Exploring the Enigmatic Northern Lights - with Sævar Helgi Bragason

Recently, there has been intense northern lights activity, described as the strongest geomagnetic storm in 21 years, impacting Earth's magnetic field. I had a captivating conversation with Sævar Helgi Bragason, a distinguished science educator and author. We delved into the implications of this surge in aurora activity and decode the secrets behind the strongest geomagnetic storm in ages. Sævar, known for his expertise in geology and astronomy and frequent appearances on radio and prime time TV, enlightens us on the science behind the northern lights, their varying colors, and the optimal times to witness these celestial displays in 2024. Moreover, he explored the upcoming celestial events, including the partial lunar eclipse and total solar eclipse in 2026, uncovering their significance and visibility.

• What's behind the recent surge in northern lights activity, including what you stated in a recent post, the strongest geomagnetic storm in 21 years? And what does this mean for Earth's magnetic field and space weather?

We are near the peak of the 11 year solar cycle when active sunspots are abundant. These active areas sometimes cause large explosions that eject charged solar particles into space. If these particles hit Earth and interact with our magnetic field, strong aurora displays happen. On May 10, 2024, we were hit by multiple clouds of solar particles almost simultaneously. These clouds were travelling so fast that they shook and rattled Earth’s magnetic field causing an extreme geomagnetic storm, the strongest one since October/November 2003. The Kp-index that measures magnetic disturbance reached its peak value of 9. Now this caused the aurora oval, under which Iceland is almost always, to expanded and reach lower latitudes. The storm was so extreme it caused Northern Lights to be seen from Mexico, Iran and India and southern lights in the Chilean Atacama desert, places where aurora hasn’t been seen in decades!

The storm has since subsided but as one can see in images the Sun is obviously quite active, pockmarked with active sunspots. We can expect more powerful geomagnetic storms in the upcoming months and years. Interestingly, the best aurora years are not during maximum but couple of years afterwards. That means the 2026-2028 or so should bring fantastic aurora frequently.

• Can you explain in simple terms what the northern lights, or aurora borealis, are, and what causes them?

The Northern Lights are formed when charged solar particles, mostly electrons, rain down on Earth’s upper atmosphere, ionising oxygen and nitrogen atoms and molecules which then give away light, the Northern Lights. The solar particles shake up Earth’s magnetic field and, on the Earth's night side, get accelerated and funnelled down towards the polar regions. That’s why we see Northern Lights close to the Arctic. This is also how the aurora oval forms. Key things to look for when chasing Northern Lights is space weather, that is, the speed and density of the solar wind and the strength and the orientation of its magnetic field. For aurora storms to occur, we need fast moving solar wind that is magnetised south. These important parameters can be seen on https://icelandatnight.is/

• Why do the colors of the aurora vary from green/white/pinkish to red/pink? Depending on location?

The colours of the aurora depend on which atoms and molecules are ionised and at what altitude. The most commonly seen yellow-green or silvery green aurora occurs at roughly 100 km altitude where oxygen molecules are ionised. Below, at roughly 80 km altitude, nitrogen molecules radiate violet or bluish light. The uppermost part of the aurora, at roughly 200-400 km altitude, atomic oxygen gives away red colour. Sometimes, the colours mix up a bit and you have shades of pink at low altitudes, even white when they get really bright.

Now at night, our eyes are virtually colour blind unless the light source is bright. Auroras are often rather faint and therefore would appear pale green or greyish to the unaided eye. When an aurora storm occurs however, they get much brighter and the colours become very obvious to the human eye. Our eyes are also much more sensitive to the green light, not so much the faint red light, which makes the green much more common to the unaided eye.

Since the colours depend on height, the red uppermost part of the Northern Lights can sometimes be seen from lower latitudes, especially so when the activity is high, like happened on May 10th. This is why the aurora appeared to be red/pink from low latitudes - people were only seeing the top of the auroras. Since these colours are hard to detect and faint, the naked eye did not perceive the colours are vividly as in the images. Cameras are more sensitive and collect the light longer.

• When is the best chance in 2024 to see the northern lights?

Observations show that on average, the likeliest months to see the Northern Lights is around the equinoxes, March/April and September/October. However, it depends on how active the Sun is. Other months give great Northern Lights too!

Since the Sun is showing signs of high activity, the outlook for the upcoming months is great! When we finally have enough darkness in the middle of August, we should start to see wonderful aurora activity again in Iceland. Next winter is very promising. From Iceland, you can more easily see dynamic and colourful aurora if the Sun cooperates.

Just be sure to check latest space weather forecast and cloud cover forecast at www.icelandatnight.is - my new website currently being developed.

• Bonus question if your dare : ) Does geomagnetic storms affect us humans? - We have been a bit tired at the office this week.

Fortunately, we have a magnetic field that protects life on Earth from raging solar storms. Geomagnetic storms however affect the Earth in multiple ways. It can induce currents that can lead to power outages. These storms interfere with the ionosphere causing radio blackouts and less reliable GPS signals. It also affects flight and increases space radiation dosage that people onboard experience even though they feel nothing. It definitely has a mental effect. By that I mean people find the visible impact of a severe geomagnetic storm exceptionally beautiful to witness.

• Could you briefly discuss the upcoming partial lunar eclipse and total solar eclipse in 2026, including where they'll be visible and why they're significant?

On the night before Friday September 18 this year, a partial lunar eclipse will be visible from Iceland, as well as in Europe, America and Africa. When this lovely little eclipse is at maximum at 02:44 UT, only about 9% of the Moon’s disc will be partially eclipsed. It’s a very shallow eclipse and will look like someone took a small bite out of the upper (northern) part of the Moon. Weather permitting, the whole eclipse will be visible from Iceland. Absolutely worth watching.

The total eclipse of August 12, 2026 is very, very exciting. It’s the first total solar eclipse to be visible from Iceland since 1954. The Moon’s umbral shadow crosses the westernmost part of Iceland, through the Westfjords, Snæfellsnes peninsula and the Reykjanes peninsula. Reykjavík is also within the path of totality for the first time since 1433! Icelanders won’t have another one until 2196! So literally a once in a lifetime experience for almost everyone alive today.

A total solar eclipse is the most awe inspiring and beautiful spectacle in nature. i chase total solar eclipses and have seen four so far. It’s unbelievably beautiful. Nothing comes close. I’ve already started preparations and opened eclipse2026.is on my 40 year birthday on April 17.

• Finally, how can we remove the clouds?

We’ll try our best to remove the clouds. :) A cloudy total solar eclipse is much more interesting than a 99,9% partial eclipse. Total solar eclipses is a wonderful opportunity to visit new places. Just make sure you stay a few days more afterwards to catch the early beginning of the aurora season.