If you ever get a chance to visit Svalbard in Norway or the Arctic region in Alaska, then keep an eye on the sky from the moment the sun goes down because if you won’t, there is a chance you might miss the most beautiful night of your life. Svalbard and the Arctic are among the few places on Earth where you can see the northern lights, a mesmerizing natural phenomenon that leads to colorful dancing waves in the sky.
Northern lights, also called aurora borealis, are polar lights observed in the northern hemisphere. In contrast, the polar lights that appear in the southern hemisphere are known as aurora australis or southern lights. Both of these phenomena are collectively called aurora, and interestingly, they are born on the surface of the Sun.
The birth of the aurora
Solar storms on the Sun's surface emit huge clouds of electrically charged particles. These charged particles are blown towards the earth by the solar wind. These particles are largely deflected by the earth's magnetic field. However, some are captured by the magnetic field and accelerated down towards the north and south poles, entering the atmosphere and colliding with gas particles. These collisions excite atoms located in Earth’s upper atmosphere, leading to the emission of light.
Lights emerge in different wavelengths depending on where the collisions occur and what molecules are involved. For instance, when a charged particle hits a nitrogen molecule, blue or purple light may appear, if it strikes an oxygen molecule located around 60 miles up, a yellow-green light is produced, but at a height of 200 miles, striking oxygen will produce a rarer red light.
These dazzling light waves are the aurora, and the color of an aurora depends on the chemical composition of our planet’s atmosphere. The discharge of coronal mass from the Sun is continuous but does not always take place with the same intensity. Sometimes the CME takes place in the form of a "storm" and a high amount of energy is released. During such coronal discharge, the brightest aurora borealis are observed.
According to the National Oceanic and Atmospheric Administration (NOAA), a strong CME storm hits Earth roughly every 11 years, and this event of fierce solar activity is called the solar maximum. The next solar maximum will occur in 2025.
Interesting facts about the northern lights
Auroras usually occur in the aurora oval, a ring-shaped belt about 4,000 km (2,500 miles) in diameter near the magnetic poles of the Earth. Because this belt is asymmetric and expands and contracts somewhat, the area where the auroras can be viewed does change. The northern lights are more likely to be visible in high northern latitudes, and can often be seen in northwestern Canada, Russia, Iceland, some places in the USA, Greenland, Sweden, Finnish Lapland, and Norway. However, they have been seen as far south as New Orleans in the western hemisphere.
In the southern hemisphere, the auroral oval is mostly over the oceans around Antarctica and the southern Indian Ocean, but they sometimes reach the far edges of New Zealand, Chile, and Australia, and occasionally even Argentina and South Africa.
Here are some more interesting facts about the northern lights:
- Venus doesn’t have a magnetic field but astronomers once spotted an aurora-like event on the planet. Scientists believe that the aurora may have occurred due to the collision between carbon dioxide and oxygen in Venus’ atmosphere and solar wind particles that penetrated deep into the upper atmosphere.
- In 1619, Italian astronomer Galileo Galilei used the term “aurora borealis” for describing the northern lights. He named the phenomenon after Aurora, the Roman goddess of sunrise, and Boreas, the god of north wind in Greek mythology. Some historians also credit French philosopher Pierre Gassendi for coining the scientific name of the northern lights.
- Magnetic midnight, the time when the North or South magnetic pole is directly between the sun and an observer on Earth, is considered the best time for watching the auroras.
- There has been a persistent myth in Alaska and some other places that Japanese people believe that a child conceived under an aurora will grow up to be strong, intelligent, rich, and good-looking. This, however, is completely untrue - Japanese people do not believe this and never have. They do travel in large numbers to see the aurora in Alaska and elsewhere, but this is for their beauty and natural wonder.
- The Inuit people (indigenous population of the Arctic and subarctic regions of Greenland, Canada, and Alaska) have legends about the northern lights that they are actually spirits of dead people playing football in the sky with walrus skulls, or walruses playing ball with a human head. Some Viking legends stated the aurora was the reflections of the Valkyries’ armor as they led fallen warriors to Valhalla, or the breath of brave soldiers who died in combat.
- Yellowknife in Canada and Tromso in Norway are sometimes called aurora capitals because these cities offer some of the most frequent sitings of the northern lights. Other places where aurora appears frequently include Reykjavik, Iceland, and the Shetland Islands in Scotland.
- If you look forward to spotting aurora borealis, you need to be very patient, because there is no fixed time at which aurora appears in the sky. However, experts believe that although they can occur anytime between 4 PM to 6 AM, the best time is usually between 10 PM to 1 AM.
- The International Space Station (ISS) is located at the same height at which some auroras occur, and is higher than others. Therefore, the ISS crew can enjoy both a side view and a view from above of the northern lights.
- The strongest CME storm was recorded during late August and early September in 1859. It led to the occurrence of very strong northern light phenomena and was referred to as the “Great Geomagnetic storm” of the "Carrington Event". The brightest aurora ever seen by astronomers was in 2015 when astronomers witnessed green and yellow aurora one million times brighter than the northern lights above a brown dwarf star located 18 light-years away.
- The Earth’s magnetic field extends tens of thousands of miles into space. It is estimated to be at least 3.5 billion years old and protects Earth from solar wind. It is generated by the movement of the molten iron in the Earth's core.
- Aurora borealis is also believed to be able to produce very faint audio effects like crackling, clapping, and wishing. The cultures of the indigenous Sami peoples of Finland, Sweden, and Norway contain myths mentioning noises when the aurora occurs.
- Apart from Venus and Earth, scientists have observed aurora on other planets, including Jupiter, Neptune, Saturn, and Uranus.
- Since the northern lights have maximum visibility during heavy solar storms., it is possible, although rare, to see the aurora as far south as Texas or Louisiana if a strong solar storm hits the Earth’s ionosphere.
- The most common aurora color is green or greenish-yellow. This is because most solar particles collide with our atmosphere at an altitude of around 60 to 150 miles, where there are high concentrations of oxygen. The second most common aurora colors are pink and red. Our eyes can not easily spot the blue and purple color northern lights in the sky.
- Many tour companies in Finland and Norway have built igloos and ice-themed hotels near the aurora sites to do the best business out of these naturally occurring polar lights.
- In Norway, you need not go to a remote location to observe the northern lights because these can be easily spotted even in the skyline above cities like Tromsø, Narvik, and Bodø.
- In Sweden, the northern lights are traditionally considered the symbol of good luck and a great fishing season. During the Viking age, some Swedish communities believed that auroras were gifts from the gods.
- In Italy, France, and Britain, myths, and legends often painted the auroras as a sign of the arrival of unfortunate events such as war, plague, conflict, and death. This may be because, when the aurora appears further south in Europe, the lights often take on the reddish hue of blood.
- The dancing waves of the aurora may feel like they are right above your head but in reality, the lights occur at heights from 80 kilometers (50 miles) to 640 kilometers (400 miles) above the earth's surface.
- If you look forward to having the brightest and clearest view of aurora borealis, the closer you are to the north side of the Earth, the better. This is why the Arctic is considered the perfect place for observing the northern lights. You may get to see the aurora even during the afternoon in the Arctic.
- In some parts of Alaska and Greenland, aurora borealis mostly appear at night time throughout the year, although they are harder to see under the Midnight Sun.
- Since the south pole is colder than the north pole, the former is neither as accessible nor as hospitable to humans as compared to the latter. So it’s much more difficult for people to travel to the south pole to watch the aurora australis. The Southern Lights also often occur over the middle of the ocean, making them less accessible. This is why the northern lights are more popular than the southern lights. However, both polar lights provide viewers with almost the same visual treat.
- The occurrence of aurora in China is very rare, due to the country’s latitudinal location but some ancient Chinese folk tales do mention them. In these legends, the aurora was believed to be a light effect resulting from the fight between good dragons and evil dragons.
- Full moon days are not considered ideal for watching aurora, due to the brightness of the night sky.
- Aurora can appear at any time of the day, but our eyes need a dark background to detect the colorful lights.
- On January 5, 1892, German astronomer Otto Rudolf Martin Brendel captured the first photo of the northern lights. This black and white photograph came out for the first time in the October 1897 issue of The Century magazine.
- The earliest depiction of the northern lights may have been in Cro-Magnon man-era cave paintings discovered in France. The cave paintings are believed to have been created around 30,000 BC and contain swirling lines which may depict auroras.
- During the Great Geomagnetic Storm of 1859, the telegraph system in Europe and North America stopped working. It is believed that if a storm of similar magnitude strikes the Earth today, it could disrupt the global communication services.
- The first pictures of aurora on a different planet (Jupiter and Saturn) were taken by NASA’s Voyager 1 and 2 space probes.
- The Space Weather Prediction Center under NOAA maintains an online aurora forecast map through which you can find out which place is better suited to see the aurora on any given day.
- In the early 1900s, Norwegian mathematician Carl Størmer studied 12,000 aurora pictures to determine the height at which auroral emissions occur. He calculated that most northern lights are produced at between 56 miles and 600 miles above the Earth's surface.
Despite so much advancement in astronomy and atmospheric sciences, there are still questions about the science that governs the auroras and the CME. However, that does not mean scientists are not looking into it. NASA’s Parker Solar Probe, which flew through the Sun’s upper atmosphere in December 2021, is currently collecting vital information about CME.
Therefore, it is very likely that in the coming years we will have even more detailed information about the eye-catching auroras that appear in our skyline.