The Northern Lights, also known as Aurora Borealis, is a spectacular natural phenomenon that occurs in the polar regions of the Earth. It is caused by the interaction of charged particles from the Sun with the Earth's magnetic field, resulting in a stunning display of colorful lights in the night sky. The intensity and frequency of the Northern Lights are closely tied to the solar cycle, a periodic variation in the Sun's magnetic activity that lasts approximately 11 years. As we enter solar cycle 25, astronomers predict that the Northern Lights will be even more incredible than ever before. In this blog post, we will explore why this is the case.

Solar cycle 25 officially began in December 2019, and it is expected to peak in 2025. The peak of the solar cycle is characterized by a higher frequency of solar flares and coronal mass ejections (CME’s), which are bursts of energy and plasma particles that are ejected from the Sun's atmosphere. These particles travel through space and can interact with the Earth's magnetic field, producing the Northern Lights.

One of the key factors that determine the intensity of the Northern Lights is the number of sunspots on the Sun's surface. Sunspots are dark areas on the Sun that are caused by magnetic fields. During periods of high solar activity, there are more sunspots on the Sun's surface, and this is associated with a higher frequency of solar flares and coronal mass ejections. When these particles reach the Earth, they excite the atoms and molecules in the Earth's atmosphere, producing the colorful lights of the Northern Lights.

According to predictions from the National Oceanic and Atmospheric Administration (NOAA), solar cycle 25 is expected to be slightly stronger than the previous solar cycle, which was characterised by a relatively low number of sunspots. This means that we can expect to see more frequent and intense Northern Lights displays over the next few years.

In addition to the increased solar activity, there are other factors that contribute to the intensity of the Northern Lights. For example, the Earth's magnetic field plays a critical role in shaping the and placing the Northern Lights. When the Earth's magnetic field is disturbed by solar activity, it can cause the Northern Lights to move further south and become more visible from lower latitudes.

Furthermore, factors such as weather conditions, light pollution, and the time of day can also affect the visibility of the Northern Lights. Therefore, it is important to plan your Northern Lights viewing carefully, taking into account these various factors.

Aurora Mechanics

Interplanetary Magnetic Field

The interplanetary magnetic field (IMF) plays a significant role in affecting the Northern Lights. The IMF is the magnetic field that extends throughout the solar system and is carried by the solar wind, a stream of charged particles that flows from the Sun. When the solar wind interacts with the Earth's magnetic field, it can cause disturbances that lead to the Northern Lights.

The IMF has a direction, which is typically aligned with the Sun's magnetic field. However, as the solar wind flows past the Earth, the IMF can be compressed or stretched by the Earth's magnetic field, which can alter its direction. When the IMF is directed southward, it can cause a phenomenon known as magnetic reconnection, where the Earth's magnetic field lines connect with the IMF and energy is transferred to the Earth's atmosphere. This energy transfer excites the particles in the atmosphere, leading to the bright and colorful display of the Northern Lights.

In addition to its direction, the strength of the IMF also plays a role in affecting the Northern Lights. When the IMF is strong, it can compress the Earth's magnetic field, leading to a greater likelihood of magnetic reconnection and a more intense display of the Northern Lights.

Overall, the interplanetary magnetic field is a crucial factor in understanding and predicting the Northern Lights. By monitoring the direction and strength of the IMF, scientists can better predict when and where the Northern Lights will occur, and enthusiasts can plan their viewing accordingly. This is the information I pay the most attention to when planning my own northern lights trips.

BT and Bz

BT and Bz are measurements of the interplanetary magnetic field (IMF), which plays a crucial role in the occurrence and intensity of the Northern Lights.

BT refers to the total strength of the IMF, which is the measure of the strength of the magnetic field in all directions. When the IMF is strong, it can compress the Earth's magnetic field and increase the likelihood of magnetic reconnection, which can lead to a more intense display of the Northern Lights.

Bz, on the other hand, refers to the component of the IMF that is oriented in the north-south direction, also known as the vertical component. When the Bz component of the IMF is directed southward, it can cause the Earth's magnetic field to connect with the IMF, which can trigger a geomagnetic storm and lead to a bright and colorful display of the Northern Lights. In contrast, when the Bz component is directed northward, it is less likely to cause a geomagnetic storm and the Northern Lights may be less visible.

Therefore, Aurora Hunters often monitor both BT and Bz measurements to better understand and predict the occurrence and intensity of the Northern Lights. The measurements can be obtained from various space weather monitoring tools, such as the ACE spacecraft or ground-based magnetometers, and can help provide early warning for potential geomagnetic storms that could produce an impressive display of the Northern Lights.

KP

KP is a measure of geomagnetic activity that ranges from 0 to 9, with higher values indicating more intense activity. It is based on the maximum fluctuations in the horizontal component of the Earth's magnetic field observed over a three-hour interval at a given location.

While KP is a useful measure of geomagnetic activity and is often used to forecast the likelihood of Northern Lights, it is not the only factor to consider. KP only measures the horizontal component of the Earth's magnetic field, whereas the vertical component (Bz) of the interplanetary magnetic field (IMF) is also crucial in determining the occurrence and intensity of the Northern Lights.

Furthermore, the KP index is only an indicator of geomagnetic activity at a specific location and may not accurately represent activity at other locations. This is because the Earth's magnetic field is not uniform and can vary in strength and direction at different latitudes and longitudes.

Therefore, while KP is a useful tool in predicting Northern Lights activity, it should not be the sole factor considered in a Northern Lights forecast. Other factors such as solar wind speed, IMF direction and strength, and local weather conditions can all play a role in determining the likelihood and intensity of the Northern Lights.

Colours

The colours of the Northern Lights, also known as Aurora Borealis, are determined by the types of gas particles in the Earth's atmosphere that are being excited by the charged particles from the solar wind. When the charged particles collide with the gas particles in the atmosphere, they transfer energy to the gas atoms and molecules, causing them to emit light of different colours.

The most common colour of the Northern Lights is green, which is produced by the excited oxygen molecules at an altitude of about 60 miles (110km) above the Earth's surface. The excited oxygen atoms and molecules emit green light when they return to their normal state after being excited by the charged particles.

The second most common colour of the Northern Lights is red, which is produced by the excited oxygen atoms at an altitude of about 200 (340km) miles above the Earth's surface. Red light is emitted when the excited oxygen atoms return to their normal state after being excited by the charged particles.

Blue and purple colours in the Northern Lights are produced by the excited nitrogen molecules at an altitude of about 60 miles (110km) above the Earth's surface. The excited nitrogen molecules emit blue and purple light when they return to their normal state after being excited by the charged particles.

The intensity and brightness of the Northern Lights can also affect the perceived colours. For example, when the Northern Lights are faint, they may appear as a pale green or white, while during intense displays, the colours may appear more vibrant and include a range of colours. The most elusive colour is pink, but we’ll see a lot of it during the rest of this season and next season during Solar Maximum.

In summary, the colours of the Northern Lights are determined by the types of gas particles being excited by the charged particles from the solar wind, and the altitude at which the gas particles are located. Different gases emit different colours when they return to their normal state after being excited, leading to the range of colors seen in the Aurora Borealis.

My workshop

The Lofoten Islands in Norway are known for their stunning natural scenery and are a popular destination for photographers and nature lovers. The islands are located in the Arctic Circle, which makes them an excellent place to see the northern lights. The Lofoten Islands Viking Photography Workshop with Dave Williams and Kersten Luts is an exceptional opportunity for photographers to enhance their skills while exploring the stunning natural beauty and rich Viking history of the Lofoten Islands. Dave Williams is an experienced photographer and instructor who has taught photography workshops around the world. He will provide expert guidance and instruction on how to capture stunning images of the northern lights, landscapes, and cultural elements of the Lofoten Islands. Kersten Luts, a skilled photographer and guide, will also provide participants with insights and knowledge about how to photograph and work with our Viking model on location.

During the workshop, participants will have the chance to experience the unique landscape and culture of the Lofoten Islands, including fishing villages, rugged coastlines, and majestic mountains as well as chasing the northern lights at every opportunity. They will also have the opportunity to learn from Dave and Kersten in both classroom and hands-on settings, receiving personalised feedback and instruction on their photography. The workshop is designed for photographers of all skill levels, from beginners to advanced, and the small group size ensures that each participant receives individual attention and guidance. Participants will also have the opportunity to network with like-minded individuals and build lasting connections in the photography community. Overall, the Lofoten Islands Viking Photography Workshop with Dave Williams and Kersten Luts is a once-in-a-lifetime experience for photography enthusiasts looking to improve their skills while exploring the beauty and culture of one of Norway's most stunning locations.

If you’re interested in joining us, we’d like to give you 5% discount on the workshop price by using the code DAVE5 when booking.

Much love
Dave