The Magic of Aurora Lights: Where, When, and Why

Just a week ago, we had a fascinating display over a couple days of Aurora Borealis that most of the US was able to witness.  Let's briefly explore what they are, why the occur and when the best time to view them are.

The aurora lights, also known as the aurora borealis in the Northern Hemisphere and the aurora australis in the Southern Hemisphere, are one of nature’s most spectacular phenomena. These natural light displays have captivated humanity for centuries, inspiring countless myths, legends, and scientific inquiries. In this article, we delve into the mystical world of auroras, exploring where they are typically seen, the best times of year to view them, and the science behind their dazzling displays.

Where to See the Aurora Lights

Aurora borealis is predominantly visible in high-latitude regions around the Arctic Circle, including:

• Norway: The city of Tromsø, nestled within the Arctic Circle, is a prime location for aurora sightings.
• Sweden: Abisko National Park is renowned for its clear skies and frequent aurora activity.
• Finland: Finnish Lapland, especially around the town of Rovaniemi, offers stunning views of the northern lights.
• Iceland: Reykjavik and the surrounding countryside provide excellent vantage points for observing the aurora borealis.
• Canada: The Yukon, Northwest Territories, and northern parts of Alberta and British Columbia are great spots for aurora viewing.
• Alaska, USA: Fairbanks is a well-known destination for seeing the northern lights.

Aurora australis is less commonly observed due to its location in the remote Southern Hemisphere, but it can be seen in:

• Antarctica: The most reliable place to see the southern lights, though it's often accessible only to scientists and researchers.
• New Zealand: The southern regions, particularly around Stewart Island and Dunedin, sometimes experience aurora displays.
• Tasmania, Australia: On rare occasions, aurora australis can be seen from this southernmost state.

Best Times of Year to View Auroras

The optimal time to witness the aurora lights is during the winter months, when the nights are longest and skies are darkest. In the Northern Hemisphere, the best period spans from late September to late March. In the Southern Hemisphere, the prime time is from late March to late September. Key factors that enhance aurora visibility include:

• Darkness: The absence of light pollution and clear, dark skies are crucial. Remote areas far from city lights provide the best conditions.
• Solar Activity: Auroras are more frequent during periods of high solar activity, which follows an 11-year solar cycle. Peak solar activity leads to more intense and frequent auroral displays.

Why Auroras Occur

The aurora lights are the result of complex interactions between the Earth's magnetic field and charged particles from the sun. Here’s a simplified breakdown of the process:

1. Solar Wind: The sun emits a constant stream of charged particles known as the solar wind. During periods of high solar activity, such as solar flares or coronal mass ejections, the number of these particles increases.
2. Earth’s Magnetosphere: When these charged particles reach Earth, they are drawn towards the poles by the planet’s magnetic field, creating a region called the magnetosphere.
3. Atmospheric Interaction: As the solar particles collide with gases in Earth’s atmosphere—primarily oxygen and nitrogen—they excite these gas molecules. When the molecules return to their normal state, they release photons, which are seen as the shimmering lights of the aurora.

Different colors in the aurora are produced by different gases and altitudes. Oxygen at higher altitudes (above 150 miles) emits red light, while at lower altitudes (up to 150 miles) it produces green light. Nitrogen can give off blue or purplish-red light.