aurora Archives

May 8, 2016May 8, 2016 by Bob King

Give Mom the Aurora Tonight / Mercury Transit Update

A coronal aurora twists overhead in this photo taken early on May 8 from near Duluth, Minn. Credit: Bob King

Skywatchers across the northern tier of states, the Midwest and southern Canada were treated to a spectacular display of the aurora borealis last night. More may be on tap for tonight. Credit: Bob King — Skywatchers across the northern tier of states, the Midwest and southern Canada were treated to a spectacular display of the aurora borealis last night. More may be on tap for tonight — in honor of Mother’s Day of course! Credit: Bob King

Simple choices can sometimes lead to dramatic turns of events in our lives. Before turning in for the night last night, I opened the front door for one last look at the night sky. A brighter-than-normal auroral arc arched over the northern horizon. Although no geomagnetic activity had been forecast, there was something about that arc that hinted of possibility.

It was 11:30 at the time, and it would have been easy to go to bed, but I figured one quick drive north for a better look couldn’t hurt. Ten minutes later the sky exploded. The arc subdivided into individual pillars of light that stretched by degrees until they reached the zenith and beyond. Rhythmic ripples of light – much like the regular beat of waves on a beach — pulsed upward through the display. You can’t see a chill going up your spine, but if you could, this is what it would look like.

Auroras can be caused by huge eruptions of subatomic particles from the Sun’s corona called CMEs or coronal mass ejections, but they can also be sparked by holes in the solar magnetic canopy. Coronal holes show up as blank regions in photos of the Sun taken in far ultraviolet and X-ray light. Bright magnetic loops restrain the constant leakage of electrons and protons from the Sun called the solar wind. But holes allow these particles to fly away into space at high speed. Last night’s aurora traces its origin back to one of these holes.

Visualization of the solar wind encountering Earth's magnetic "defenses" known as the magnetosphere. Clouds of southward-pointing plasma are able to peel back layers of the Sun-facing bubble and stack them into layers on the planet's nightside (center, right). The layers can be squeezed tightly enough to reconnect and deliver solar electrons (yellow sparkles) directly into the upper atmosphere to create the aurora. Credit: JPL — Both a bar magnet (left) and Earth are surrounded by magnetic fields with north and south poles. Earth’s field is shaped by charged particles – electrons and protons – flowing from the sun called the solar wind. Credit: Andy Washnik (left) and NASA

The subatomic particles in the gusty wind come bundled with their own magnetic field with a plus or positive pole and a minus or negative pole. Recall that an ordinary bar magnet also has a “+” and “-” pole, and that like poles repel and opposite poles attract. Earth likewise has magnetic poles which anchor a large bubble of magnetism around the planet called the magnetosphere.

Field lines in the magnetosphere — those invisible lines of magnetic force around every magnet — point toward the north pole. When the field lines in the solar wind also point north, there’s little interaction between the two, almost like two magnets repelling one another. But if the cloud’s lines of magnetic force point south, they can link directly into Earth’s magnetic field like two magnets snapping together. Particles, primarily electrons, stream willy-nilly at high speed down Earth’s magnetic field lines like a zillion firefighters zipping down fire poles. They crash directly into molecules and atoms of oxygen and nitrogen around 60-100 miles overhead, which absorb the energy and then release it moments later in bursts of green and red light.

View of the eastern sky during the peak of this morning's aurora. Credit: Bob King — View of the eastern sky during the peak of this morning’s aurora. Credit: Bob King

So do great forces act on the tiniest of things to produce a vibrant display of northern lights. Last night’s show began at nightfall and lasted into dawn. Good news! The latest forecast calls for another round of aurora tonight from about 7 p.m. to 1 a.m. CDT (0-6 hours UT). Only minor G1 storming (K index =5) is expected, but that was last night’s expectation, too. Like the weather, the aurora can be tricky to pin down. Instead of a G1, we got a G3 or strong storm. No one’s complaining.

So if you’re looking for that perfect last minute Mother’s Day gift, take your mom to a place with a good view of the northern sky and start looking at the end of dusk for activity. Displays often begin with a low, “quiet” arc and amp up from there.

The camera recorded pale purple and red but the primary color visible to the eye was green. Credit: Bob Kin — The camera recorded pale purple, red and green, but the primary color visible to the eye was green. Cameras capture far more color than what the naked eye sees because even faint colors increase in intensity during a time exposure. Details: ISO 800, f/2.8, 13 seconds. Credit: Bob King

Aurora or not, tomorrow features a big event many of us have anticipated for years — the transit of Mercury. You’ll find everything you’ll need to know in this earlier story, but to recap, Mercury will cross directly in front of the Sun during the late morning-early evening for European observers and from around sunrise (or before) through late morning-early afternoon for skywatchers in the Americas. Because the planet is tiny and the Sun deadly bright, you’ll need a small telescope capped with a safe solar filter to watch the event. Remember, never look directly at the Sun at any time.

Nov. 15, 1999 transit of Mercury photographed in UV light by the TRACE satellite. Credit: NASA

If you’re greeted with cloudy skies or live where the transit can’t be seen, be sure to check out astronomer Gianluca Masi’s live stream of the event. He’ll hook you up starting at 11:00 UT (6 a.m. CDT) tomorrow.

The table below includes the times across the major time zones in the continental U.S. for Monday May 9:

Time Zone	Eastern (EDT)	Central (CDT)	Mountain (MDT)	Pacific (PDT)
Transit start	7:12 a.m.	6:12 a.m.	5:12 a.m.	Not visible
Mid-transit	10:57 a.m.	9:57 a.m.	8:57 a.m.	7:57 a.m.
Transit end	2:42 p.m.	1:42 p.m.	12:42 p.m.	11:42 a.m.

December 11, 2015December 23, 2015 by Nancy Atkinson

Watch Fast and Furious All-sky Aurora Filmed in Real Time

Screen shot of video from aurora in Norway from November 2015. Credit: Thierry Legault.

If seeing the Northern or Southern Lights hasn’t been crossed off your bucket list yet, this video is the next best thing to seeing the aurora live. Astrophotographer extraordinaire Thierry Legault has captured spectacular views of the Aurora Borealis from Norway, filmed in real time.

“I was in Norway in early November,” Thierry told Universe Today, “this was my 5th stay and really the best one, with incredible auroras. At moments they were so large and fast that we didn’t know where to look.” He added they were “totally hypnotic.”

The 16-minute video includes 6 of the best sequences Legault captured. “I included the start and finish of the sequences to show their behavior to people who have never witnessed them,” he said. “The auroras seem to be alive, sometimes like snakes or rivers.”

Legault used a Sony Alpha 7s, which he says is the only camera able to record video like this in such lighting. The video is recorded at 25 frames a second.

For the best view of the video, switch to full HD mode (1080p) and full screen.

Legault has been going to Norway annually to see the aurora. Here are the views he captured last year.

See more of Legault’s work at his website. He has technical pages there with advice for capturing the night sky. He provides more details and tips in his excellent book, Astrophotography.

May 13, 2015December 23, 2015 by Bob King

Does the Red Planet Have Green Auroras?

A map of MAVEN's Imaging Ultraviolet Spectrograph (IUVS) auroral detections in December 2014 overlaid on Mars’ surface. The map shows that the aurora was widespread in the northern hemisphere, not tied to any geographic location. The aurora was detected in all observations during a 5-day period. Credits: University of Colorado

Martian auroras will never best the visual splendor of those we see on Earth, but have no doubt. The Red Planet still has what it takes to throw an auroral bash. Witness the latest news from NASA’s MAVEN atmospheric probe.

In December 2014, it detected widespread auroras across Mars’ northern hemisphere dubbed the “Christmas Lights”. If a similar display happened on Earth, northern lights would have been visible from as far south as Florida.

“It really is amazing,” says Nick Schneider who leads MAVEN’s Imaging Ultraviolet Spectrograph (IUVS) instrument team at the University of Colorado. “Auroras on Mars appear to be more wide ranging than we ever imagined.”

A beautiful curtain of rays spread across the northern sky just last night (May 12) as seen from Duluth, Minn. Aurora colors on Earth are caused by the excitation of nitrogen and oxygen atoms from high-speed particles from the solar wind. Oxygen is responsible for most of the aurora's greens and reds. Credit: Bob King — A beautiful curtain of auroral rays spreads across the northern sky last night (May 12) as seen from Duluth, Minn. Aurora colors on Earth are caused by the excitation of nitrogen and oxygen atoms by high-speed particles in the solar wind. Oxygen in particular is responsible for most of the aurora’s greens and reds. Credit: Bob King

Study the map and you’ll see the purple arcs extend to south of 30° north latitude. So what would Martian auroras look like to the human eye? Would we see an arcade of nested arcs if we faced east or west from 30°N? Well, er, yes, if you could see into the ultraviolet end of the spectrum. Mars’ atmosphere is composed mostly of carbon dioxide, so most of the auroral emissions occur when high speed solar wind particles ionize CO2 molecules and carbon monoxide to produce UV light. Perhaps properly suited-up bees, which can see ultraviolet, would be abuzz at the sight.

High-speed particles from the Sun, mostly electrons, strike oxygen and nitrogen atoms in Earth's upper atmosphere. Credit: NASA — High-speed particles from the Sun, mostly electrons, strike oxygen and nitrogen atoms in Earth’s upper atmosphere. As they return to their “relaxed” state, they emit light in characteristic colors. Credit: NASA

That’s not the end of the story however. Martian air does contain 0.13% oxygen, the element that puts the green and red in Earth’s auroras. The “Christmas Lights” penetrated deeply into Mars’ atmosphere, reaching an altitude of just 62 miles (100 km) above its surface. Here, the air is relatively thicker and richer in oxygen than higher up, so maybe, just maybe Christmas came in green wrapping.

Mars has magnetized rocks in its crust that create localized, patchy magnetic fields (left). In the illustration at right, we see how those fields extend into space above the rocks. At their tops, auroras can form. Credit: NASA — Mars has magnetized rocks in its crust that create localized, patchy magnetic fields (left). In the illustration at right, we see how those fields extend into space above the rocks. At their “peaks”, auroras can form. Credit: NASA

Nick Schneider, who leads MAVEN’s Imaging Ultraviolet Spectrograph (IUVS) instrument team, isn’t certain but thinks it’s possible that a diffuse green glow could appear in Mars’ sky during particularly energetic solar storms.

A magnetosphere is that area of space, around a planet, that is controlled by the planet's magnetic field. The shape of the Earth's magnetosphere is the direct result of being blasted by solar wind, compressed on its sunward side and elongated on the night-side, the magnetotail. Credits: NASA — Earth’s magnetosphere, an area of space that’s controlled by the planet’s magnetic field, guides solar wind electrons and protons along magnetic field lines into the atmosphere in the polar regions to create auroras. The planet’s field is created by electric currents generated in its outer nickel-iron core.
Credits: NASA

While the solar wind produces auroras at both Earth and Mars, they originate in radically different ways. At Earth, we’re ensconced in a protective planet-wide magnetic field. Charged particles from the Sun are guided to the Earth’s poles by following a multi-lane freeway of global magnetic field lines. Mars has no such organized, planet-wide field. Instead, there are many locally magnetic regions. Particles arriving from the Sun go where the magnetism takes them.

“The particles seem to precipitate into the atmosphere anywhere they want,” says Schneider. “Magnetic fields in the solar wind drape across Mars, even into the atmosphere, and the charged particles just follow those field lines down into the atmosphere.”

Maybe one day, NASA or one of the other space agencies will send a lander with a camera that can shoot long time exposures at night. We’ll call it the “Go Green” initiative.

March 18, 2015December 23, 2015 by Jason Major

Surprise – Mars Has Auroras Too!

Artist’s conception of MAVEN’s Imaging UltraViolet Spectrograph observing the “Christmas Lights Aurora" on Mars. (University of Colorado)

Just a day after skywatchers at mid- to upper-latitudes around the world were treated to a particularly energetic display of auroras on the night of March 17 as a result of an intense geomagnetic storm, researchers announced findings from NASA’s MAVEN mission of auroral action observed on Mars – although in energetic ultraviolet wavelengths rather than visible light.

Detected by MAVEN’s Imaging Ultraviolet Spectrograph (IUVS) instrument over five days before Dec. 25, 2014, the ultraviolet auroras have been nicknamed Mars’ “Christmas lights.” They were observed across the planet’s mid-northern latitudes and are the result of Mars’ atmosphere interacting directly with the solar wind.

Map of the UV aurora detected on Mars in Dec. 2014 (University of Colorado)

While auroras on Earth typically occur at altitudes of 80 to 300 kilometers (50 to 200 miles) and occasionally even higher, Mars’ atmospheric displays were found to be much lower, indicating higher levels of energy.

“What’s especially surprising about the aurora we saw is how deep in the atmosphere it occurs – much deeper than at Earth or elsewhere on Mars,” said Arnaud Stiepen, IUVS team member at the University of Colorado. “The electrons producing it must be really energetic.”

To a human observer on Mars the light show probably wouldn’t be very dramatic, though. Without abundant amounts of oxygen and nitrogen in its thin atmosphere a Martian aurora would be a dim blue glow at best, if not out of the visible spectrum entirely.

This isn’t the first time auroras have been spotted on Mars; observations with ESA’s Mars Express in 2004 were actually the first detections of the phenomenon on the Red Planet. Made with the spacecraft’s SPICAM ultraviolet spectrometer, the observations showed that Mars’ auroras are unlike those found anywhere else in the Solar System in that they are generated by particle interactions with very localized magnetic field emissions, rather than a globally-generated one (like Earth’s).

(So no, it’s not a total surprise… but it’s still very cool!)

In addition to auroras MAVEN also detected diffuse but widespread dust clouds located surprisingly high in the Martian atmosphere. It’s not yet understood what process is delivering dust so high – 150-300 kilometers up (93-186 miles) – or if it is a permanent or temporary feature.

Source: NASA and Nature

March 18, 2015December 23, 2015 by Nancy Atkinson

Powerful Magnetic Storm Produces Beautiful Aurora Around the World

St Patrick's Day Aurora. This is a 5 image panorama of the Northern Lights display around 10PM in central Maine. Credit and copyright: Mike Taylor/Mike Taylor Photography.

The strong geomagetic storm surprised early risers yesterday on St. Patrick’s Day with a spectacular display of the northern lights, ended up with staying power. According to Spaceweather.com, a fast-moving CME hit Earth’s magnetic field that at first had little effect. But as Earth moved into the CME’s strongly-magnetized wake, the storm intensified until it became a G4-class event. “For more than 9 hours, it was the strongest geomagnetic storm of the current solar cycle,” and the glow of aurora was seen around the world — in the northern hemisphere, anyway — farther south than usual, such as in Kanasa and Virginia in the US and in Oxfordshire, Wiltshire and Hampshire in the UK.

Speaking of ‘around the world,’ astronaut Terry Virts took the Vine video above, from the International Space Station.

Below are more aurora images from Universe Today readers:

Powerful Aurora Borealis from March 18, 2015.Photographed in Saaremaa, Estonia. Credit and copyright: Marko Palm.

Aurora on St. Patrick's Day night, seen west of Keene, Ontario, Canada at about 10:00 p.m. EDST. Credit and copyright: Rick Stankiewicz — Aurora on St. Patrick’s Day night, seen west of Keene, Ontario, Canada at about 10:00 p.m. EDST. Credit and copyright: Rick Stankiewicz

Aurora borealis as seen from Leek in Staffordshire, England on March 17, 2015. Credit and copyright: Gareth Harding.

90 Minute Aurora Star Trails as seen from the UK on March 17, 2015. Credit and copyright: Mary Spicer.

The team from the Slooh telescope had a special broadcast last night from Iceland to showcase the aurora, and the skies were alive with brilliant, green aurora. Here is a highlight, showcasing some of the incredible moments:

March 17, 2015December 23, 2015 by Bob King

Green and Red Auroras Light Up St. Patrick’s Day Dawn

Just in time for St. Patrick's Day - a — A spectacular green and red aurora photographed early this morning March 17, 2015, from Donnelly Creek, Alaska. Credit: Sebastian Saarloos

A strong G3 geomagetic storm surged across the planet this morning producing a spectacular display of the northern lights. Some of you may who may have risen to see the new nova were no doubt as surprised as the NOAA space weather folks, whose overnight forecast did not include an alert for even a minor storm.

So what happened? Let’s just say the Sun isn’t always as predictable as we’d like. An interplanetary shock wave in the form of a sudden increase in the solar wind speed from 250 miles per second to 375 mph (400-600 km/sec) began blasting Earth shortly before midnight. It appears the combined effects of earlier coronal mass ejections (CMEs) and an outpouring of high-speed solar particles from a gaping hole in the Sun’s magnetic canopy crashed through Earth’s magnetic defenses.

Particle-wise, all hell broke loose. You can start looking for more as soon as it gets dark tonight.

A powerful X2.2-class flare from sunspot region 2297 glows fiery yellow in this photo taken by NASA’s Solar Dynamics Observatory on March 11, 2015. Credit: NASA — A powerful X2.2-class flare from sunspot region 2297 glows intensely in this photo taken in short wavelength ultraviolet light by NASA’s Solar Dynamics Observatory on March 11, 2015. Credit: NASA Goddard SDO

We know that recent flares from sunspot group 2297 have sent more than a few billows of solar particles our way called CMEs or coronal mass ejections. Weekend forecasts called for minor storms but little materialized. Only when we thought it was safe to go back to bed did the aurora pounce. Reading the magnetospheric tea leaves, better known as the Kp index, a measure of magnetic activity high overhead in Earth’s ionosphere, quiet conditions gave way to auroral abandon starting around 1 a.m (CDT) today.

A wall of colorful red and green aurora met the eye and camera of Jim Schaff of Duluth this morning around 3 a.m. CDT. Credit: Jim Schaff

Like a spring grassfire the northern lights took off from there and burned till dawn, peaking between 2 and 4 a.m. Most of us are usually asleep during those deep hours of the night, but I’m hoping those who arose to see the nova or catch the lunar crescent at dawn may have been as surprised and delighted as I was to see auroras.

Like paw prints made by a cat, pale green auroral rays mark the northern sky around 5:45 a.m this morning March 17. Credit: Bob King

More are in the offing. The latest space weather forecast calls for continued severe storms (G3 or higher) to continue through tonight. G1 or minor storms are normally only visible as arcs or low rays across the north from the northern tier of states, but if tonight’s forecast holds, a fair portion of the U.S. should see auroras. Keep an eye peeled for bright, moving glow and arcs across the northern sky.

The awesome 30-minute aurora forecast map updates the shrinking and expanding of Earth's northern auroral oval due to changes in the solar wind from CMEs, flares and the like. This view is from this morning around 4:55 a.m. Red indicates intense aurora. Credit: NOAA — The awesome 30-minute aurora forecast map updates the shrinking and expanding of Earth’s northern auroral oval due to changes in the solar wind from CMEs, flares and the like. This view is from this morning around 4:55 a.m. Red indicates intense aurora. Credit: NOAA

There are lots of tools available you can use yourself to know if auroras are lurking about. First, check the NOAA 3-day space weather forecast. There you’ll see a list of times along with a Kp index number indicating magnetic activity. Number “1-4” means no storm and little likelihood you’ll see an aurora. “5” indicates a minor storm; the higher the number the more severe the storm and more widespread the northern lights will be.

Curtains of aurora still pushed through the growing light of dawn. Credit: Bob King — Curtains of aurora still pushed through the growing light of dawn (blue sky at top). Credit: Bob King

There’s also a nice visual representation of the numbers on the Planetary K-index site, where magnetic activity is updated every 3 hours. The dashed line on the bar chart represents 0 UT or 7 p.m. CDT. One of my favorites and the ultimate visual feast of an aurora indicator is NOAA’s Aurora 30-minute Forecast. Here you get a birds-eye representation of the current aurora based on satellite data. When the permanent auroral oval expands southward and intensifies, put on your coat and head out for a look. For education and entertainment, click on the gray arrow below the graphic and you’ll see a whole day’s worth of activity play out before your eyes. Totes cool.

ACE plot from a June 2013 aurora. Note the steep drop in the Bz. Credit: NOAA — ACE plot from a June 2013 aurora. Note the steep drop in the Bz. ACE orbits around the L1 Lagrange point about a million miles ahead of Earth in the direction of the Sun. There it studies the incoming particle streams from the Sun hours before they reach Earth. Credit: NOAA

I’m also in big believer in the the Advanced Composition Explorer (ACE) Bz plot. Bz is the direction of the embedded solar magnetic field that gift-wraps the streams of high-speed particles sent our way by the Sun. Like a magnet, it has a south pole and a north pole. When the south pole of the field sweeps by – what scientists call a negative Bz – the blast is more likely to link up with Earth’s magnetic field and spark auroras. When you see the Bz “head south” to -5 or lower, there’s a chance for auroras.

Now that you’re armed with information, cross your fingers all the indicators will point in the right direction for the aurora to continue tonight. And yes, Happy St. Patrick’s Day!

Skiing stop to take in the northern lights near Fairbanks Monday night. Credit: John Chumack — Skywatchers stop to take in the northern lights near Fairbanks Monday night. Credit: John Chumack

UPDATE: The storm continues and is now rated G4 or severe as of 10 a.m. CDT. Lucky for you if you live somewhere where it’s dark right now.

March 4, 2015December 30, 2015 by Jason Major

Watch the Aurora Shimmer and Dance in Real Time

I for one have never witnessed the northern lights in person, and like many people I experience them vicariously through the photography and videos of more well-traveled (or more polar-bound) individuals. Typically these are either single-shot photos or time-lapses made up of many somewhat long-exposure images. As beautiful as these are, they don’t accurately capture the true motion of this upper atmospheric phenomenon. But here we get a look at the aurora as it looks in real time, captured on camera by Jon Kerr from northern Finland. Check it out above or watch in full screen HD on YouTube.

The video was shot with a full-frame mirrorless Sony a7S. See more of Jon’s aurora videos on YouTube here.

Video credit: Jon Kerr. HT SunViewer on Twitter.

December 29, 2014December 23, 2015 by Nancy Atkinson

Stunning Aurora Timelapse from Iceland, December 2014

Aurora dancing in the Hvalfjörður fjord in Iceland. Credit and copyright: Ólafur Haraldsson.

As we get ready to wrap up the year and the month, here’s an absolutely beautiful compilation of views of the aurora — or norðurljós as they are called in Icelandic — from the month of December 2014 in Iceland.

“Even though the month is not over yet, the weather forecast does not allow any shooting the rest of the month,” said photographer Ólafur Haraldsson via email.

Haraldsson’s timelapse captures the quiet and magical beauty of the aurora and the majestic and varied landscapes of Iceland.

See more of Haraldsson’s wonderful work on his website — which includes some amazing 360 degree interactive panoramas — or on Twitter and Instagram.

Aurora December 2014 from Olafur Haraldsson on Vimeo.

December 27, 2014December 23, 2015 by Bob King

Comet Q2 Lovejoy Loses Tail, Grows Another, Loses That One Too!

Panel of negative images showing the tail of Comet Lovejoy disconnecting. Credit: Hisayoshi Kato

Maybe you’ve seen Comet Q2 Lovejoy. It’s a big fuzzy ball in binoculars low in the southern sky in the little constellation Lepus the Hare. That’s the comet’s coma or temporary atmosphere of dust and gas that forms when ice vaporizes in sunlight from the nucleus. Until recently a faint 3° ion or gas tail trailed in the coma’s wake, but on and around December 23rd it snapped off and was ferried away by the solar wind. Just as quickly, Lovejoy re-grew a new ion tail but can’t seem to hold onto that one either. Like a feather in the wind, it’s in the process of being whisked away today.

Magnetic field lines bound up in the sun’s wind pile up and drape around a comet’s nucleus to shape the blue ion tail. Notice the oppositely-directed fields on the comet’s backside. The top set points away from the comet; the bottom set toward. In strong wind gusts, the two can be squeezed together and reconnect, releasing energy that snaps off a comet’s tail. Credit: Tufts University.

Easy come, easy go. Comets usually have two tails, one of dust particles that reflect sunlight and another of ionized gases that fluoresce in Sun’s ultraviolet radiation. Ion tails form when cometary gases, primarily carbon monoxide, are ionized by solar radiation and lose an electron to become positively charged. Once “electrified”, they’re susceptible to magnetic fields embedded in the high-speed stream of charged particles flowing from the Sun called the solar wind. Magnetic field lines embedded in the wind drape around the comet and draw the ions into a long, skinny tail directly opposite the Sun.

Part of Comet Lovejoy Q2's ion tail (left) cuts the cord and floats away from the comet as photographed on December 23, 2014. Credit: Chris Schur — Part of Comet Lovejoy Q2’s ion tail (left) cuts the cord and floats away from the comet as photographed on December 23, 2014. Carbon monoxide in the tail fluoresces blue in ultraviolet sunlight. Credit: Chris Schur

Disconnection events happen when fluctuations in the solar wind cause oppositely directed magnetic fields to reconnect in explosive fashion and release energy that severs the tail. Set free, it drifts away from the comet and dissipates. In active comets, the nucleus continues to produce gases, which in turn are ionized by the Sun and drawn out into a replacement appendage. In one of those delightful coincidences, comets and geckos both share the ability to re-grow a lost tail.

Comet Encke tail disconnection April 20, 2007 as seen by STEREO

Comet Halley experienced two ion tail disconnection events in 1986, but one of the most dramatic was recorded by NASA’s STEREO spacecraft on April 20, 2007. A powerful coronal mass ejection (CME) blew by comet 2P/Encke that spring day wreaking havoc with its tail. Magnetic field lines from the plasma blast reconnected with opposite polarity magnetic fields draped around the comet much like when the north and south poles of two magnets snap together. The result? A burst of energy that sent the tail flying.

Diagram showing how a CME slams into a comet (B) to create a tail disconnection event, known in the biz as a DE. Soon enough the comet grows a new one (D). Credit: NASA — Diagram showing how a CME slammed into Comet Encke (B) and snapped off its tail. Soon enough, the comet grew a new one (D). Credit: NASA

Comet Lovejoy may have also crossed a sector boundary where the magnetic field carried across the Solar System by Sun’s constant breeze changed direction from south to north or north to south, opposite the magnetic domain the comet was immersed in before the crossing. Whether solar wind flutters, coronal mass ejections or sector boundary crossings, more tail budding likely lies in Lovejoy’s future. Like the chard in your garden that continues to sprout after repeated snipping, the comet seems poised to spring new tails on demand.

Because Comet Lovejoy rapidly moves into the evening sky by mid-late December, its position on this detailed map is shown at 10 p.m. (CST) nightly. Credit: — Comet Lovejoy picks up speed in late December as it travels from southern Lepus into Eridanus. Its position shown nightly at 10 p.m. (CST). On Sunday night December 28th it passes very close to the bright globular cluster M79. Stars shown to magnitude +8.0. Source: Chris Marriott’s SkyMap software

If you haven’t seen the comet, it’s now glowing at magnitude +5.5 and faintly visible to the naked eye from a dark sky site. Without an obvious dust tail and sporting a faint ion tail(s), the comet’s basically a giant coma, a fuzzy glowing ball easily visible in a pair of binoculars or small telescope.

A second tail disconnection event recorded on December 26, 2014 by John Nassr from his observatory in Baguio, Philippines. The fram is 3 wide. Credit: John Nassr — A second tail disconnection event recorded on December 26, 2014 by John Nassr from his observatory in Baguio, Philippines. The frame is 3° wide. Credit: John Nassr

In a very real sense, Comet Lovejoy experienced a space weather event much like what happens when a CME compresses Earth’s magnetic field causing field lines of opposite polarity to reconnect on the back or nightside of the planet. The energy released sends millions of electrons and protons cascading down into our upper atmosphere where they stimulate molecules of oxygen and nitrogen to glow and produce the aurora. One wonders whether comets might even experience their own brief auroral displays.

Excellent visualization showing how magnetic fields line on Earth’s nightside reconnect to create the rain of electrons that cause the aurora borealis. Notice the similarity to comet tail loss.

December 26, 2014December 23, 2015 by Ken Kremer

Spectacular Earth Timelapse Video: Christmas Gift from Alexander Gerst’s 2014 ISS Voyage

Another new snapshot of Earth’s “beautiful Southern Lights” taken from the ISS on 5 July 2014. Credit: ESA/Alexander Gerst

Video Caption: Watch the Earth roll by through the perspective of German astronaut Alexander Gerst in this 4K six-minute timelapse video of images taken from on board the International Space Station (ISS) during 2014. Credit: Alexander Gerst/ESA

ESA astronaut Alexander Gerst from Germany who recently returned from a six month voyage to the International Space Station (ISS) has a special Christmas gift for all – a stunning six-minute timelapse compilation of his favorite images of Earth taken during his “Blue Dot” mission in 2014.

“A 4K timelapse showing our planet in motion, from my favourite Earth images taken during the Blue Dot mission,” wrote Gerst in connection with his spectacular timelapse video released to coincide with Christmastime.

“I wish all of you a merry Christmas! It was a wild year for me, thanks for joining me on this fascinating journey!” said Gerst in English.

“Wünsche euch allen fröhliche Weihnachten! War ein wildes Jahr für mich, vielen Dank, dass ihr mit dabei wart!” said Gerst in German.

You can watch the Earth roll by through Gerst’s perspective in this six-minute timelapse video combining over 12,500 images taken during his six-month mission aboard the ISS that shows the best our beautiful planet has to offer.

“Marvel at the auroras, sunrises, clouds, stars, oceans, the Milky Way, the International Space Station, lightning, cities at night, spacecraft and the thin band of atmosphere that protects us from space,” according to the video’s description.

Gerst would often would set cameras to automatically take pictures at regular intervals while doing his science research or preparing for the docking of other spacecraft at the ISS in order to get the timelapse effect shown in the video.

“Scary. The sunlight is far from reaching down the abyss of Neoguri's 65 km-wide eye.” Taken from the ISS on 8 July 2014. Credit: ESA/NASA/Alexander Gerst — “Scary. The sunlight is far from reaching down the abyss of Neoguri’s 65 km-wide eye.” Taken from the ISS on 8 July 2014. Credit: ESA/NASA/Alexander Gerst

The robotic arm capture and berthing of the SpaceX Dragon cargo ship and the release of the Orbital Sciences Cygnus cargo freighter are particularly magnificent in a rarely seen timelapse glimpse of visiting vehicles that are absolutely essential to keeping the station afloat, stocked, and humming with research activities.

Gerst served aboard the ISS between May and November this year as a member of the Expedition 40 and 41 crews.

Gerst launched to the ISS on his rookie space flight on May 28, 2014, aboard the Russian Soyuz TMA-13M capsule along with Russian cosmonaut Maxim Suraev and NASA astronaut Reid Wiseman.

They joined the three station flyers already aboard – cosmonauts Alexander Skvortsov & Oleg Artemyev, and astronaut Steve Swanson – to restore the station crew complement to six.

Gerst and Wiseman became well known and regarded for their prolific and expertly crafted photography skills.

ESA astronaut Alexander Gerst, Russian commander Maxim Suraev and NASA astronaut Reid Wiseman returned to Earth on 10 November 2014, landing in the Kazakh steppe. Credit: ESA–S. Corvaja — ESA astronaut Alexander Gerst, Russian commander Maxim Suraev, and NASA astronaut Reid Wiseman returned to Earth on 10 November 2014, landing in the Kazakh steppe. Credit: ESA–S. Corvaja

They returned to Earth safely on Nov. 10, 2014, with a soft landing on the Kazakh steppes.

Alex is Germany’s third astronaut to visit the ISS. He conducted a spacewalk with Wiseman on Oct. 7 while aboard. He is trained as a geophysicist and a volcanologist.

ESA astronaut Alexander Gerst spent six hours and 13 minutes outside the International Space Station with NASA astronaut Reid Wiseman on Tuesday, 7 October 2014. This was the first spacewalk for both astronauts but they performed well in the weightlessness of orbit. Credit: NASA/ESA

Read my story detailing Christmas 2014 festivities with the new crews at the ISS – here.

Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.

Ken Kremer