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Mysterious Auroras: The Complicated Awe-Inspiring Northern Lights

  • By Lourdes B. Avilés, Ph.D.
  • Jan 7, 2025

Aurora, 10 May - Zenith View by Lourdes B. Avilés, Ph.D.

Experiencing the aurora borealis (northern lights) has been something I wanted to do for as long as I can remember. Growing up in the tropics, however, it was more of a dream of an adventurous trip to a distant destination: a really cold destination—especially for a tropical girl—where the ability to see them needed the long nights of high latitude winters. Since then, I have spent half of my life right in the middle latitudes, where the lights do make appearances but very sporadically. First at 40°N (Champaign-Urbana, IL while earning my doctorate in atmospheric sciences) and then at 43°N (Plymouth, NH where I have had the pleasure to work at beautiful Plymouth State University for a couple of decades), my prospects were not that great. It still felt like something for which I would have to go out of my way to experience.

I recall one morning over twenty years ago when everyone around me (here in New Hampshire) was talking about the amazing northern lights they saw the previous night. My family and I, however, most definitely missed them. Since then, NOTHING—well maybe one or two faint whitish moving fog-like sights near the northern horizon over the years. That ended in 2024. Suddenly, accessible auroras became more frequent, relatively speaking, and I had not one but TWO opportunities to experience intense, awe-inspiring, full-sky auroras in less than six months (May 10 in central NH and October 10 in Boulder, CO). Let’s review that: zero in 54 years, and two in six months! What happened? Was it that I am more knowledgeable and connected than I was before? I have written a textbook chapter about the science of the aurora (not published yet); I have certainly learned much about the phenomenon, so yes there is some of that, but there is much more! The key to my newly found luck is that we have been rapidly heading toward a solar maximum, during which aurora activity tends to increase. Before I tell you more about that and about my adventures, let’s go over some of the basics: the what, where, when, and how of auroras.

On May 10, 2024 I finally had the opportunity to see an intense aurora display. It was caused by what turned out to be the strongest geomagnetic storm in decades and was observed around the world down to much lower latitudes than one would expect to see the lights.

On May 10, 2024 I finally had the opportunity to see an intense aurora display. It was caused by what turned out to be the strongest geomagnetic storm in decades and was observed around the world down to much lower latitudes than one would expect to see the lights.


The “What” of Auroras
The aurora borealis (northern lights) and aurora australis (southern lights) are faint visible light emissions by gases high in the atmosphere (100 km and above, up to roughly 500 km, much higher than the top of the weather-producing troposphere which is capped at 10 km). They are most often observable over a relatively narrow band of high latitudes around the globe (as described below in the “Where” section).

They are caused by complicated interactions between the far-reaching magnetic field of the Sun, the “wind” of electrically charged solar particles that travel within that magnetic field (they actually carry that magnetic field with them) throughout the Solar System, the Earth’s own magnetosphere, and the upper confines of the atmosphere (a bit more about all of this below in the “How” section).

The name of the phenomenon originates from the goddess of dawn, Aurora, who in Roman mythology, renewed herself every day, crossing the sky to announce the coming of the Sun. The word is used in modern languages, as for example in the Spanish “la aurora,” to simply mean “the dawn.” The words “borealis” and “australis” are Latin for northern and southern, respectively. Furthering the mythology connection, both in Roman and Greek mythology, Boreas is the god of the northern wind. One more thing: I prefer to use “auroras” as the plural of aurora, but you might also see “aurorae” used by some.

As far as we can tell, the first to use the aurora terminology to refer to the phenomenon was famous astronomer Galileo Galilei. In a 1619 essay about comets (which have nothing to do with auroras), he described in Italian the “boreale aurora” to refer to the dawn-like brightness that could sometimes be seen toward the northern horizon in the middle of the night (as opposed to the eastern horizon where the real dawn could be seen in the early morning). In other words, he described it as the “dawn of the north.” This means that when Galileo used the Italian word for borealis, he did not refer to the Northern Hemisphere occurrence of the lights (as opposed to those observed in the Southern Hemisphere, as it is used today). He was referring to the direction in the sky where the lights made their rare appearances in the middle latitudes where he observed them (which are in fact almost identical to the latitudes where I am writing this right now of 43.7°N, give or take a few hundredths of a degree). 

The characteristics of the aurora can vary significantly. Sometimes it is visible as upward shooting rays of various but very specific colors (see the “Auror Colors” section below), or sometimes as shifting curtains that curl or stretch in arcs across the sky. It can be straight above or only toward the horizon. It can be fainter or somewhat brighter and colorful. For most of us, most of the rare times when they appear, they are faintly visible and toward the north (a northward, dark unobstructed view needed). In the Southern Hemisphere it is the opposite; for most middle latitude dwellers, the southern lights when visible are present in the southern direction of the sky.

When too faint to trigger our eyes’ color vision (which needs 100 times more intense light than our blurrier colorless night vision), the aurora lights might look like a fog or a whiteish cloud toward the horizon. We can, however, distinguish them from those more mundane phenomena because the motions of the aurora can be very distinct, appearing and disappearing or suddenly shooting an upward ray. Additionally, stars are visible through the aurora as pinpoint white dots that would be obscured from view by clouds or fog. Modern cameras (including cell phone cameras) do pick up the colors since there is no color vision threshold needed to activate the camera sensors. They either detect the lights in color—even if in blurry fashion—or don’t detect them at all. Stars are also easier to pick up in pictures. It is, in fact, quite fun to use your smart phone as a viewer when out chasing and observing the aurora. It is also worth noting that the colors in pictures that one might see online are always more intense and saturated than they appear to the naked eye.

Also from May 10, 2004, this streak of pale green light looked like a whiteish cloud to the naked eye. This streak did move a lot and was my first clue that strong auroras were above me (this is pointing straight above). It was very exciting to see the green in the camera. You might also notice the white points as the stars that were visible through the light of the aurora.

Also from May 10, 2004, this streak of pale green light looked like a whitish cloud to the naked eye. This streak did move a lot and was my first clue that strong auroras were above me (this is pointing straight above). It was very exciting to see the green in the camera. You might also notice the white points as the stars that were visible through the light of the aurora.

The “Where” of Auroras
We already established that it is more likely to see the aurora in some high latitudes of Planet Earth, and that they make sporadic appearances in the middle latitudes (and also, it turns out, extremely rare appearances in tropical latitudes). There is a band, a sort of ring of latitudes, where they occur much more frequently (roughly 65°N to 70°N). In fact, every single day there is a range of latitudes where the aurora is actually present high above, although at any given location it might be blocked from view by clouds or even by light pollution from nearby cities. The ring expands or contracts depending on the day’s conditions. It also expands toward lower latitudes than normal as well as to a wider range of latitudes when the auroral display is more energetic. This happens when geomagnetic conditions are stronger as described below in the “How” section. Auroras additionally do not occur all the way to the poles, meaning that it is possible to be north of the lights and to have to look south to see them when at very high Northern Hemisphere latitudes (say above 70°N), and vice versa for the Southern Hemisphere.

To be more accurate, the latitudes where auroras are seen form an oval rather than a ring, slightly elongated along an imaginary line connecting solar noon and solar midnight (longitudes directly facing and directly away from the sun, respectively). This means that on any given day with favorable geomagnetic conditions when auroras can be seen, the hour or two before and/or after solar midnight is a more likely time for them to be visible. We should note that standard time midnight is a better approximation than daylight saving time midnight since it is closer to being opposite to the sun in most locations. All bets are off, however, if geomagnetic conditions suddenly increase to severe levels early in the evening or late in the night, meaning that the “around midnight” guideline does not necessarily apply to intense events. When conditions are severe enough, all it might take to spot them at a lucky middle latitude location is to be dark enough.

This oval of latitudes is additionally not centered around the geographic North and South Poles, but around the geomagnetic poles, which are not collocated with their geographic counterparts (long story, but there is a difference of several degrees in latitude). Geomagnetic poles, which result from the Earth behaving as a magnetic dipole (analogous to a bar magnet) tend to shift location at a rate of tens of kilometers per year, so they are not always in the same geographic location. Unfortunately, the point that is the center of the aurora oval (the geomagnetic north pole) is moving away from North America and toward Siberia, meaning that the high aurora activity will move farther away from the western middle latitudes in the future. Over time, therefore, the middle latitude viewings in North America during intense events will become less frequent.  

There is always an oval of auroras surrounding the geomagnetic poles of the Earth. The ones on May 10, 2024 were especially intense. They were captured by a group of NOAA/NASA polar orbiting satellites. Because of the nearer orbit (compared for example to GOES satellites that are commonly used to view our meteorological conditions), only a stripe is captured on each pass. The image here provided by NASA is a composite of images captured during an eight-hour stretch from the evening of May 10 to the morning of May 11. Notice that the North Pole is in the middle and North America is on the left side. More information can be found at https://www.nesdis.noaa.gov/news/northern-lights-over-the-north-pole

There is always an oval of auroras surrounding the geomagnetic poles of the Earth. The ones on May 10, 2024, were especially intense. They were captured by a group of NOAA/NASA polar orbiting satellites. Because of the nearer orbit (compared for example to GOES satellites that are commonly used to view our meteorological conditions), only a stripe is captured on each pass. The image here provided by NASA is a composite of images captured during an eight-hour stretch from the evening of May 10 to the morning of May 11. Notice that the North Pole is in the middle and North America is on the left side. More information can be found at https://www.nesdis.noaa.gov/news/northern-lights-over-the-north-pole

The “When” of Auroras
We already established that on any given day with moderate conditions “near solar midnight” is a more favorable time to experience auroras. Increased frequency of actual sightings as well as individual events that are strong enough to be visible at middle latitudes, on the other hand, are highly linked to the whims of our star at the center of the Solar System.

The Sun is an extremely complicated body. Like all stars, it is powered by thermonuclear fusion (its hydrogen is “burned into” helium when combined with itself under unthinkable pressures and temperatures). The “gases” inside the Sun move around in a plasma soup of positively and negatively charged hydrogen nuclei and electrons that produce magnetic fields. These are complicated irregular and constantly shifting magnetic fields close to the surface of the Sun, the photosphere. A visible sign of the Sun’s electromagnetic activity are the dark spots that can be seen in the photosphere. These sunspots have been observed and counted for hundreds of years. With time, it became apparent that there is a quite regular cycle of alternating more spots and less spots completed roughly every 11 years, suggesting that solar activity also undergoes such a cycle.

Sunspots look dark, making them easier to observe, because they are cooler than the surrounding visible solar surface—they are still, however, extremely hot—thousands of degrees. Large magnetic field loops come in and out of the solar surface at these spots, adding to the already complicated solar magnetic field. The Sun is indeed much more active when there are more sunspots, following the same cycle as the sunspots do. The peak of the cycle is what we call a solar maximum. We started counting solar cycles in the 1750s, and we are currently in Solar Cycle 25, which is currently at its peak. Back in October 2024, NASA announced that a panel of scientists had determined that solar maximum had been reached and was expected to continue for the next year or so. 

The images above are screen captures of the SWPC (Space Weather Prediction Center) solar cycle progression interactive visualization page. Since 1750, there have been 25 cycles officially numbered and as of early 2025 we are in the part of the cycle with maximum solar activity. You can play with the tool and learn more at https://www.spaceweather.gov/products/solar-cycle-progression

The images above are screen captures of the SWPC (Space Weather Prediction Center) solar cycle progression interactive visualization page. Since 1750, there have been 25 cycles officially numbered and as of early 2025 we are in the part of the cycle with maximum solar activity. You can play with the tool and learn more at https://www.spaceweather.gov/products/solar-cycle-progression

There are dramatic events, as for example massive bursts of electromagnetic radiation (solar flares), and associated ejections of solar material (coronal mass ejections, CMEs). When one of these CMEs is directed toward Earth, the much more energetic than normal particles interact with the magnetosphere, the Earth’s own magnetic field. It takes them a couple of days to arrive (give or take a day, depending on their speed), as described below in the “How” section. This is a good recipe for enhanced auroras. And so it is that during the solar maximum, the peak of each solar cycle approximately every 11 years, conditions are favorable for a higher frequency of intense aurora events that extend into lower latitudes.

It is worth repeating that auroras are always present somewhere, less intense, more intense, with more or less latitudinal extent, but always there. It might be, however, that they are not visible, as for example during the many daylight hours in the high latitude summer or during a cloudy night.

The “How” of Auroras
The explanation of exactly how those energetic solar particles coming to Earth cause the production of auroras is tricky. There is much wrong or at least too simplistic or misleading information out there. This is understandable, since there is popular demand for explanations and well-meaning but not well-informed individuals try to fit the information that they learn into their incomplete understanding. It is best to stick to authoritative sources, like for example NASA or NOAA educational sites or scientist-produced articles like this one. I am including some resource links below for those wishing to explore more. There are also a handful of excellent books about the phenomenon for those interested in learning more.

A solar wind of charged particles (negatively charged electrons and positively charged molecules that have lost their electrons) is constantly moving in the extensive magnetic field of the Sun and our magnetosphere steers most of them away from the Earth, in the process protecting us from them. Unchecked, they would infuse our atmospheric gases with so much energy that they would all eventually escape. A few, relatively speaking, are captured and move in spiraling motion along magnetic field lines toward the atmosphere. During strong solar events the ejected particles have a lot more energy than normal, accelerating the solar wind (from a background level of less than 400 km/hr to as high as over 900 km/hr), providing the conditions for middle latitude viewing.

As solar wind electrons rain downward in spiral motion along magnetic field lines into the upper atmosphere, they interact with the gases that populate those heights. Lone atoms of oxygen (as opposed to the common two-atom molecules that we breathe in the troposphere) collide with these electrons, gaining energy that brings some of its own electrons to higher energy levels than their preferred ground state. That energy is shed in the form of light when the electrons go back down in energy level. The wavelength of the emitted light is very specifically associated with a certain amount of energy, which is why only certain colors are possible, as described below in the “Colors” section.

The Earth’s magnetic field, the magnetosphere (which is not actually spherical), is produced by moving electrical charges in the liquid portion of its core. We learn in middle school that it has the same shape as that of a bar magnet. This analogy, however, does not hold when one zooms out. The pressure caused by the solar magnetic field brought on by the solar wind causes it to take a sort of aerodynamic shape, squished on the side that faces the Sun and elongated into a tail that is tens of thousands of kilometers long on the opposite side. The image was provided by NASA at https://www.nasa.gov/image-article/earths-magnetosphere-3/

The Earth’s magnetic field, the magnetosphere (which is not actually spherical), is produced by moving electrical charges in the liquid portion of its core. We learn in middle school that it has the same shape as that of a bar magnet. This analogy, however, does not hold when one zooms out. The pressure caused by the solar magnetic field brought on by the solar wind causes it to take a sort of aerodynamic shape, squished on the side that faces the Sun and elongated into a tail that is tens of thousands of kilometers long on the opposite side. The image was provided by NASA at https://www.nasa.gov/image-article/earths-magnetosphere-3/

The explanation above is extremely simplistic as there is much more that should be considered. For example, the arriving particles are on the daytime side of the Earth, not where we can observe the auroras even though they are there. The magnetic pressure as the Earth and the Sun’s magnetic fields interact causes the field lines to snap and wrap around the tail of the magnetosphere, taking captured particles with them. There, with infused energy provided by the snapped lines, the particles come down on the nighttime side of the Earth, where they interact with the atmospheric gases as described above.

The solar magnetic field and the Earth’s magnetic field lines snap open under the pressure they exert on each other in the red box to the left, allowing some of the particles in the solar wind to be steered toward the upper atmosphere where they cause the daytime aurora (not visible to us since it is on the daytime side), the open field lines fold around onto the tail of the magnetosphere recombining within the red box on the right, where infused with additional energy, more particles are steered toward the nighttime side of the Earth, producing the auroras that we can see. The image was provided by NOAA’s Space Weather Prediction Center at https://www.swpc.noaa.gov/content/aurora-tutorial


The solar magnetic field and the Earth’s magnetic field lines snap open under the pressure they exert on each other in the red box to the left, allowing some of the particles in the solar wind to be steered toward the upper atmosphere where they cause the daytime aurora (not visible to us since it is on the daytime side), the open field lines fold around onto the tail of the magnetosphere recombining within the red box on the right, where infused with additional energy, more particles are steered toward the nighttime side of the Earth, producing the auroras that we can see. The image was provided by NOAA’s Space Weather Prediction Center at https://www.swpc.noaa.gov/content/aurora-tutorial

Aurora Colors
One of my favorite topics to learn about and explain is the reason for the colors of the northern lights. Aurora green, the most abundant especially during day-to-day auroras, is very specific; it has a wavelength of exactly 557.7 nanometers, and corresponds to the shedding of energy off oxygen atoms as their electrons come down from an excited energy state to a lower but still excited energy state in a transition that can only happen in the low gas densities of the upper atmosphere above 100 km. At lower altitudes the extra energy from an excited oxygen atom is lost to collisions with other atoms and molecules. The excited atom needs to be undisturbed for approximately half a second (0.7 s to be exact), an eternity for molecular collision standards which normally happen instantaneously, and why this light shedding can only happen above 100 km. At these heights, atomic oxygen has also become more plentiful than below, which is dominated by nitrogen and oxygen molecules (with two atoms bound together) that we all learn in middle school make up the atmosphere. Even higher above, oxygen atoms can also shed red light of 630.0 and a bit of 636.4 nanometers. These are lower energy transitions but need a ridiculous 110 seconds to happen—which is trillions of times longer than instantaneous emissions—and which is why the red emissions need the even lower air densities around 200 km. This is why green auroras are sometimes accompanied by faint red above. Red-only auroras can occur when the incoming electrons do not have enough energy to excite atoms for a green emission. They do still need the lower air density higher above.

Excited molecular nitrogen (both ionized and non-ionized) provides a mix of reds and blues when going back down to a lower energy state or when recapturing electrons to become neutral again, but it takes a lot more energy to excite it in the first place. Electrons with more energy can penetrate to lower heights, say 85 km. The nitrogen-related emissions are various wavelengths of blue and red. Depending on which dominate on any given day, a reddish or purplish magenta can sometimes appear right under the green during strong aurora events. These emissions happen instantaneously as opposed to the delayed oxygen ones described above. For moving auroras, this can cause a visual effect of the green chasing the magenta. Even more rarely, ionized nitrogen molecules produce enough emissions even higher above, providing a blue and sometimes violet overlay to the reds and greens below during the most energetic aurora events.

There is of course a lot more to physical mechanisms that produce the colors of the aurora, but this should amount to enough of a satisfying treatment. With this knowledge, it becomes easy to spot fake-colored aurora photos sometimes posted by overenthusiastic individuals.

Upper atmospheric gases at different altitudes, when excited by collisions with energetic solar wind particles that enter the atmosphere or with gases that have been infused with energy by such particles, emit light of specific wavelengths when shedding the extra energy. This diagram, which has a tendency to show up on social media during aurora events, does a good job at showing which gases at which altitudes emit which colors. It is, however, missing the possibility of blues and violets way above the oxygen reds as described in the text. The image was obtained from https://auroraborealisobservatory.com/2020/11/24/have-you-ever-seen-blue-aurora-borealis/
Upper atmospheric gases at different altitudes, when excited by collisions with energetic solar wind particles that enter the atmosphere or with gases that have been infused with energy by such particles, emit light of specific wavelengths when shedding the extra energy. This diagram, which has a tendency to show up on social media during aurora events, does a good job at showing which gases at which altitudes emit which colors. It is, however, missing the possibility of blues and violets way above the oxygen reds as described in the text. The image was obtained from https://auroraborealisobservatory.com/2020/11/24/have-you-ever-seen-blue-aurora-borealis/

Monitoring and Forecasting Space Weather
Geomagnetic storms and aurora events are the realm of space weather, which deals with the conditions of the space environment from the surface of the Sun to the surface of the Earth, including the solar events, solar wind, behavior of magnetic fields, and the aurora, among others. Space weather forecasting is generally trickier than regular weather forecasting. Large events caused by Earth-directed CMEs associated with active sunspot events do give a lead time of one or two days and a better chance for models to get a handle on them, but the timing and the intensity of any anticipated geomagnetic storm might be somewhat off in either direction. At the other end of the spectrum, on any given day, sudden fluctuations of the order of hours or minutes are not normally anticipated. Many of these have to do with internal magnetosphere processes.

The best way for us regular people to keep an educated eye on the possibility of auroras is the forecasted K-index. The K-index (more accurately, the Planetary K-index) quantifies the disturbance in the Earth’s magnetic field, in a scale from 0 to 9, with higher numbers indicating greater geomagnetic activity. The local K-index is calculated based on the maximum magnetic fluctuations during a three-hour interval and the Planetary K-index (sometimes expressed as the Kp index) is calculated as an adjusted average of indices obtained from a network of official geomagnetic observatories around the world. The index is directly related to the magnitude of geomagnetic storms, with indexes of 5 through 9 corresponding to G1 through G5 geomagnetic storms, respectively. NOAA’s Space Weather Prediction Center (SWPC), which oversees the monitoring and predicting of space weather, provides a variety of useful products, such as Planetary K-index bar graphs, and three hourly text forecasts for the next three days. They also provide forecast discussions and daily reports.

There are a variety of space weather scales. The Geomagnetic Storm Scale, which can be directly correlated with K indices from 5 to 9, is relevant to the intensity of aurora events and the ability of middle latitude observers to see them. It is also related to the possibility of other disruptions, such electric grids and GPS navigation. Learn more from the Space Weather Prediction Center at https://www.swpc.noaa.gov/noaa-scales-explanation

There are a variety of space weather scales. The Geomagnetic Storm Scale, which can be directly correlated with K indices from 5 to 9, is relevant to the intensity of aurora events and the ability of middle latitude observers to see them. It is also related to the possibility of other disruptions, such electric grids and GPS navigation. Learn more from the Space Weather Prediction Center at https://www.swpc.noaa.gov/noaa-scales-explanation

Serendipitous Aurora Chasing
The three-day forecast leading to May 10, 2024, was showing promising K index numbers after a series of intense solar flares and associated Earth-directed CMEs occurred. On that day, during the middle of the afternoon, the K index suddenly increased, and quickly reached above 8 a little too early in the day, while it was still bright outside. This normally means that Europe will get a good show, and we will not, as conditions would normally not stay as intense for too long. 

As the day progressed, I kept watching the numbers and continued getting notification after notification from the SWPC. For hours, the K index stayed pegged at “8, 9–“ with values up to 8.67—the K index actually hit 9 at one point, but I only noticed that afterward. I started to be hopeful that it would last. When it became what seemed like dark enough, we still could not see anything when watching together with a group of friends at the University after a pre-graduation dinner—this was the night before undergraduate commencement ceremonies. I made it home and agreed to accompany the husband to feed a friend’s dogs. There was nothing to see (yet?) anyway, but during the drive I started noticing the strange glow all around us.

I stayed outside while he fed the dogs and looked up. We were completely surrounded by trees. Forget about an unobstructed northward view, but I kept looking. Then, a white stripe showed up along the opening between the trees right above. It could have been a cloud, but it moved! I pointed the cell phone camera toward it and could see that it was pale green! The picture above in the “What” section was during that time. After that we drove to one of our favorite dark spots to observe astronomical phenomena and we were not disappointed. It was amazing! The colors with the naked eye looked faint but ethereal. Through the cell phone however, they looked bright, green with uneven patches of magenta and red, and at some point, violet. A north view was not needed. The lights covered the entire sky. Pointing the camera up right above us and seeing a “corona” pattern with rays right on the zenith was surreal. It was especially fun to point the camera toward the south and still see the lights. There were pillars in all directions. I took so many pictures that it took me some time to sort through them afterward. The one above in the introductory section is a good example of the colors that were visible during what seemed like the peak of the event during our viewing. Other pictures are below. The show lasted for a couple of hours before clouds started to come in. By then, rather than pillars it appeared that the sky was a smooth purple/magenta or maybe violet; it’s hard to say. 

All photos above were taken during the evening of May 10, 2024: a quick shot out the window from the car, a shot straight up with the aurora right above (which can only happen for our latitudes with the strongest events, a shot toward the horizon showing not just the aurora green and red/magentas, but also a streak of violet (also only possible with the strongest events), and finally, a smooth coverage of magenta/violet before the clouds set in.

On October 10, 2024, I was attending meetings of the board of Trustees of UCAR (the University Corporation for Atmospheric Research) in Boulder, CO. This time I wasn’t anticipating the possibility of auroras as I had been in May, and when I started noticing the usual email notifications, I internally lamented that I was not home to see them, plus it was still light outside. I came back from a dinner with other trustees and decided to just in case figure out which way was north, took a picture and there WAS a greenish glow in the sky that was not visible to my eyes. I went back to my hotel room right away but when I saw that the K index was above 8, I just had to check if anything more interesting was visible.

Against my better judgement, I went back out on my own to a nearby urban walking trail, and it was very, very dark. I called the husband and talked to him the entire time I was out in the dark as if that would keep me safe. After a few minutes as I turned a corner, suddenly I could see actual color with my eyes, a patch of reddish magenta. The phone camera was picking up pillars and patches in all directions. It turns out that back at home in New Hampshire it became cloudy very quickly after the colors first showed up, so I was actually better located even though I was three degrees further south. Just like I did in May, I took way too many pictures.

The northern lights on October 10, 2024 had a lot of intense red light that was even visible with the naked eye (but much brighter as see with a camera). Red auroras are due to large numbers of incoming electrons (that interact with the oxygen in the upper atmosphere, but that do not have enough energy to excite the atom to the levels needed for the green emissions.

The northern lights on October 10, 2024, had a lot of intense red light that was even visible with the naked eye (but much brighter as see with a camera). Red auroras are due to large numbers of incoming electrons (that interact with the oxygen in the upper atmosphere, but that do not have enough energy to excite the atom to the levels needed for the green emissions.

On both of those occasions it was a thrill to see that friends from near and far had also experienced the aurora, except for the unlucky ones under cloudy skies. I can’t help philosophizing about how social media and cell phone cameras now allow for these experiences formerly reserved for select lucky ones to be instead shared among so many. 

I would still like to go out of my way to visit a faraway winter wonderland where casual gentle green auroras are a daily treat, but I am most definitely satisfied to have experienced the thrill of a severe geomagnetic event causing colorful active full-sky auroras in the middle latitudes. I might just be getting greedy, but I am hoping that with the solar maximum lasting through 2025, there will be a handful more opportunities to see the aurora under cloudless nighttime skies… with fingers crossed for nighttime timing and clear skies on those days.

Resources:

SPPC Tips on viewing the aurora
https://www.swpc.noaa.gov/content/tips-viewing-aurora

SWPC Aurora Dashboard
https://www.swpc.noaa.gov/communities/aurora-dashboard-experimental

Alaska Geophysical Institute: 
(Aurora Forecast, live cameras, viewing information)
https://www.gi.alaska.edu/monitors/aurora-forecast

SpaceWeather.com
https://spaceweather.com

Hp index site
(similar to the Kp index, but refreshes every thirty or sixty minutes, Hp30 or Hp60, as opposed to the three hours used to calculate the Kp)
https://kp.gfz-potsdam.de/en/hp30-hp60

NASA: Guide to Finding and Photographing Auroras
https://science.nasa.gov/feature/nasas-guide-to-finding-and-photographing-auroras/

NASA: Explore Auroras – Educational Pamphlet
https://gms.gsfc.nasa.gov/vis/a000000/a004900/a004934/Aurora_Infographic_Skinny.pdf

NASA news:
Solar Cycle 25 Exceeding Predictions

https://blogs.nasa.gov/solarcycle25/2022/07/27/solar-cycle-25-is-exceeding-predictions-and-showing-why-we-need-the-gdc-mission/

Solar Maximum Reached
https://science.nasa.gov/science-research/heliophysics/nasa-noaa-sun-reaches-maximum-phase-in-11-year-solar-cycle/

Wikipedia summary of the May 2024 solar storms
https://en.m.wikipedia.org/wiki/May_2024_solar_storms

Books for a general audience:
The first and most up to date book resource that explores the science and history of the aurora at a suitable level is British astronomer and science writer, Tom Kerss’ Northern Lights: The Definitive Guide to Auroras (2021), a concise and informative book that also gives detailed advice on planning for, observing, and photographing the phenomenon. British plasma physicist and science communicator, Melanie Windridge’s Aurora: In Search of the Northern Lights (2016), provides a wonderful account, using her travels as a scientist studying the aurora as a framework to cover, not only the local stories related to the phenomenon for each of the places she uses as signposts, but also the various aspects of the associated science and history of the science. Japanese American Syun-Ichi, (founding director of the International Arctic Research Center of the University of Alaska Fairbanks) Akasofu’s The Northern Lights: Secrets of the Aurora Borealis (2009), is a concise and accessible piece that focuses on describing the phenomenon as well as explaining its science using electrical generator metaphors.