Andøya Space Center, Andenes, Norway
January 22, 2018

In January of 2018, I traveled to Andøya Space Center in Andenes, Norway, to attend a four day rocket field school. My name is Hannah Gulick, and I am a sophomore at the University of Iowa studying astronomy, physics, and creative writing. I went as one of two University of Iowa students to be part of a rocket campaign in which we designed, built, flew, and analyzed data from a sounding rocket. We were the first American students to join 17 other Canadian and Norwegian students at the space center for the CaNoRock program. Andenes, being about 300 kilometers (190 miles) north of the Arctic Circle, is a stunning landscape of mountains, fjords, and the ocean, and promises days without sun in the winter and nights without darkness in the summer. It is also frequented by the aurora. Aurora, while incredible to watch, also offer a lot of scientific achievement. The scientists at Andøya Space Center (ACS) take full advantage of this research possibility, by launching sounding rockets into the aurora to learn things about magnetic fields and their corresponding properties, like movement. This research helps space physicists to being an understanding of space weather, and find ways to protect Earth from its hostile moments. The reason for all of this research also means that Andøya Space Center is a promising place to see the aurora, with a near fifty-fifty chance it will appear each night.
Knowing this, my University of Iowa team and I endured the two-and-a-half-day, five-plane journey it took to get to Andenes, and hoped for a night that was cloudless and full of the northern lights.

This night came not once, but twice, during our four day stay at ACS. The first time was our second night in Andenes, and it was a surreal experience. The aurora started early in the evening, around seven pm (they normally start around ten-eleven pm), with a dim green line peeking from behind a wall of mountains. Most of the students at CaNoRock, myself included, had never seen the aurora before, so we put on reflective jackets and walked down the road, away from the light pollution given by the space center. It did not take long before the aurora took over the sky in shining green waves that poured from between mountain peaks and out across the ocean. It was a scene many of the scientists at ASC had seen before, and even tested with a sounding rocket, but a scene that, nonetheless, demanded everyone’s attention and left them with a feeling of awe and an inability to fully appreciate the night sky.

The next day, the CaNoRock students felt the same motivation and curiosity instilled in the professionals working at ACS by the watching the aurora, as productivity was at an all time high. There were five CaNoRock teams; payload, rocket telemetry, rocket physics, TM readout, and rocket systems. Each team worked to complete an important piece of the rocket campaign, from building instruments, and designing software that could read data sent back from the rocket, to controlling radio antennas during the rocket’s launch, and calculating where the rocket would land.

I worked as part of the rocket physics team to calculate the flight mechanics of the sounding rocket during launch. Our rocket was a Mongoose 98 with a carbon fiber body tube and aluminum nose cone, measuring in at eight feet eight inches tall. I worked with my team to apply a simulation with the actual size and shape of the Mongoose to find the temperature, pressure, and air density around the rocket’s body as it would be when beginning its ascent into the sky. We found that even the slightest inconsistency in its exterior, a parasitic point or divot a millimeter deep, would drastically affect the way the rocket would take off and continue through flight. This is very important, as the Mongoose is launched toward the ocean, but as our simulation showed, even a millimeter can make a difference, and a difference can be dangerous with a space center, fishing boats, and a town nearby. We then applied this when testing the rocket’s spin and flight trajectory as altered by a change in a parameter like fin shape.

When launch time finally came around, inspired by the northern lights, we prepared our launch as if we were testing the aurora (which we weren’t, it was daytime and we would have needed a much bigger rocket). I was elected principal investigator of the campaign, and I was able to lead the science report relayed over the intercom to all of the different rocket systems. The report consisted of interpreting space weather conditions and magnetic field directions for a real aurora sounding rocket. This meant that we were learning how to check whether the solar wind lines were pointing to the north or south, and finding the magnitude of the vertical magnetic field lines as we were preparing for the launch. As the countdown finished, and our rocket began to take flight, we all watched, proud of our week’s work. The celebration was brief, however, as we immediately began analyzing our successful data, predicting altitude, finding drag coefficients, and calculating speed and acceleration. Our rocket, we concluded, reached an altitude of approximately 8.4 kilometers, the highest one yet.

At CaNoRock, I found a new understanding of mathematical applications, simulation use, and an awareness that there is more to rocket science than just building a rocket. Interpreting raw data, that is not presented like a question in a physics textbook or with a known solution, is difficult and uncertain. We had to decide how to read our data, whether instances in our results were real anomalies or radio dropouts, and if our instrumentation was even working correctly. However, with time and collaboration, we finished our week with answers; about our rocket launch and our careers. We left Andøya having begun our journey from students to early career astrophysicists and engineers, waiting for our chance to watch a rocket fly into the night time aurora.

Thanks to Hannah, Profs. Alison Jaynes and David Miles at U. Iowa for this guest post!

I left Maryland early in the morning to arrive in Calgary early in the afternoon. I had just enough time to change into my aurora dress and catch a meetup of the Alberta Aurora Chasers, fortuitously timed for my arrival. It was at the Kilkenny, site of the earlier now infamous meetup. When I arrived Chris, Laura and Jun were already there. Later on Roland, Alan, Bea, Gareth, Eric, and Chandresh all arrived. We caught up, admired photographs, distributed some NASA goodies I had brought, and shared nachos. I was excited to learn from Jun that the colors of STEVE, particularly the picket fence were not visible to the naked eye. We discussed the chance of a small event that evening due to the arrival of a coronal hole with high speed solar wind. Bea, Laura, and I (all scientists) made a plan to try to go out together.

Alan, Chris, Jun, Laura, Liz, and Roland at the Kilkenny

Rory was a little hungry having been on airplanes all day.

We talked for 3 hours… then I took a long nap. I awoke and started texting Laura and Bea. Would we really meet up? How so? I was on the fence but decided to go for it, since the data were looking so good and since Laura and Bea had never seen aurora before. Also, I really wanted to see STEVE of course, though I knew that was not very predictable. The plan was elaborate but worked well. I caught the same C train Bea was already on, and we proceeded to the Tuscany end of the line. There we were met by Laura and started to drive further from city lights. Soon we were pulled off the road staring at the sky, fiddling with the tripod… we weren’t so successful and decided to proceed immediately to “the” spot recommended by Chris, the Twisty Road Pond. And Chris Ratzlaff himself was there along with ducks and frogs singing spring songs. There were lots of cars and people with lawn chairs. It was an aurora party, albeit a quiet one! And the aurora was a faint quiet arc glowing on the horizon. STEVE had shown up further East earlier in the night, and just the faintest remnants were visible according to Chris. It was a good night to practice with one’s camera. With Chris’ expert advice, Laura was soon lining up in focus aurora and stars plus nice reflections in the pond. We played with some selfies and generally had a great time. Since we are scientists not aurora chasers (and since I had to get up for the ski bus in the morning) we didn’t have much stamina and left early, just before 1 am. It was remarkably quick to get back into Calgary. Shortly after we left more people showed up and a substorm exploded of course. It was AMAZING how close it was and how many people were there. I was super excited to learn in person how relatively easy (and still under-recognized) it is to spot aurora from Calgary.

Laura made her first report to Aurorasaurus.

One of Laura’s best shots of the quiet arc that hung out with us. (Photo credit: Laura Mazzino)

The next day I did make the ski bus and met up with my skiing buddy aka U.C. Prof. Dave Knudsen. The snow and spring conditions were fantastic. Our legs and noses were burning and there was still time for a long nap when we quit. This was was great because the storm was ongoing. I met up with Los Alamos colleagues in Banff, and told them I would send an email if there was a chance for aurora chasing. I was excited because two of these colleagues had never seen aurora and I knew there was a good chance. Once I figured out that a nearby viewing place was only 20 minutes from our hotel, I knew we had to try.

Liz & Rory enjoying fine Canadian spring skiing at Sunshine. Photo by Dave Knudsen.

We had one full car and went to Lake Minnewanka, the Banff equivalent to Twisty Road Pond, around 10:45. We went around the lake, and there weren’t many cars. But as soon as we got out of the car around 11:10 pm and looked up, I thought that might be STEVE. A few moments later, as I saw the broad light silver arc moving gracefully across the sky, I knew it was STEVE! I felt so incredibly lucky to be seeing it, I couldn’t believe my eyes. More cars showed up and we watched STEVE move and slowly shift south for almost an hour. The aurora was to the north but not doing too much there. Only one of the 5 scientists had a camera and she valiantly tried to get some good shots but her camera was acting up. You could not see the different colors by the naked eye but I knew they were there. I could tell that the picket fence structure was there and moving. It was a spectacular night to watch @STEVEphenomena, captured in this Twitter moment. When we showed up the arc was covering the Big Dipper directly overhead, and by the time we left, it was just entirely below the Big Dipper. It was definitely there the whole time and dynamically moving, even showing a bit of high speed flickering at one point. “How did we miss this?” I thought, thinking of our paper showing that STEVE actually corresponds to a subauroral ion drift (SAID). There are many reasons… but that is the topic of another post. It is notable however, that the STEVE structure is quite white to the naked eye and the different purple and green features cannot be distinguished though they can both be seen.

Christine Gabrielse captured STEVE and the picket fence.

We had a good conversation with a friendly security guard who was also watching the STEVE. He told us how there is a flooded town at the bottom of the lake, and said he enjoyed our nerdy talk about what causes the aurora. The next night, it was raining. On the last night, 3 cars of scientists and significant others turned out to try to see the aurora. But it was not in the cards, unless we were to stay out until 2 am. We were not too prepared for the weather and had the meeting the next day though, so we just enjoyed seeing the brightness of Jupiter and had a fun night-time selfie on the lake. In the days since then, this particular high speed stream has persisted and produced at least 3 more visible STEVEs, likely because high speed streams of solar wind are particularly good at producing substorms and SAIDs are associated with substorms.

Eager aurora watchers and scientists from around the world. Photo by Christine Gabrielse

This weekend has capped off the recent publication of the STEVE paper, in the most spectacular and gratifying way. I was in town for work, at a very small workshop in Banff. Ironically at that workshop we talked about how difficult it is to know (in space, in the magnetosphere) what causes even the most straightforward of auroral forms, like the quiet arc. We are working on new techniques to aid with understanding how the visible aurora maps to the drivers far out in space. And now, more of us know what we are looking for.

STEVE (Strong Thermal Emission Velocity Enhancement) is seen as a thin purple ribbon of light.
Credit: ©Megan Hoffman

Notanee Bourassa knew that what he was seeing in the night sky was not normal. Bourassa, an IT technician in Regina, Canada, trekked outside of his home on July 25, 2016, around midnight with his two younger children to show them a beautiful moving light display in the sky — an aurora borealis. He often sky gazes until the early hours of the morning to photograph the aurora with his Nikon camera, but this was his first expedition with his children. When a thin purple ribbon of light appeared and starting glowing, Bourassa immediately snapped pictures until the light particles disappeared 20 minutes later. Having watched the northern lights for almost 30 years since he was a teenager, he knew this wasn’t an aurora. It was something else.

From 2015 to 2016, citizen scientists — people like Bourassa who are excited about a science field but don’t necessarily have a formal educational background — shared 30 reports of these mysterious lights in online forums and with a team of scientists that run a project called Aurorasaurus. The citizen science project, funded by NASA and the National Science Foundation, tracks the aurora borealis through user-submitted reports and tweets.

The Aurorasaurus team, led by Liz MacDonald, a space scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, conferred to determine the identity of this mysterious phenomenon. MacDonald and her colleague Eric Donovan at the University of Calgary in Canada talked with the main contributors of these images, amateur photographers in a Facebook group called Alberta Aurora Chasers, which included Bourassa and lead administrator Chris Ratzlaff. Ratzlaff gave the phenomenon a fun, new name, Steve, and it stuck.

But people still didn’t know what it was.

Scientists’ understanding of Steve changed that night Bourassa snapped his pictures. Bourassa wasn’t the only one observing Steve. Ground-based cameras called all-sky cameras, run by the University of Calgary and University of California, Berkeley, took pictures of large areas of the sky and captured Steve and the auroral display far to the north. From space, ESA’s (the European Space Agency) Swarm satellite just happened to be passing over the exact area at the same time and documented Steve.

For the first time, scientists had ground and satellite views of Steve. Scientists have now learned, despite its ordinary name, that Steve may be an extraordinary puzzle piece in painting a better picture of how Earth’s magnetic fields function and interact with charged particles in space. The findings are published in a study released today in Science Advances.

“This is a light display that we can observe over thousands of kilometers from the ground,” said MacDonald. “It corresponds to something happening way out in space. Gathering more data points on STEVE will help us understand more about its behavior and its influence on space weather.”

The study highlights one key quality of Steve: Steve is not a normal aurora. Auroras occur globally in an oval shape, last hours and appear primarily in greens, blues and reds. Citizen science reports showed Steve is purple with a green picket fence structure that waves. It is a line with a beginning and end. People have observed Steve for 20 minutes to 1 hour before it disappears.

If anything, auroras and Steve are different flavors of an ice cream, said MacDonald. They are both created in generally the same way: Charged particles from the Sun interact with Earth’s magnetic field lines.

Credits: NASA Goddard’s Conceptual Image Lab/Krystofer Kim

Specifically, the aurora and STEVE creation process starts with the Sun sending a surge of its charged particles toward Earth. This surge applies pressure on Earth’s magnetic field, which sends the Sun’s charged particles to the far side of Earth, where it is nighttime. On this far, night side of Earth, Earth’s magnet field forms a distinctive tail. When the tail stretches and elongates, it forces oppositely directed magnetic fields close together that join in an explosive process called magnetic reconnection. Like a stretched rubber band suddenly breaking, these magnetic field lines then snap back toward Earth, carrying charged particles along for the ride. These charged particles slam into the upper atmosphere, causing it to glow and generating the light we see as the aurora — and now possibly STEVE.

The uniqueness of Steve is in the details. While Steve goes through the same large-scale creation process as an aurora, it travels along different magnetic field lines than the aurora. All-sky cameras showed that Steve appears at much lower latitudes. That means the charged particles that create Steve connect to magnetic field lines that are closer to Earth’s equator, hence why Steve is often seen in southern Canada.

Perhaps the biggest surprise about Steve appeared in the satellite data. The data showed that Steve comprises a fast moving stream of extremely hot particles called a sub auroral ion drift, or SAID. Scientists have studied SAIDs since the 1970s but never knew there was an accompanying visual effect. The Swarm satellite recorded information on the charged particles’ speeds and temperatures, but does not have an imager aboard.

“People have studied a lot of SAIDs, but we never knew it had a visible light. Now our cameras are sensitive enough to pick it up and people’s eyes and intellect were critical in noticing its importance,” said Donovan, a co-author of the study. Donovan led the all-sky camera network and his Calgary colleagues lead the electric field instruments on the Swarm satellite.

Steve is an important discovery because of its location in the sub auroral zone, an area of lower latitude than where most auroras appear that is not well researched. For one, with this discovery, scientists now know there are unknown chemical processes taking place in the sub auroral zone that can lead to this light emission.

Second, Steve consistently appears in the presence of auroras, which usually occur at a higher latitude area called the auroral zone. That means there is something happening in near-Earth space that leads to both an aurora and Steve. Steve might be the only visual clue that exists to show a chemical or physical connection between the higher latitude auroral zone and lower latitude sub auroral zone, said MacDonald.

“Steve can help us understand how the chemical and physical processes in Earth’s upper atmosphere can sometimes have local noticeable effects in lower parts of Earth’s atmosphere,” said MacDonald. “This provides good insight on how Earth’s system works as a whole.”

The team can learn a lot about Steve with additional ground and satellite reports, but recording Steve from the ground and space simultaneously is a rare occurrence. Each Swarm satellite orbits Earth every 90 minutes and Steve only lasts up to an hour in a specific area. If the satellite misses Steve as it circles Earth, Steve will probably be gone by the time that same satellite crosses the spot again.

In the end, capturing Steve becomes a game of perseverance and probability.

“It is my hope that with our timely reporting of sightings, researchers can study the data so we can together unravel the mystery of Steve’s origin, creation, physics and sporadic nature,” said Bourassa. “This is exciting because the more I learn about it, the more questions I have.”

As for the name “Steve” given by the citizen scientists? The team is keeping it as an homage to its initial name and discoverers. But now it is STEVE, short for Strong Thermal Emission Velocity Enhancement.

Other collaborators on this work are: the University of Calgary, New Mexico Consortium, Boston University, Lancaster University, Athabasca University, Los Alamos National Laboratory and the Alberta Aurora Chasers Facebook group.

If you live in an area where you may see STEVE or an aurora, submit your pictures and reports to Aurorasaurus through aurorasaurus.org or the free iOS and Android mobile apps. To learn how to spot STEVE, click here.

Photo credit: Robert Michell

Above our heads, the aurora provides one of the biggest and best light shows on Earth. The light moves about, flashes across the sky, similar to some of the types of man-made lights we are familiar with. However, this light show isn’t to set the mood for a party. It holds information about the physics surrounding Earth. By studying pulsating and flickering auroral morphology, scientists can gain valuable knowledge about the magnetosphere and electromagnetic waves surrounding the planet.

As a summer intern at NASA Goddard Space Flight Center, I arrived not really knowing anything about the features of the aurora. However, as I spent the summer searching for instances of flickering and pulsating aurora over millions of images of the sky, I began to understand the science behind the famous natural light show and the features that it presents. Although there are aspects of these types of aurora that some experts still don’t understand, the overarching concepts are as simple as knowing the difference between groovy lava lamps and energetic strobe lights.

What is “Morphology”?

When studying auroral morphology, we are examining how the aurora changes physically over space and time. Since the aurora is dynamic, its shape is constantly evolving over various time scales. It appears to stretch, condense, and sometimes fluctuate in brightness or intensity, hence the common description of the aurora “dancing across the sky.” Some of this dynamic behavior can be categorized into different types of aurora, such as flickering and pulsating aurora. Although both of these terms seem to be describing the same sort of activity, they differ in both origin and appearance.

Pulsating Aurora – The Lava Lamp

As described in another Aurorasaurus blog post from 2015, the term “pulsating aurora” is used to describe aurora that periodically fluctuates in brightness.

It occurs when particles travel over magnetic field lines in space, bouncing between the North and South pole rather like a game of ping pong. When they are closer to the poles, the particles speed up and change direction in a process called “mirroring.” This continues until other electromagnetic waves become involved, called very low frequency waves or VLF waves. These waves interact with the particles, changing the mirroring points so that they are closer to Earth’s surface, and lowering the hypothetical ping pong paddles down to the level of the atmosphere. Once these particles reach this height, they interact with Earth’s atmosphere and are lost from the space ping pong game. Instead, they collide with particles in the atmosphere and create the pulsating features seen in the aurora. The very low frequency waves are unique to this type of aurora and to the characteristic on/off behavior.

The resulting light show can be compared to the glowing behavior of a lava lamp. Distinct areas and patches of the pulsating aurora periodically get brighter and dimmer. This is similar to how the colorful fluid inside a lava lamp shifts and glows in obvious clumps, shining brightly for a bit before dispersing. The pulsating patches can vary in size, just like the light dollops inside a lava lamp, although the aurora patches are on the scale of 10-100 km (just a little too big to fit on a bedside table). Also, the relaxing and sluggish movement of material in the lamp reflects the timescale of the pulsating aurora. These fluctuations usually occur over the scale of one to ten seconds. This gradual change in brightness makes the aurora act as Earth’s very own lava lamp, stretching across the night sky and providing a natural, groovy, glow.

Flickering Aurora – The Strobe Light

Flickering aurora is created under different circumstances. There is a constant stream of electrons passing into Earth’s atmosphere and making the aurora. This stream of electrons can be disturbed by electromagnetic ion cyclotron waves, or EMIC waves. The electrons descend into the atmosphere, ready to collide with other particles and form the aurora. Suddenly, EMIC waves come screaming in, knocking some the electrons off course. This disturbance leaves small gaps in the electron stream and causes the features seen in flickering aurora.

The relaxing mood lighting provided by the pulsating aurora lava lamp is gone, only to be replaced by the flickering aurora’s energetic fluctuations, similar to a vigorous and sometimes disorienting strobe light. The intensity variation is much quicker, flashing on and off about five to ten times per second. It also covers an area of the aurora much smaller than the pulsating aurora, on the scale of only a few kilometers. It’s also believed that this quick flickering originates much closer to the surface of the Earth than the origins of the pulsating aurora, only 3 to 5 thousand kilometers off the ground. More research is currently being done on the flickering aurora, trying to capture it in data as it shutters bright and dim over the course of fractions of a second, creating the ambiance for nature’s own concert and magic show.

The Educational Light Show

Photo credit: Robert Michell

At the conclusion of my internship, I had found about 7 instances of flickering aurora and 2 hours worth of pulsating aurora. Once I found these features, I was able to analyze the camera images of them to measure their intensity, position, and velocity. Eventually these measurements will be used to compare the flickering and pulsating aurora from this location in

Greenland to auroral features present at lower latitudes such as Alaska and Montana. The images I analyzed were captured with a ground-based camera. It sat night after night in Greenland, pointing up at the night sky and continuously taking photos. It was a lot of data to sift through to find nights that were not cloudy and showed bright aurora, and even more work was needed to search these times to find the flickering and pulsating features. The timescale of these features make them a challenge for citizen scientists to capture by camera, but they can be noticed by eye if one knows what to look for.

Spending time studying and researching these auroral features helps bring about a greater understanding of the magnetosphere, and allows scientists to create more accurate magnetic field models. Since all of the dynamic processes that occur within the magnetotail are mapped through the aurora at the polar caps, understanding every single feature, on time scales ranging from of fractions of seconds to hours, gives us a blueprint of the physics occurring within this region of magnetic field lines which protect us from some of the sun’s electromagnetic radiation.

Shows key differences between pulsating and flickering auroras. Created by Michelle Tebolt.

Michelle Tebolt was a summer intern at NASA Goddard Space Flight Center in 2017. She is an astrogeophysics major at Colgate University going into the third year of her undergraduate degree. She is enthusiastic about all things astronomy, geology, and physics related, including the aurora and its features. Contrary to what this article suggests, she does not own a lava lamp.

A common misconception about the aurora is that it’s formed by particles streaming straight from the sun.  This graphic, published by USA Today, offers an explanation that’s probably similar to one you’ve heard before:

Caption: What’s wrong with this picture? Read on!

The graphic focuses primarily on the solar wind, or the continuous flow of plasma — a high-temperature mix of charged particles — from the sun.  But while the solar wind is essential to understanding auroras, there are other factors involved in creating these celestial light displays. By only considering the solar wind, we leave some key questions unanswered.  For example, why do we see the aurora at night (when we’re facing away from the sun)?

Before we can tackle that, we need to recognize that charged particles aren’t the only things the sun sends us.  The sun is actually a giant magnet — and just like an ordinary bar magnet, it has a north and a south pole, with invisible magnetic field lines stretching from one to the other.  As scientists first discovered in the 1800s, electricity and magnetism have a very special relationship with each other.  A defining feature of this relationship is that electric charges can’t cross magnetic field lines.  Instead, they spiral around them, like this:

A charged particle (green dot) in a magnetic field (B) spirals around the magnetic field lines in a circular orbit with radius r.
By Maschen (Own work) [CC0], via Wikimedia Commons

You can think of the particles as being “trapped” by the field lines.  And that’s precisely what’s happening in the solar wind!  Bound up in the plasma are bits of the sun’s magnetic field.  Earth is a giant magnet, too, and ultimately it’s the interaction between the sun’s magnetic field and Earth’s that leads to the aurora.  The underlying mechanism of that interaction, which transfers energy between the two fields, is known as magnetic reconnection.

The idea behind reconnection is fairly simple:  magnetic field lines meet, break off, and form connections with other field lines.  But what does that mean, exactly?  Have a look:

By ChamouJacoN (Own work) [Public domain], via Wikimedia Commons

Each magnetic field line has a direction (as indicated by the arrows).  By convention, we say that a magnet’s field lines extend from the north pole to the south pole.  (Fun fact:  the Earth’s geographic north pole is actually its magnetic south pole.) Reconnection occurs when opposing field lines come into contact.

Now let’s jump back to the USA Today graphic.  See how Earth’s magnetic field is depicted there?  It’s a gray circle, with Earth in the middle.  In reality, it looks more like this:

By NASA (http://sec.gsfc.nasa.gov/popscise.jpg) [Public domain], via Wikimedia Commons

When the solar wind hits Earth’s magnetic field, the wind slows down dramatically, creating a shock wave called the bow shock.  The bow shock diverts the stream of charged particles (and the magnetic field it carries) into paths that run alongside Earth’s magnetic field.  In certain spots, the solar and planetary magnetic fields point in opposite directions, and reconnection takes place.  The resulting new field lines — a combination of the sun’s and Earth’s — are swept back toward the magnetotail.  

The process is a bit like swimming breaststroke in an endless pool within the ecliptic plane.  We’ll explore that analogy further in an upcoming post.  Stay tuned!

So why does aurora happen when we’re facing away from the sun? Reconnection also happens on Earth’s night side.  As the energy from the solar wind is transferred into the magnetotail, it interacts with the charged particles already trapped there.  When opposing field lines approach one another in the magnetotail, a portion of the magnetic field pinches off into space.  The rest, meanwhile, snaps back toward us.

As the charged particles accelerate toward Earth’s poles, they pick up even more energy.  Once they slam into the atmosphere, that energy is transferred to the atoms they encounter.  But the atoms can’t hold on to that extra energy for long — so they re-emit it as light.  The color of the light corresponds to the amount of energy absorbed by a given atom, as well as the type of atom it is.  Oxygen, for example, can produce either green or red emissions, whereas nitrogen’s are generally violet or blue.

These emissions are what we perceive as the aurora.

Now you know the real story:  magnetic reconnection in the magnetotail is why you can see the aurora even when you’re facing away from the sun.  Nighttime auroras cannot be explained by the solar wind alone!  The magnetosphere is a complex jungle of plasma, and it’s the greatest physics lab we can actually sample so let’s make sure we give credit where credit is due!

Bio:  Kristine Romich interned in the Heliophysics division at NASA’s Goddard Space Flight Center in the summer of 2017.  Her research investigated the heating of the solar corona.  While at Goddard, she also began volunteering with the Aurorasaurus citizen-science project as a guest blogger.  Kristine earned her A.S. degree from the City Colleges of Chicago in 2016 and will continue her studies in physics at California State University – Northridge this fall.

Learn more at our Twitter #citscichat with Dr. Caren Cooper (@CoopSciScoop) on Aug 17 at 4 pm ET.
Participants from most of the projects highlighted here will participate.

Over a century ago, American astronomer W.W. Campbell set up a 40 foot ‘Schaeberle camera’ in Jeur, India to take pictures and study various properties of the sun’s outermost layer called the corona during the 1898 total solar eclipse. To make sure no people or animals would tamper with the camera before the eclipse occurred, he found volunteers to guard the delicate equipment the evening before the experiment. Today, in 2017, volunteers called citizen scientists are again helping scientists make observations and learn more about the sun and Earth interaction. This time though, citizen scientists across the United States will have more direct involvement, actually collecting data by making their own observations and operating instruments.

Studying the corona

Using a modern solar telescope, citizen scientists will operate the equipment to further answer questions about the sun’s corona, such as what causes its extremely high temperature. Scientists are interested in learning more about the corona because it can send off explosions called coronal mass ejections towards our home planet that can interact with our power grid systems, for instance. The corona is extremely difficult to measure outside of a solar eclipse because it is usually blocked out by the brightness of the sun’s surface.

The two towers of the Schaeberle Camera and the rock wall at Jeur, India, with overall height lowered by use of a pit for the plateholder. Source: Mary Lea Shane Archives

For this eclipse, the Citizen Continental-America Telescopic Eclipse (CATE) project recruited the public to make observations of the corona while the sun is blocked out by the moon. Over 60 volunteer observing teams across the path of totality across the United States will combine their individual two minute observations to make a continuous 90 minute movie of the white solar corona. Participants, including students from 22 high schools, have already been selected and trained.
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With more amateur-level equipment, the Google sponsored Eclipse Megamovie team enlists the help of the public to take pictures of sun. The project will create a spectacular “Megamovie” with all of the observations. Their website also has a great easy-to-use simulator of the eclipse with a helpful timeline. Unlike the Citizen CATE project, this project uses consumer grade equipment (like their app on your smartphone!), which could bring in a million observations from users!

Studying Space Weather

The eclipse also provides a special opportunity to learn more about “space weather” that affects Earth and satellites. When you see the solar corona, you see what causes “space weather.” Earth’s upper atmosphere called the ionosphere is charged by the sunlight hitting it and this will change rapidly during an eclipse. Those changes affect the density and temperature of different layers of the atmosphere differently. Various types of space weather can block high-frequency radio waves for radio communication, disrupt satellites, and degrade Earth’s power grid operations. It can also cause beautiful aurora (which is what our citizen science project Aurorasaurus tracks!).

Aurora over Earth. Source: NASA

On August 21st, citizen scientists will help record changes in Earth’s upper atmosphere. Two projects are focused on these effects. The first, called HamSci, uses the vast network of ham radio, or amateur radio, enthusiasts. Ham radio allows people to talk to one another without internet or cell phones. Ham radios operate in short-wave bands which “bounce” from the transmitter off the ionosphere to the receiver’s antenna. Creating similar effects as nightfall, the eclipse’s shadow alters the ionosphere, which affects radio wave communication and are useful for the study of ionospheric physics.

In HamSci, ham radio enthusiasts will participate in a large scale experiment to operate and make observations during the eclipse. Scientists do not quite know how the eclipse will change the upper atmosphere so collecting as much data as possible will be valuable.The HamSci project will analyze these observations for their scientific content relating to the height and density of the upper atmosphere. Ham radio operators will participate in a contest to take as many observations before, during, and after the eclipse.

For those who are not ham radio enthusiasts, a project called EclipseMob uses the same concept, but different equipment. In fact, you build your own antenna that captures radio signals from the air and feeds them into the receiver. They will be sensitive to different regions using different wavelength wave and different dynamics. You can learn more about EclipseMob and order instrument parts here.

Studying Earth during the Eclipse

Closer to home, “normal” weather is also affected by the eclipse. First, the lack of sunlight cools the Earth. The rapidly moving dark shadow can also change clouds and winds. You can report on these changes with NASA’s GLOBE Observer app. This is part of the larger worldwide GLOBE program, Global Learning and Observation to Benefit the Environment. When using the app, you’ll want to look around at the landscape changes as well as the Sun. You can also see what NASA Earth observing satellites are seeing and if they are seeing the same clouds as you. Your observations help calibrate those satellites.

But, what about plants and animals? While they don’t know an eclipse is happening, they may sense some of the effects. Thomas Jefferson remarked on the lightning bugs he observed in 1778. Now, there is a citizen scientist project, called Life Responds part of the iNaturalist program, to move our knowledge from anecdotes to the rigorous scientific method. Through this project, data will be collected at a global scale to more robustly observe the changes.

Another project, called the Quantum Weather Project, will also launch weather balloons and asks for observations of shadow bands, mysterious optical phenomena you can see right before totality.

No matter your interest or experience level, the eclipse is an unprecedented opportunity to participate in real science experiments! Observe these remarkable changes, and use your enthusiasm to help increase our collective understanding of the natural world. For more information, a great website where you can find these projects and more is eclipse2017.nasa.gov.

If you’re not around the United States for the August 21st eclipse, you can still see it livestreamed on the NASA website. The NASA Space Grant Network is funding a unique project this summer for the total solar eclipse. Students teams will be conducting high altitude balloon launches from different locations along the eclipse path. The items carried on the high altitude balloons will be live streaming the eclipse to the NASA website from near space and sending images. Live streaming a total solar eclipse has never been done live and will be extensive as a network of teams will be stretched over many states.

Lastly, what if you want to participate in more citizen science projects and can’t wait until the next solar eclipse? Check out Aurorasaurus, a citizen science project, aimed at the aurora, another part of space weather. Aurora chasing is like eclipse chasing, but harder to predict. Or participate in International Observe the Moon night on Oct. 28, 2017 to build on your eclipse experience!

Thanks to all of the sponsors and of course, you, the curious citizen scientist super heroes who will make it happen!

Links to mentioned citizen science projects:

• Citizen Continental-America Telescopic Eclipse (CATE)
• Eclipse Megamovie
• HamSci
• EclipseMob
• NASA’s GLOBE Observer app
• Life Responds part of the iNaturalist program
• Aurorasaurus, aurora hunting citizen science project

What do fidget spinners, the latest fad toy and new student favorite, have to do with the upcoming solar eclipse? Teachers don’t despair, fidget spinners can demonstrate physics concepts and orbital mechanics for kinesthetic learners. The eclipse is all about gravity, and the rotation of celestial bodies. As the fidget spinner spins about its central axis, an object on the arm of the spinner (or two or three) is locked in rotation around the central object. Much like the Earth rotates around the Sun. So for that, picture a solar fidget spinner 93 million miles from the center to the edge!

We are on a giant fidget spinner, rotating once per year, smoothly going around the Sun for billions of years in the “ecliptic” fidget spinner plane. Sped up for galactic time, it looks just like this:

Now zoom in on the Earth. It has its own fidget spinner, the Moon which rotates around the Earth! The arm of that extraterrestrial fidget spinner is “only” 250,000 miles. The Moon rotates once every 27 days for 4.5 billion years (just a little younger than the Earth). And here’s the key to understanding eclipses, the lunar fidget spinner is tilted like so, 5° out of the ecliptic Sun-Earth plane.

So try to picture these two huge fidget spinners with different periods, size, and tilt. When they line up a total solar eclipse can be caused! They intersect only rarely but there is a pattern to some of those intersections. It’s 18 yrs ten and one third days. More about that pattern here (Saros cycle) and in the next post.

Finally, there’s one more similarity between your average fidget spinner and celestial orbital mechanics. Gravitationally driven celestial fidget spinners go for cosmically long times, but they also have tiny deviations and wobbles, just like your fidget spinner might (look at it edge on, and you may notice some small wiggles). The Earth and the Moon are not perfect spheres, and their orbits are not perfect circles. So there’s a little bit of variation in their spinning, due to minute manufacturing differences, just like that spinner you got from 7-11. The moon usually looks like a perfect circle, but during a solar eclipse, some of the features you see like Bailey’s Beads and the “diamond ring” effect are actually due to its not being a perfect sphere, but being heavily cratered.

Activity ideas:

1. Close your eyes and picture a huge solar fidget spinner.
2. Draw it. Spin it. Label the Sun and the Earth,
3. Close your eyes and picture the smaller lunar fidget spinner going around the Earth.
4. Draw it. Spin it. Be sure to have the tilt.
5. Now put those two drawings together to illustrate the eclipse.
6. Last, look at your fidget spinner edge on. Do you see the way it isn’t perfect?
7. If you put a flashlight behind it, do you see those better?

Extras:

Kids could use the fidget spinner during the eclipse as a pinhole projector.

No fidget spinner, no problem. Try it here: http://ffffidget.com/

The aurora is well-known to the savvy Aurorasaurus observer – fanciful colored lights in the sky caused by charged particles energizing the atmosphere near the North and South poles. But did you know that you can observe aurora as far south as Arizona? Or that the sky still glows at night in the absence of any aurora? For the first time, a new project is capturing these rare events with affordable cameras located in high schools across the United States, also enabling space-science education.

The Midlatitude Allsky-imaging Network for GeoSpace Observations (MANGO) captures these atypical  observations of upper atmospheric airglows and low-latitude auroras, and applying image processing algorithms to correct distortions and to eliminate background noise.  This system will be used to study macroscopic-scale auroras and airglows over the country and to characterize the dynamics of charged particles in the ionosphere. The processed images are then geo-located on a map of the United States for real-time display on the project website for anyone to use- check it out!

What are stable auroral red arcs (SAR) and air glow?

MANGO is used to study propagating waves in the upper atmosphere, called traveling ionospheric disturbances (TIDs), expansion of auroral oval to lower latitudes and stable auroral red (SAR) arcs, which occur during extreme geomagnetic conditions.

During strong geomagnetic storms, aurora that is typically confined to high-latitudes moves to lower latitudes as Earth’s magnetic field becomes stressed and compressed. Additionally, rarely, during geomagnetic storms, the Van-Allen radiation belt regions move closer to Earth and cause large-scale generally sub-visual displays of red (630 nm) emission at mid-latitudes. These relatively stable displays are known as Stable Aurora Red (SAR) arc and can be observed stretching from Massachusetts to Washington.

Air glow originates when the neutral gases (oxygen, nitrogen, sodium) in Earth’s upper atmosphere receive a high dose of ultraviolet energy from the sun during the day. This energy causes electrons and ions in the neutral gas molecules and atoms to separate and the upper atmosphere is flooded with charged and excited particles. These charged and excited particles are constantly recombining to get back to their neutral state. As the particles recombine or return to unexcited states, they may release a photon in the visible wavelength range. The color of this visible light depends on the gas molecule or atom involved. This light is known as airglow and is visible as a blanketing layer around the earth. During the day, scattered light from the sun itself is much brighter than the airglow process and it is very challenging to observe. At night however, when the sun is below the horizon, the sky is dark enough for airglow to be easily detected by cameras with long exposures and good filters. Observing slight variations in the airglow layer gives information about disturbances in the upper atmosphere at night that are poorly documented.

How does MANGO capture SAR and airglow?

Although these phenomena span continents, optical observations over North America have been conducted only at isolated camera sites, and a global-scale view did not exist.

MANGO is a collection of seven cameras spread across the continental United States with the goal of imaging large-scale airglow and aurora features. These cameras form a network providing continuous coverage over the western United States, including California, Oregon, Washington, Utah, Arizona and Texas, and extending south into Mexico. MANGO observes the generation, propagation, and dissipation of medium and large-scale wave activity in the subauroral, mid and low-latitude thermosphere. The project is funded under a National Science Foundation grant at SRI International.

An all-sky camera has a maximum field-of-view of 1200-1500 km2 at ionospheric altitudes between 250 and 350 km, making this instrument an excellent ground-based observing tool to monitor large-scale dynamics in the ionosphere. The combined view from multiple cameras can be used to image continent-scale structures and provides an unprecedented coverage of ionospheric airglow dynamics in the continental United States. In the image above, diffuse aurora (or aurora over a large area) can be seen in the cameras in Montana and Iowa, while wave like structure is seen in the California and Utah cameras. Such a mosaic gives us a view of coupling between regions that have different manifestation of same geomagnetic processes.

Each camera in the MANGO network has a red filter centered at 630 nm with a view of the entire sky. Designed for low-cost ease of replication, each system is configured entirely from off-the shelf parts with an amateur astronomy-grade camera as the detector. Images are acquired every five minutes and are stitched together to provide a mosaic view of airglow across the entire United States.

Because nighttime imaging of faint emissions from the sky requires really dark skies, the MANGO team has partnered with several amateur astronomy observatories and schools in rural areas across the United States to install the MANGO cameras. These are high schools in Bridger, Montana and Madison, Kansas and Hat Creek Radio Observatory, California; Capitol Reef Field Station, Utah; Palisades-Dows Observatory, Iowa; Rainwater Observatory, Mississippi; and Pisgah Astronomical Research Institute, North Carolina. The MANGO team visited the high schools and gave a seminar to the science teachers and students on space weather followed by hands-on activities centered around dipole magnets and compass that teach the students the importance of earth’s own magnetic field. Most of the observatory partners are themselves non-profit and amateur astronomy observatories that provide amazing support for scientific researchers.

If you’re an Aurorasaurus user, you will want to check out this new real time resource.

Questions about MANGO? Contact mango@sri.com

 
Update 4/25/17 (by Liz MacDonald):

Steve has gone viral! Check out the articles here.

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There’s a new dancing light display in the sky, and it’s not the usual aurora. We need your help to learn more!

Giving off a glow in mostly purple and green colors, the phenomenon was observed by members of a Facebook group called the “Alberta Aurora Chasers” who named the display “Steve.” Why Steve? Well, this is a reference to the popular children’s movie Over the Hedge where one of the characters isn’t sure what he is looking at and randomly names it Steve. Steve was formerly called by aurora chasers and photographers a “proton arc” (also known as a proton aurora). Proton aurora, or aurora caused by the raining down of protons from the magnetosphere is broad, diffuse, and dim visually unlike the structure of Steve that is narrow and has motion. So we know it is not a proton arc although we do not yet fully know what it is.

More than 50 observer reports have been seen in 2016 and we are hoping for more in 2017. We’re working with Canadian and European researchers, data providers, and the Ambassadors network on this and will bring you more information as we know more. Space scientists from NASA, the University of Calgary and other places are already trying to make Steve an acronym meaning “Strong Thermal Emission Velocity Enhancement” based on its characteristics from simultaneous satellite observations.

We are are still learning more about Steve, but here are seven things we think we know so far:

1. Steve appears ~10-20° (in latitude) closer to the equator (south in the Northern hemisphere) than where the normal green aurora is overhead. This means it could be overhead at latitudes similar to Calgary, Canada.
2. Steve is a very narrow arc aligned East-West and extending for hundreds or thousands of miles.
3. Steve emits light in mostly purple-ish colors. It is quite faint but is usually photographed with 5-10 second exposures.
4. Sometimes, it is accompanied by a rapidly evolving green short-lived picket fence structure.
5. Steve can last 20 min or even longer.
6. Steve appears to have a season. For instance, it has not been observed by citizen scientists from October 2016 to February 2017.
7. This phenomena has been reported from the UK, Canada, Alaska, northern US states, and even New Zealand.

As we are still learning more about this unique phenomenon, reports from citizen scientists have been immensely helpful in tracking down the shape, location, and timing of Steve and giving clues to scientists about the origin of this mysterious piece of chemistry in the sky. Until then, keep submitting your observation to Aurorasaurus.org via the website or Aurorasaurus app.

Michael S. Kirk

Image of the sun from the Solar Dynamic Observatory with darker regions, known as coronal holes, labeled. Source: NASA

When we look at the lowest and middle layers of the sun, it appears relatively uniform with small dark (sunspots) or bright (active regions) blemishes. However when we look at the outermost layer of the sun’s atmosphere, the corona, something bizarre happens – large chucks appear to be missing. These large dark regions are called coronal holes and are some of the most fascinating solar features we routinely observe.

Both casual and scientific descriptions of coronal holes have been documented as far back as the early 1900s during solar eclipses. They were first noticed as rays of light streaming out from the solar poles, which appeared similar to the magnetic field lines of a bar magnet.  The first direct images coronal holes on the disk of the sun didn’t start until early in the space age. In the late 1960s and early 1970s, they could be seen as isolated dark patches in UV and x-ray images. The definition of these dark patches was refined to be what we know now as coronal holes by solar instruments on the Skylab space station in 1973 and 1974. The Skylab data and subsequent rocket missions helped to define characteristics of these holes. They routinely appear as dark caps in both the north and south poles of the sun and as large, often stretched-out, expanses in mid-latitude and equatorial regions.

Above: Images of coronal holes from Skylab. Credit: NASA

One of the most fascinating aspects of coronal holes is that they are some of the most persistent features on the sun. The mid-latitude and equatorial holes typically last for at least a few months and up to nearly a year. Polar coronal holes can endure for several years at a time. In fact, polar coronal holes completely disappear only at solar maximum for about year before they return as solar activity declines.

Sunspot numbers continue to decline as we approach a solar minimum leading to less coronal mass ejections that could potentially spark geomagnetic activity. During solar minimum coronal holes is the main space weather phenomenon that produces geomagnetic activity. Coronal holes allow for solar wind to escape easily and in result earth experiences enhanced solar wind speeds which in return can spark aurora activity. Don’t worry aurora lovers, solar minimum doesn’t mean the sky will go quiet and we can thank coronal holes for that.

Defining the Coronal Hole

Scientifically speaking, the term “coronal hole” simultaneously refers to three distinct phenomena depending on whom you are talking to. These differing perceptions of coronal holes have the same physical root, yet a one-to-one mapping of features between them has never been accomplished. First, the dark patches that appear in coronal x-ray and ultraviolet images are called coronal holes (just to confuse things, these same regions appear bright in the He I 10830 Å triplet). Second, the lowest intensity regions observed outside the limb of the sun are called coronal holes; these regions were first observed during natural (i.e., the moon) and artificial (i.e, coronagraphs) eclipses. Third, a largely theoretical definition of coronal holes is described, in which coronal holes are explained by open magnetic field lines extending from the solar surface outward into space (the precise length needed for a field line to be considered “open” is up for debate).

All three definitions describe regions of low plasma density occurring in the corona where ionized atoms and electrons are free to flow from the sun’s surface outward into space along magnetic field lines. The reason why coronal holes appear dark is because the hot plasma that typically glows in the corona at millions of degrees is being swept away by the magnetic field. All of this hot plasma being blown out means that coronal holes are the primary source of the fast component of the solar wind that envelopes Earth as well as the rest of the solar system. Understanding the origin of the solar wind is critical in producing accurate space weather forecasts for our satellites, our astronauts, and our planet.

Coronal holes are hard to define not only in scientific terminology, but also in images of solar corona as well. Mapping the shape of coronal holes is kind of like trying to measure the edge of a cloud – it is easy to tell what is definitely a hole and what definitely isn’t, but the boundary is fuzzy and different observers will mark the edge differently. To complicate things further, coronal holes appear differently in different wavelengths. The size, shape, and darkness of any given hole are not consistent between separate observing filters. The theoretical definition doesn’t help much either, since it is dependent on coronal magnetic fields and we currently have no way to independently measure the intensity and location of coronal magnetic fields.

Future Research of Coronal Holes

Like almost every other outstanding issue in observational science, more data is needed to resolve the problems with distinguishing and simulating coronal holes. Ultimately, we need coronal vector magnetic field measurements to link the off-limb regions to dark patches on the disk and to model the physical origin of holes.

Two upcoming solar missions will have the capability to greatly improve our understanding of coronal holes: the ground-based observatory Daniel K. Inouye Solar Telescope and the satellite Solar Probe+. The Daniel K. Inouye Solar Telescope (DKIST) is expected to image the sun in unprecedented detail beginning in 2019. Among the expected capabilities of DKIST’s instrument suite is the ability to image the off-limb corona with enough signal to measure the emerging coronal magnetic fields.

Solar Probe+ will launch in 2018 with an orbit that will come closer to the sun than any manmade object ever has. Solar Probe+ will actually fly through the fast moving plasma and magnetic fields that define coronal holes and make measurements of temperature, magnetic field strengths, and particle density. The combination of both of these new observatories with our current extreme ultraviolet lithography (EUV) imaging satellites will hopefully resolve the ambiguities in coronal holes and ultimately give us the ability to forecast the effects of coronal holes on our planet.

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Dr. Michael Kirk works as solar physicist at NASA Goddard Space Flight Center and is a research associate with Catholic University of America.  His current research include solar image processing, coronal hole mapping, and science communication.