A view of the Northern lights from Iceland. Image Credit: Joshua Earle via Unsplash
You must have come across dazzling images of the green, red and purple auroras on the internet and wondered if you could see them too. Well, we have good news for you. The next 6 months will be the best time to catch a glimpse of these dazzling auroras. This article will help you learn the science behind these magical lights.
What is aurora, and how does is form
The magnetic field of our planet shields us from solar particles that can strike Earth’s upper atmosphere at up to 45 million mph (72 million kph), which is how the northern lights are produced. The solar wind is produced by charged particles that the sun is constantly expelling from its corona, or upper atmosphere. The aurora is created when the solar wind strikes Earth’s ionosphere or high atmosphere. The phenomenon is known as the northern lights (aurora borealis) in the northern hemisphere and the southern lights (aurora australis) in the southern hemisphere.
The colours of the aurora depend on the interacting atoms or molecules in the Earth’s upper atmosphere. Here is a list of colours that auroras can produce:
Green: It is the most common colour observed from the ground produced by oxygen molecules.
Pink and dark red: These colours are produced by nitrogen molecules.
Red: Oxygen atoms are behind the red auroras.
Blue and purple: These rarer colours are caused by hydrogen and helium molecules.
Check out this video from NASA to learn more about auroras:
The sun is reaching solar maximum
The sun undergoes an 11-year solar cycle based on its activity. Solar maximum refers to the highest rate of solar activity. Larger amounts of energetic particles are released from the sun during periods of increased solar activity, such as solar flares, enhanced solar wind, and massive plasma and magnetic field expulsions known as coronal mass ejections (CMEs). Stronger aurora displays can result from geomagnetic storms, often referred to as solar storms, which are massive disruptions in Earth’s magnetosphere caused by these charged particles.
NOAA predicts that the sun will reach solar maximum any time between November 2024 and March 2026. Note that solar maximum is not a point in time, rather it is a phase that could last for months and even a year. It is also possible that we are already experiencing the solar maximum, but we won’t know for sure for 7 months, due to how the solar maximum is calculated.
The relation between solar maximum and heightened auroral activity is simple. Solar maximum means more charged particles are released from the sun. This will cause more geomagnetic storms in the Earth’s ionosphere. This not only means more frequent auroral activity, but also a stronger and more vivid display of auroras.
A comparison of solar activity during solar minimum and maximum. Image Credit: NASA
Arctic nights are coming
The period known as arctic night or polar night occurs when the Sun does not rise over the horizon for longer than twenty-four hours. It is the opposite phenomenon of the Midnight Sun. In the northern hemisphere, this happens inside the Arctic Circle, which is above 66.3 degrees North.
Starting from September, nights in the Arctic region start growing longer, and this lasts till the end of March. In December and January, almost the entire Arctic Circle reaches arctic nights, meaning no sunrises and sunsets.
Arctic nights give the best and darkest night experiences, and this is especially important if you want to see auroras. Longer nights mean better opportunities to grab a view of the auroras.
Display of Aurora on a moonlit night. Image Credit: Vincent Guth via Unsplash
Autumn and spring equinoxes
The chances of auroras taking place in Earth’s upper atmosphere are increased. This happens due to what is known as the “Russell-McPherron Effect” and the “Equinoctial Effect”. The Russell-McPherron effect shows that the north-south component of the sun’s magnetic field goes up and down over a year, and it corresponds with the wobbling of Earth’s axis. And these magnetic fluctuations are at their highest during the equinoxes.
The Equinoctial effect shows that the Earth’s magnetic poles (north and south) are at right angles to the flowing solar wind during equinoxes. This means that more charged particles interact with Earth’s ionosphere during these periods.
Earth’s orbit around the sun during equinoxes and solstices. Image Credit: NWS/NOAA
It has been statistically shown that the auroral activity increases significantly during the months of September-October and March-April.
Seasonal activity of geomagnetic storms between 1932-2007. Credit: NASA, David Hathaway
Best places to see auroras
To simply put, any place inside the Arctic Circle will give you a greater chance of seeing the dazzling aurora lights. Here are some of the more popular places you can travel to:
Finnish and Swedish Lapland
Tromso and Lofoten, Norway
Kirkjufell, Iceland
Fairbanks, Alaska
Yellowknife, Canada
Murmansk, Russia
Kangerlussuaq, Greenland
A colourful display of Northern Lights from Tromso, Norway. Image via Unsplash
Few tips for aurora watching and photography
If you are planning a trip to watch and photograph the northern lights, you should consider the following points:
Plan your trip during the new moon phase. While stronger auroras are still visible with a bright moon in the sky, you will miss out on the dimmer auroras.
Choose a place with zero or less light pollution. Light pollution can significantly affect your viewing and photographing of auroras, just like any other forms of astrophotography.
Check the local weather. A lot of places inside the Arctic Circle get heavy snowfall during the winter months. Choose a period when there are fewer chances for snowing and raining.
A fast lens, with an aperture of f/2.8, f/1.8 etc. will be your best friend for aurora photography. Stronger auroras move very fast and you won’t be able to have longer shutter speeds (unless you want fuzzy images). A fast lens will also be able to help you with making live videos of the aurora without putting too much pressure of the ISO.
Carrying a wide-field lens, 30 mm or wider, will also help you during aurora photography.
Auroras are hard to predict beforehand. You can install apps like My Aurora Forecast & Alerts to be ready when the auroras are visible from your location.
View of Aurora from Kirkjufell, Iceland. Image Credit: Alexander Milo via Unsplash
Now that you know about the glorious chances of getting a view of the northern lights, plan a trip and start packing your bags. Do not forget to pack a lot of winter clothes. Clear skies!
