The Northern Lights (Part Two)

Northern Lights at a latitude of about 70 degrees north, well within the Arctic Circle. These photos were taken about 30 miles from the town of Alta. (Lisa Braithwaite)

In my recent column about The Northern Lights, the Magnetic Field and Life,  I explored the science and the beauty of our planet’s aurora borealis, one of the great natural phenomenon we are most fortunate to see in the far North (and much less frequently in the not-quite-so-far North.)

I learned the hard way that an IPhone camera was really not up to the job;  indeed, the battery froze soon after leaving my pocket in the 10 degrees F cold.  So the column had few images from where I actually was — about a half hour outside of the Arctic Circle town of Alta.

But here now are some images taken by a generous visitor to the same faraway lodge, who was present the same time as myself.

Her name is Lisa Braithwaite and she is an avid amateur photographer and marketing manager for two popular sites in the English Lake District.  This was her first hunting trip for the Northern Lights, and she got lucky.  Even in the far northern Norway winter the lights come and go unpredictably — though you can increase your chances if you show up during a time when the sun is actively sending out solar flares.

She came with a Panasonic Lumix DMC-G5 camera and did a lot of research beforehand to increase her chances of capturing the drama should the lights appear.  Her ISOs ranged from 1,600 to 64,000, and her shutter speed from 5 to 15 seconds.  The aperture setting was 3.5.

In addition to showing some of her work, further on I describe a new NASA-led and international program, based in Norway, to study the still incompletely understood dynamics of what happens when very high energy particles from solar flares meet Earth’s atmosphere.

Partnering with the Japanese Aerospace Exploration Agency (JAXA,) the University of Oslo an other American universities, the two year project will send eleven rockets filled with instruments into the ionosphere to study phenomenon such as the auroral winds and the turbulence that can cause so much trouble to communications networks.

But first, here are some morre of Braithwaite’s images, most taken over a one hour period on a single night.

Arcs are a common feature of the lights, sometimes reaching across the sky. They form and then break up into smaller patches. (Lisa Braithwaite.)


The line of the Arctic Circle line can be seen a little more than half-way up the map. The Circle is the most northerly of the five major circles of latitude as shown on maps of Earth. At about 65 degrees North, it marks the northernmost point at which the noon sun is just visible on the December solstice and the southernmost point at which the midnight sun is just visible on the June solstice. (

Vast curtains of light are a common feature, often on the horizon but on good nights high up into the sky.  The lights can sometimes shimmer and dance, and can feature what appear to be vast spotlights.


The lights are often green — the result of interactions between high energy solar flares and oxygen.  If the lights are blue, then nitrogen is in play.  (Lisa Braithwaite)


At certain points in the night, large parts of the sky were lit up — leaving us turning and craning our heads to see what might be happening in different regions. (Lisa Braithwaite)


The light shows often start and end with green horizons.  (Lisa Braithwaite)

While the grandeur of the lights attracts an ever increasing number of adventurous lovers of natural beauty, NASA is also busy in Norway studying the forces that cause the Aurora Borealis — both for the pure science and to better understand the “space weather” that can effect astronauts in low Earth orbit as well as GPS and other communication signals.

The agency has partnered with Norwegian and Japanese colleagues, and other American scientists, in an effort to generally better understand the Earth’s polar cusp — where the planet’s magnetic field lines bend down into the atmosphere and allow particles from space to intermingle with those of Earthly origin.

Solar flares consist of electrically charged particles. They are attracted by the concentrated magnetic fields in the ionosphere around the Earth’s polar regions. This is the reason why the glorious light shows can be observed pretty much exclusively in the far north or the far south.

The two-year project will send eight rockets into space from Norway as part of collaboration of scientists known as The Grand Challenge Initiative – Cusp.

The first mission, the Auroral Zone Upwelling Rocket Experiment or AZURE, is scheduled to launch this month.  The rocket will take off from Norway’s Andøya Space Center, on an island off the far northwest coast of Norway, about 100 miles southwest of where I was near the town of Alta.

As a NASA release of March 1 described it, AZURE’s instruments will measure the atmospheric density and temperature of the polar atmosphere, and will deploy visible tracers — trimethyl aluminum (TMA) and a barium/strontium mixture, which ionize when exposed to sunlight.

Personnel from NASA’s Wallops Flight Facility in Virginia conduct payload tests for the AZURE mission at the Andøya Space Center in Norway. (NASA’s Wallops Flight Facility)

“These mixtures create colorful clouds that allow researchers to track the flow of neutral and charged particles, respectively,” the release reads. “The tracers will be released at altitudes 71 to 155 miles high and pose no hazard to residents in the region.

“By tracking the movement of these colorful clouds via ground-based photography and triangulating their moment-by-moment position in three dimensions, AZURE will provide valuable data on the vertical and horizontal flow of particles in two key regions of the ionosphere over a range of different altitudes.

“Such measurements are critical if we are to truly understand the effects of the mysterious yet beautiful aurora. The results will be key to a better understanding of the effects of auroral forcing on the atmosphere, including how and where the auroral energy is deposited.”

AZURE will focus specifically on measuring the vertical winds in these polar regions, which create a tumultuous particle soup that re-distributes the energy, momentum and chemical constituents of the atmosphere.

AZURE will study the ionosphere, the electrically charged layer of the atmosphere that acts as Earth’s interface to space, focusing specifically on the E and F regions. The E region — so-named by early radio pioneers who discovered that the region was electrically charge, and so could reflect radio waves — lies between 56 to 93 miles above Earth’s surface. The F region resides just above it, between 93 to 310 miles altitude.

The E and F regions contain free electrons that have been ejected from their atoms by the energizing input of the Sun’s rays, a process called photoionization. After nightfall, without the energizing input of the Sun to keep them separated, electrons recombine with the positively charged ions they left behind, lowering the regions’ overall electron density. The daily cycle of ionization and recombination makes the E and F regions especially turbulent and complex.

Aurora as seen from Talkeetna, Alaska, on Nov. 3, 2015. (Copyright Dora Miller)

It has been known for a century that solar flares create the fantastic displays of the Northern and Southern lights.  More recently, it has also become well known that solar flares cause problems for both satellites and navigation systems.

Despite decades of study, scientists still lack the basic knowledge required for predicting when such problems will occur. Once they understand this, it should be possible to make good space weather forecasts just like we do with our weather forecasts on Earth.

When solar storms rain down on the Earth, they cause turbulence in the ionosphere.  This turbulence is one of the major unsolved problems of classical physics and physicists are hoping that the rockets will lead to a far better understanding of the phenomenon.

“Without such an understanding of turbulence it is impossible to make the calculations needed for being able to predict severe space weather events,” said Joran Moen of the University of Oslo, and one of the project leaders. He spoke with the University of Oslo research magazine “Apollon.”

The rockets of The Grand Challenge Initiative – Cusp  mission will launch over the next two years from the Andøya and Svalbard rocket ranges in Norway. Nine of the rockets are from NASA, one from JAXA and one building built the at the University of Norway.

One particular “sounding” will be made with the launch of four rockets at once, an unusual and complex procedure.

Those involved say this will be among the most ambitious attempts ever using rockets for research purposes.

“We will try to launch four of the rockets at the same time. This has never been done before. It is a historic venture,” said Moen.

Yoshifumi Saito of JAXA further explained that “the four parallel rockets are important for us.  By using them we can obtain much better scientific results than would have been the case if we had just launched one rocket at a time.”

Important and compelling science.  And think of how many times the scientists will be able to experience the glories of the Northern Lights show.



The Northern Lights, the Magnetic Field and Life

Northern Lights over a frozen lake in Northern Norway, inside the Arctic Circle near Alta. The displays can go on for hours, or can disappear for days or weeks. It all depends on solar flares. (

May I please invite you to join me in the presence of one of the great natural phenomena and spectacles of our world.

Not only is it enthralling to witness and scientifically crucial, but it’s quite emotionally moving as well.

Why? Because what’s before me is a physical manifestation of one of the primary, but generally invisible, features of Earth that make life possible. It’s mostly seen in the far northern and far southern climes, but the force is everywhere and it protects our atmosphere and us from the parched fate of a planet like Mars.

I’m speaking, of course, of the northern lights, the Aurora Borealis, and the planet’s magnetic fields that help turn on the lights.

My vantage point is the far northern tip of Norway, inside the Arctic Circle. It’s stingingly cold in the silent woods, frozen still for the long, dark winter, and it’s always an unpredictable gift when the lights show up.

But they‘re out tonight, dancing in bright green and sometimes gold-tinged arches and spotlights and twirling pinwheels across the northerly sky. Sometimes the horizon glows green, sometimes the whole sky fills with vivid green streaks.

It can all seem quite other-worldly. But the lights, of course, are entirely the result of natural forces.


Northern Lights over north western Norway. Most of the lights are green from collisions with oxygen, but some are purple from nitrogen. © Copyright George Karbus Photography

It has been known for some time that the lights are caused by reactions between the high-energy particles of solar flares colliding in the upper regions of our atmosphere and then descending along the lines of the planet’s magnetic fields. Green lights tell of oxygen being struck at a certain altitude, red or blue of nitrogen.

But the patterns — sometimes broad, sometimes spectral, sometimes curled and sometimes columnar — are the result of the magnetic field that surrounds the planet. The energy travels along the many lines of that field, and lights them up to make our magnetic blanket visible.

Such a protective magnetic field is viewed as essential for life on a planet, be it in our solar system or beyond.

But a magnetic field does not a habitable planet make. Mercury has a weak magnetic field and is certainly not habitable. Mars also once had a strong magnetic field and still has some remnants on its surface. But it fell apart early in the planet’s life, and that may well have put a halt to the emergence or evolution of living things on the otherwise habitable planet.

I will return to some of the features of the northern lights and the magnetism is makes visible, but this is also an opportunity to explore the role of magnetism in biology itself.

This was a quasi-science for some time, but more recently it has been established that migrating birds and fish use magnetic sensors (in their beaks or noses, perhaps) to navigate northerly and southward paths.

Graphic from Science Magazine.


But did you know that bacteria, insects and mammals of all sorts appear to have magnetic compasses as well?   They can read the magnetism in the air, or can read it in the rocks (as in the case of some sea turtles.) A promising line of study, pioneered by scientists including geobiologist Joseph Kirschvink of the California Institute of Technology (Caltech) and the Earth-Life Science Institute (ELSI) in Tokyo, is even studying potentially remnant magnetic senses in humans.

“There no doubt now that magnetic receptors are present in many, many species, and those that don’t have it probably lost it because it wasn’t useful to them,” he told me. “But there’s good reason to say that the magnetic sense was most likely one of the earliest on Earth.”

But how does it work for animals? How do they receive the magnetic signals? This is a question of substantial study and debate.

One theory states that creatures use the iron mineral magnetite — that they can produce and consume – to pick up the magnetic signals. These miniature compass needles sit within receptor cells, either near a creature’s nose or in the inner ear.

Joseph Kirschvink, a geobiologist with Caltech and ELSI (the Earth-Life Science Institute in Tokyo) has been studying for decades the ways in which creatures from bacteria to humans use magnetic forces in their lives. (Caltech)

Another posits that magnetic fields trigger quantum chemical reactions in proteins called cryptochromes, which have been found in the retina. But no one has determined how they might send signals and information to the brain.

Kirschvink was part of a team that demonstrated bacteria’s use of Earth’s magnetic field back to the Archean era, 3 to 3.5 billion years ago.   “My guess is that magnetism has had a major influence on the biosphere since then, via the biological ability to make magnetic materials.”

He said that when the sun is particularly angry and active, the geomagnetic storms that occur around the planet seem to interfere with these magnetic responses and that animals don’t navigate as well.

Kirschvink sees magnetism as a possibly important force in the origin of life. Magnetite that is lined up like beads on a chain has been detected in bacteria, and he says it may have provided an evolutionary pathway for structure that allowed for the rise of eukaryotes — organisms with complex cells, or a single cell with a complex structures.

Kirschvink and his team are in the midst of a significant study of the effects of geomagnetism on humans, and the pathways through which that magnetism might be used.

That’s rather a long way from some of the early biomagnetism discoveries, which involved the chiton.  A mollusk relative of the snail and the limpet, the chiton holds on to rocks in the shallow water and uses its magnetite-covered teeth to scrape algae from rocks.  The teeth are on a tongue-like feature called the radula and those teeth are capped with so much magnetite that a magnet can pick up the foot-long gumboot chiton, the largest of the species.

The underside of a gumboot chiton, with its teeth covered with magnetite, can be lifted up with a magnet.

Back at most northern and southerly regions of the planet, where the magnetic field lines are most concentrated, the lights put on their displays for ever larger audiences of people who want to experience their presence.

We had part of one night of almost full sky action, with long arches, curves large and small, waves, spotlights , shimmers and curtains.  It had the feel of a spectacular fireworks display, but magnified in its glory and power and, of course, entirely natural.  (I hope to post images taken by others that night which, alas, were not captured by my camera because the battery froze in the 10 degree cold.)

Our grand night was one of the special ones when the colors (almost all greens, but some reds too) were so bright that their shapes and movements were easy to see with the naked eye.

Good cameras (especially those with batteries that don’t freeze) see and capture a much broader range of the northern light presence.  The horizon, for instance, can appear just slightly green to the naked eye, but will look quite brightly green in an image.

Thanks to the National Oceanic and Atmospheric Administration, the National Weather Service and NASA, forecasting when and where the lights are likely to be be active in the northern and southern (the Aurora Australis) polar regions.

This forecasting of space weather revolves around the the eruption of solar flares.  The high-energy particles they send out collide with electrons in our upper atmosphere accelerate and follow the Earth’s magnetic fields down to the polar regions.

Models based on measuring solar flares, or coronal mass ejections, coming from sunspots that rotate and face Earth every 27 or 28 days.  Summer months in the northern hemisphere often make the sky too light for the lights to be seen, so the long winter nights are generally the best time to see them.  But they do appear in summer, too.  (NOAA)

In these collisions, the energy of the electrons is transferred to the oxygen and nitrogen and other elements in the atmosphere, in the process exciting the atoms and molecules to higher energy states. When they relax back down to lower energy states, they release their energy in the form of light. This is similar to how a neon light works.

The aurora typically forms 60 to 400 miles above Earth’s surface.

All this is possible because of our magnetic field, which scientists theorize was created and is sustained by interactions between super-hot liquid iron in the outer core of the Earth’s center and the rotation of the planet.  The flowing or convection of liquid metal generates electric currents and the rotation of Earth causes these electric currents to form a magnetic field which extends around the planet.

If the magnetic field wasn’t present those highly charged particles coming from the sun, the ones that set into motion the processes that produce the Northern and Southern Lights, would instead gradually strip the atmosphere of the molecules needed for life.

This intimate relationship between the magnetic field and life led to me ask Kirschvink, who has been studying that connection for decades, if he had seen the northern or southern lights.

No, he said, he’d never had the chance.  But if ever in the presence of the lights, he said he know exactly what he would do:  take out his equipment and start taking measurements and pushing his science forward.

Northern Lights in northern Norway, near Alta.  Sometimes they dance for minutes, sometimes for hours, but often they never come at all.  It all depends on the rotation of the sun; if and when it may be shooting out high-energy solar flares. (Wiki Commons)