnant stood out on the second try indicating his original photo didn’t capture the comet after all. Some of us were hopeful he had. So what is that dusty sausage? Possibly a strand of the Integrated Flux Nebula, a flock of dust clouds threading the galaxy that glow not by the light of a nearby star(s) but instead from the integrated flux of all the stars in the Milky Way. Think of it as stellar light pollution.

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.

Aurora encore may follow July 4 fireworks

July 4th fireworks at Duluth, Minnesota’s Bayfront Park. Credit: Bob King

Happy Fourth of July! I hope your day explodes with enjoyment.

Aurora time-lapse

Just don’t go to bed after the fireworks show before checking the northern sky. NOAA’s space weather prognosticators expect a small auroral storm to begin sometime tonight and continue through tomorrow night. There’s a 20% chance we’ll see action at mid-northern latitudes and a 60% chance at high latitudes, where one wonders if any auroras are seen to advantage this time of year. North of about 49 degrees north latitude, twilight lingers all night long during the summer months.

The forecasted northern lights are brought to you by a slower moving coronal mass ejection, a blast of particles from the sun usually caused by the explosive power of a solar flare.

Neighboring sunspot groups 1785 and 1787 photographed this morning with NASA’s orbiting Solar Dynamics Observatory. Credit: NASA/SDO

We may not have to wait too long for the next eruption. Sunspot group 1785, which rotated onto the sun earlier this week, is a large, complicated magnetic mess and harbors the energy to kick out powerful M-class flares. The sun’s rotation will bring it forward to face Earth more directly in the days ahead increasing the chances for more auroras.

M1.5 flare from sunspot group 1787 as it rounded the eastern limb of the sun early on the morning of July 3. Credit: NASA/SDO

Not far behind, sunspot cluster 1787 put on its own fireworks show when it first rotated around the sun’s limb early Wednesday morning, greeting astronomers with a moderate M1.5 flare.

How the sizes of Earth and moon compare to sunspots. Even an Earth-sized spot requires a telescope to see. The leader spot in the group 1785 is at least 3x larger than our planet. Credit: NASA

The big spot in 1785 is now large enough to see with the naked eye using a safe solar filter – I easily spotted it this morning as tiny dark fleck in the sun’s southeast quadrant. Sometimes we forget how big sunspots truly are. What looks like a tiny dot in a small telescope is about as big as the moon; Earth-sized spots are larger but ordinary by solar standards. This morning’s behemoth was easily thrice our planet’s diameter, and the group it belongs to spans some 8 Earth diameters.

A sunspot’s dark tone is deceiving. They only look that way because they’re 3,000 degrees cooler than the 11,000 degree photosphere, the glaring white “surface” of the sun. If we could remove the spots and see them alone against the black backdrop of outer space, they’d be much too bright to look at safely. Their size hints at the true vastness of the sun, an 863,700-mile-wide (1.4 million km) sphere of incandescent gas 4 times hotter than a handheld sparkler.

Morning aurora topped off by avian cheer

A pretty series of rays sprouts above a pair of green arcs this morning around 3 a.m. CDT. Photo: Bob King

I got up for the stars but stayed for the birds. Clear skies overnight allowed for a look at a surprise aurora display, comets PANSTARRS and Lemmon, a handful of spectacular Eta Aquarid meteors and an attractive lunar crescent early this morning.

Three images from NASA’s Solar Dynamics Observatory were combined to create this spectacular view of last Friday’s flare. Credit: NASA

No auroras were predicted and true-to-forecast all looked quite at least through midnight. But at 2:30 this morning a bright green band spanned the northern horizon punctuated by one, two and occasionally an entire series of faint, rosy rays.

Sunspot group 1734′s largest spot – at left – is several times the diameter of Earth. This photo was taken this morning May 6, 2013. Credit: NASA

Expect more excitement courtesy of our parent star. Last Friday, a big flare erupted along’s the sun’s eastern edge, hurling a dragon-like tongue of incandescent hydrogen gas 120,000 miles (193,000 km) above the surface. Although this storm wasn’t directed toward Earth, the large sunspot group 1734 is currently nearly face-on to the planet and has the potential for strong flares. Cross your fingers.

A bright Eta Aquarid streaks across the northern sky and aurora this morning around 2:45 a.m. Photo: Bob King

I had planned to look at a variety of objects in the telescope but kept getting “distracted” by both the northern lights and regular appearances of incredibly fast, long-trailed meteors streaking across the northern sky from the east – Eta Aquarids.

Because the shower has a broad peak I encourage you to go out for a look yourself. Being so far north, I figured only a few might be seen here in Duluth, Minn. but was happily proven wrong. Had I simply sat in a lawn chair and stared skyward I’m certain I would have seen many more. Click HERE for more on the shower and how to view it.

A wide-field photo of Comet C/2011 L4 PANSTARRS shot on May 4, 2013. The comet is oriented the way it would appear shortly before dawn with the anti-tail pointing down and broad dust fan opening to the left. Credit: Joseph Brimacombe

Let me tell you about Comet PANSTARRS. In 10×50 binoculars I was surprised by how much there was to see under a dark sky. The V or fan-shaped tail spread is still obvious marked at its base by the small, brighter comet’s head. A second, straight anti-tail (debris left by the comet along its orbital path) stuck out like a pinkie finger from one side.

I estimated the whole works measured 1 degree or two full moon diameters across. While faint and smoky-looking at magnitude 7, the comet was very easy to pick out. In a 15-inch telescope PANSTARRS and its dual tails were brighter and better-defined; a tiny star-like nucleus peeped through the gases and dust concentrated in the its head. Very beautiful.

A morning topped off by the crescent moon is never wasted. Photo: Bob King

On to Comet Lemmon. I didn’t see it until 4 a.m. when dawn’s first light had already put its pale stamp on the eastern sky. I found it with difficulty in binoculars as a small, dim soft patch of light below the lower left star in the Square of Pegasus VERY low in the northeastern sky. It’s about as bright as PANSTARRS but low altitude and the onset of twilight combined to make it look fainter. In the scope, Lemmon was a big pale green fuzzball with a hint of a tail pointing southwest. Care to find it yourself? Here’s a map.

Wherever you are, enjoy the coming nights. If the moon’s your thing, an even thinner crescent will rise an hour before sunrise tomorrow in the east. Check for northern lights before you turn in tonight and use the map from yesterday’s blog to try your luck at Comet PANSTARRS … one last time.

 

A sunny slant of view on Earth Day

A halo and circumscribed halo (upper bright saggy arc) around the sun this morning. Both are formed when light is bent or refracted through pencil-shaped hexagonal ice crystals. Photo: Bob King

Happy Earth Day! What a great planet to call home. Situated in our sun’s habitable zone and endowed with life and sweet pleasures, we know of no where else like it. I wouldn’t trade this blue gem for all the planets of Star Trek.

The sun photographed by NASA’s Solar Dynamics Observatory earlier this morning April 22. The large sunspot group at upper right can be glimpsed with the naked eye only through a safe solar filter. Click to enlarge. Credit: NASA

The sun broke through morning clouds today with two pleasant surprises – a colorful circumscribed halo caused by light refracted through billions of microscopic ice crystals in high cirrostratus clouds, and a pair of naked eye sunspots.

Through a safe solar filter, I spied two side-by-side black dots in the upper right (northwest) quarter of the sun.

High-resolution closeup of sunspot group 1726. Sunspots are cooler regions of concentrated magnetic energy on the sun’s surface. They usually have two parts – a dark, inner umbra enclosed by a lighter penumbra. Credit: NASA

They’re part of the large sunspot group 1726 that today spans more than a dozen Earth diameters (approx. 100,000 miles / 160,000 km). The group spawned a few flares, including a moderately strong M-class flare earlier this morning, and holds the potential for more.

Two cool snowpeople catch some April rays last week in Duluth, Minn. Photo: Bob King

In April the sun’s slant in the sky is the same as it is in mid-August, high enough to feel on your cheeks when you walk out the door. It brings welcome relief to some of us still mired in winter with several feet of snow piled up in the yard. The angle of the sun in the sky has much to do with the amount of heat our planet receives and the global climate.

The overhead sun covers a smaller area of ground with the maximum amount of energy (left). At right the sun is shown in winter when its lower angle spreads its light over a larger area with a loss of 100 watts of energy. Result? Colder weather. Credit: Randy Russell / windows2universe.org

If Earth were a gigantic flat disk instead of a sphere and had no atmosphere to filter sunlight, every square meter of ground would receive 1,368 watts of solar energy. Our planet’s spherical shape spreads the sun’s light out over a larger area, diluting the energy received to 342 watts. The atmosphere also filters out a small amount.

A different view of the sun’s angle in winter versus summer and its seasonal energy footprints.  Credit: Nicholas M. Short

When the sun is nearly overhead, as it is during summer, we get the full wattage and really feel the heat just like you would standing next to a 342 watt light bulb. In winter, the sun shines on the planet at a lower angle and its light spreads out broadly across the ground.

Since the amount of energy it’s beaming our way is constant, if it’s spread over a larger area, it becomes less concentrated and weaker. That’s one big reason why winter’s so cold – a lower sun means the intensity (energy) of sunlight is reduced. Without the customary heat to warm air and ground, rain becomes snow and accumulates.

The atmosphere also plays a part. In winter, the low sun shines spends much of the day shining through the lower levels of the atmosphere, where the air is thicker and dustier. Some of that light gets absorbed and some reflected away from Earth, further cooling the season.

Today’s angle suits me just fine. When I walked outside I felt the sun right away and knew it would be good day to celebrate another day of life on the planet. Wishing the same for you.

Fingernail moon, aurora watch and Comet PANSTARRS made easy

The lunar crescent ascends the western sky over the next few nights dropping by two star clusters and one bright planet. The map shows the sky about an hour after sunset. Maps created with Stellarium

The moon has returned to sweeten the evening. Watch for a thin crescent low in the western sky tonight below the Seven Sisters star cluster. Tomorrow it moves upward, thickens a bit and shines near the V-shaped Hyades star cluster. Topping off the weekend, the crescent will stand just 2 degrees left of the planet Jupiter Sunday. If there ever was a gift that keeps on giving, it’s the moon.

To find PANSTARRS at dusk, use binoculars or a telescope and face northwest about 90 minutes after sunset. Look for the bright zigzag of Cassiopeia, point your instrument at the brightest star nearest the comet and “sta hop” in its direction. This map shows the sky 1 1/2 hours after sunset.

Time to catch Comet PANSTARRS … again. While it’s faded to near the naked eye limit, it’s still plainly visible in binoculars, particularly 7×50 or 10×50 models or larger. The comet is probably easier to find than ever because it’s passing through the bright W-shaped constellation Cassiopeia during the next two weeks. Look for it about 90 minutes after sunset in the northwestern sky. PANSTARRS has a brighter head topped by a faint, fan-shaped tail.

Face northeast about 90 minutes before sunrise and find the W of Cassiopeia. Use it to guide you to the comet.

While observers in the northern U.S., Canada and Europe will get equally good views at both dusk and dawn, sky watchers in the southern U.S. will have better luck at dawn when Cassiopeia is higher in the sky. The view through a telescope is still the best with the comet showing  a bright head and nucleus and a classic, gently-curving tail to the north.

Comet PANSTARRS with its amazing tail photographed on April 10 in Austria. Credit: Michael Jaeger

More good news. A strong solar flare erupted in sunspot group 1719 early Thursday morning April 11 sending sprays of solar protons and electrons in Earth’s direction. You know what that means.

The solar flare in sunspot group 1719 photographed in ultraviolet light by NASA’s Solar Dynamics Observatory around 3:30 a.m. CDT April 11. Credit: NASA

Major storm levels and auroras are possible overnight tonight through Sunday the 14th. With little interference from the moon, this could be a good show. I’ll be keeping an eye on the space weather and send out an alert this evening if auroras sprout.