The Northern Lights are a naturally occurring phenomenon that has captured the attention and imaginations of humans for generations. Also known as aurora borealis, the Northern Lights attract thousands of tourists to the Arctic every year to watch the night sky light up in a dizzying array of colors. While many peoples originally saw the Northern Lights in mythic or religious terms, modern science has determined that they are the result of the sun, with sunspots playing a major role in their frequency and strength.
Sunspots have a direct connection to the Northern Lights, with periods of high sunspot activity correlated with more frequent and stronger auroras and vice versa. Read on to learn how sunspots affect the Northern Lights.
Sunspots and the Northern Lights
The Northern Lights are created through the Earth’s interaction with solar wind, which is the term used for the streams of particles emitted by the sun on a constant basis. Solar wind is deflected by the magnetosphere, an invisible barrier created by the Earth’s magnetic field. In areas of the world where the magnetosphere intersects with the atmosphere (the North and South Poles), this interaction manifests in the form of auroras that can be seen with the naked eye.
Because of this, the frequency and strength of auroras is dependent on the frequency and strength of solar wind. During periods of high solar activity, more solar wind is emitted, resulting in auroras occurring more frequently and those auroras also being larger and more varied in color. Conversely, during periods of limited solar activity, auroras are rarer and smaller in size. Periods of peak solar activity are known as “solar maximums,” while periods of waning activity are known as “solar minimums.”
What role do sunspots play in this? Sunspots are dark objects that appear on the sun’s surface at irregular intervals. The sun’s magnetic field is constantly reversing, with the north pole moving to the south and vice versa, and these constant magnetic shifts lead to temperature distortions on the sun’s surface. Sunspots are formed when magnetic field fluctuations prevent heat transfer, leading to areas of the sun’s surface being cooler than the sun as a whole.
Sunspots can last anywhere from a few days to a few months before they dissipate, and they can also vary in size from as small as a few kilometers to over 160,000 kilometers in size. They also drift across the sun’s surface as magnetic field shifts constantly occur, and larger sunspots can be observed with the naked eye.
Solar wind is correlated with sunspot activity, as the temperature and magnetic disruptions that cause them lead to a feedback loop of excess particles being emitted out into space. This means that during periods of high sunspot activity, auroras occur on Earth with greater strength and frequency due to increased solar wind output. Conversely, during periods where there are few or no sunspots, auroras are smaller and occur less often.
Scientists have tracked solar activity for century and have identified cycles of low and high sunspot formation. For example, it has been observed that the sun’s magnetic poles reverse location every 11 years. During the peak of this cycle, when the poles are located near the sun’s equator, sunspot activity increases due to stronger magnetic fluctuations, leading to increased solar wind and more frequent auroras. Scientists estimate that the next peak in the solar cycle will occur around 2025.
In addition to this, there are longer periods of solar activity that have been observed. 2008 marked the end of the Modern Maximum, a period of increased sunspot activity that began in 1914, leading to warmer temperatures on Earth and high aurora activity due to solar wind. A similar period occurred during the Medieval Maximum from 1100 to 1250, the end of which created the Little Ice Age, a period in which global temperatures cooled.
Scientists have not identified the cause of these larger maximum and minimum periods or a means by which they can be predicted. However, sunspot activity has decreased markedly since 2008, leading many scientists to believe that the sun has moved into a new minimum. This means that for the foreseeable future, auroras will occur less often and will be smaller in size than those that were observed during the Modern Maximum.
Contrary to some claims online, reduced sunspot activity does not mean that the Northern Lights will disappear entirely. Even during waning periods of solar activity, sunspots still form with regularity, and the sun always gives off solar wind as a matter of course. However, it means that reduced solar wind will lead to auroras becoming less common and smaller than they were during the Modern Maximum.
Sunspots are a natural occurrence and have major effects on the Earth’s habitability and climate. In particular, sunspots exert a heavy influence on the Northern Lights due to how they affect the amount of solar wind that is discharged into the Earth’s magnetosphere. However, because the Northern Lights will always occur regardless of sunspot activity, you shouldn’t let this factor influence your decision to take a trip to the Arctic. If you’re curious about seeing the Northern Lights, book a trip and prepare to have the experience of a lifetime.