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The Aurora Borealis and Solar Storms

2024 is going to go down as an incredible bucket list year. In the span of 33 days, I have had the opportunity to view a total solar eclipse and observe the aurora borealis.  My husband and I have been trying for years to catch the aurora here in Southern New Hampshire. Weather never seems to be in our favor and Friday night, it was looking questionable with our spring New England skies.

A coronal mass ejection is a large eruption of gas from the Sun's chromosphere. During a solar maximum, on average the Sun will release 3-4 CME's a day. Not all CME's that are ejected from the Sun travel towards Earth. On May 9, 2024, several coronal mass ejections erupted from the Sun all headed towards Earth. A fast-moving CME overtook the previous slower moving eruptions and combined forming a cannibal event that ramped up the intensity of the storm hitting earth. The CMEs contain a strong embedded magnetic field that interacts with our magnetic field and ionizes gases in our atmosphere. The CME's originated from the active sunspot cluster AR3664. Sunspot AR3664 is as large or larger than the sunspot that were observed during the "Carrington Event" in 1859. AR3664 is 16 times the diameter of the Earth. If you still have your eclipse glasses from the April 8 total solar eclipse, you can grab them and view the cluster, providing the weather cooperates and the Sun is not obscured by clouds!

An X3.98 flare was released in the early morning hours of May 10, 2024. X class flares are the most powerful flares, followed by M class, B class, C-class, and A-class flares, with each subsequent class being 10 times weaker than the previous. High frequency radio blackouts were observed throughout Asia, eastern Europe and eastern Africa shortly after the X-class flare hit earth. The electromagnetic radiation released during the flare travels at the speed of light and reaches Earth approximately 8 minutes after its release. The energy ionizes the atoms in the upper atmosphere creating an atmosphere layer that is denser than normal making which makes it more difficult for radio waves to pass through. These flares are different than coronal mass ejections which travel at slower speeds. Coronal mass ejections can take several days to reach Earth.

High frequency radio blackouts were observed throughout Asia, eastern Europe and eastern Africa shortly after the X-class solar flare. (Image credit: NOAA/SWPC)

Sunspot AR3664 Image Source: NASA, Astronomy Picture of the Day 5/11/24

Originally the storm was predicted to be a G4 storm, but the cannibal event described above turned into a G5 storm on Friday, May 10, 2024 turning this into the largest storm in the past 20 years. NOAA’s Space Weather Prediction Center (SWPC) rates the strength of solar storms on a G scale from G1 to G5. The storm was the largest in over 20 years since the Halloween 2003 storm. Friday night, the Kp index reached a 9 and a display of the aurora borealis was observed as far south as Florida and Joshua Tree National Park. The threat of these geomagnetic storms will continue until the active sunspot cluster, which is roughly 16 times the diameter of Earth, rotates out of our view, this could take days.

Around 10:30 I looked out and noticed a pink hue to the sky. I immediately grabbed my tripod and started snapping the sky. Our north backyard view of the sky is obscured by trees and Mt Uncanoonuc, so we can only see from 45-90 degrees and cannot see the horizon. Our restricted sky view didn't matter, the entire sky was magenta, no matter which direction you looked. However, this restricted view did not allow me to see the greens which are typically closer to the horizon.

Auroral glow in New Boston, NH on May 10, 2024 at approximately 10:30 am, Little Dipper [Ursa Minor] in the center of the photo

The colors of the aurora that we observe are related to the photons of light emitted as atoms in our atmosphere are ionized. Our atmosphere is composed of nitrogen, oxygen, hydrogen and lesser amounts of carbon, helium, argon.

  • Red is monatomic oxygen (O) or diatomic nitrogen (N2), typically only observed under intense solar activity because oxygen is n low concentration at the higher altitudes of the atmosphere

  • Blue is ionized diatomic nitrogen (N2+)

  • Green is excited monatomic oxygen (O) at lower altitudes

  • Blue/Purple are hydrogen and helium

  • Pinks, oranges, yellows and purples come from color mixing

When my husband got home, we loaded Sid up and headed north to find a longer northern view. After several stops, we ended up at Gould Hill Apple Farm in Contoocook, NH. We arrived around 1215-1230 am and just constantly shot the sky. So much movement in the aurora as the clouds cleared.

aurora borealis and Bootes constellation
Looking north at the aurora borealis on Gould Hill in Contoocook, NH. The Bootes constellation can be seen in the upper right corner of the image. Photo by Stephanie Erickson, 5/10/24 [10second exposure]

Aurora Apps and Accounts

I used two apps for tracking the aurora. The first is My Aurora Alerts and Forecasts. This app provides real time alerts for when the Kp index rises above a specific level. The Kp needs to be above a 7 in order for me to see it in Southern New Hampshire, so my alerts are set to notify me when the Kp reaches a 7 or above. The app also has an aurora map that geolocates you and displays where the auroral oval is in relation to your location. The app also has the best locations to view the aurora now and live aurora webcams. Additionally, the app provides the potential of seeing the aurora in your location, the percentage of cloud cover and the aurora forecast over the next several days. The app also has images of the Sun under different wavelength filters so you can view the sunspots and flares from the Sun.

Available on the Apple Store and Google Play

The Second App, Aurora Forecast, provides similar information as My Aurora Alerts and Forecasts, but has some additional data that this data nerd devours. Data such as Proton Flux, Solar Wind Density, Solar Wind Speed and Solar Wind Ion Temperature. In addition to the map which the auroral oval, this app also includes the globe version with the auroral oval superimposed on it.

Available on the Apple Store

What to look for?

A glow in the sky that moves and shifts. As it brightens, colors will begin to emerge. It generally takes our eyes up to 30 minutes to adjust to the low light. Using a red-light flashlight will speed up the rate at which you can adjust to the low light and see the aurora. Our phones are able to detect much lower levels of light and color than the rods and cones in our eyes can. Our eyes can only detect color if it is bright enough, which is why itis more difficult to see at night with the absence of the Sun and Moon light than it is during the day.

iPhone Settings

Our phones are amazing, they turn everyone into a photographer. On the iPhone, change your exposure to +2.0 and the time of the exposure to 10-seconds. Here is a YouTube short I found that shows the settings.

AR3664 has now rotated out of Earth's direction, but astronomers are paying attention to another active area that has been releasing CME's and flares northwest of AR3664. We are approaching solar maximum for this current 11-year solar cycle, so the heightened activity will continue to occur. The May 10th event displayed the aurora for all 50 states to observe. Hawaii hadn't seen an aurora since the 1859 Carrington Event! Keep an eye on the sky this summer and maybe we will experience the aurora borealis again this year.

If you are an educator looking to capitalize on the aurora excitement, check out my Aurora Borealis Stations activity linked below.

Lesson Activities

Check out my activity Aurora Borealis Stations to learn more about auroras and how they are formed.


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