NEWS In northern Sweden, we are currently experiencing a solar maximum. But what are Northern Lights, what is the best time to see them, and can you really hear them? Patrik Norqvist, a doctor of astrophysics at Umeå University, explains. “This is a particularly good time to see Northern Lights, especially when it is dark and the sky is clear in the evenings,” he says.
They are nature’s fireworks with bright colours dancing across the sky. For both young and old, seeing the Northern Lights is a powerful experience, and many people travel long distances to Northern Europe just to see them. The light we see consists of small particles, primarily electrons, thrown off from the Sun and crashing into atoms in Earth’s upper atmosphere at high speeds.
“The phenomenon can be compared with what happens in a fluorescent tube or a neon sign. When the different shells around the atoms are hit by these electrons, light is emitted,” explains Patrik Norqvist, doctor of space physics and associate professor in physics at Umeå University.
Northern Lights over Loberget, Botsmark. But it doesn't have to be snow on the slopes or cold to be able to see the Northern Lights.
ImageFredrik Larsson / Visit UmeåThe colours we see in Northern Lights are result from the type of atom that the electrons hit. Some atoms, like oxygen, can emit more than one colour. Green often results from oxygen while hydrogen atoms usually emit purple or pink.
The high acceleration of electrons required to trigger Northern Lights and Southern Lights (also known as aurora borealis and aurora australis, respectively) only occurs around the Earth’s two magnetic poles in the southern and northern hemispheres. Northern Sweden is within the so called auroral zone in the northern hemisphere, allowing ample opportunities to see the Northern Lights.
“If the speed of the electrons is extremely high, the auroral zone can be pushed down into southern Sweden or in extreme cases into continental Europe. But reaching south of Sweden requires very high speeds. So Stockholm has less Northern Lights than Umeå and Umeå has less than Kiruna. When southern Sweden does see Northern Lights, however, they can be quite the show since they are the result of very strong Northern Lights,” says Patrik Norqvist.
Patrik Norqvist, doctor of space physics and associate professor in physics at Umeå University.
ImageMattias PetterssonAutumn 2024 is an unusually active period for Northern Lights since the Sun is in a particularly chaotic phase that occurs on an 11-year cycle. When this occurs, the Sun switches its polarity, which can be seen in more sun spots and instability in its magnetic field. This leads to solar storms, which can impact daily life here on Earth through electrical outages, disruptions to air travel, and Northern Lights.
Now is the optimal time to see Northern Lights
“This ebbs and flows with a periodicity that we have been able to follow for hundreds of years and seems to be very stable in its 11-year cycle. We are at the solar maximum right now, which is providing us with lots of impressive Northern Lights. Now is the optimal time to see them. They say this is the best chance to see Northern Lights in the last 23 years.”
To see Northern Lights, it needs to be dark and you need clear skies and as little light pollution as possible. So your best bet is to get away from the city centre.
Is it a myth that it has to be cold?
“In a way. It is important that it is clear, but cold weather often is associated with clear weather. The temperature doesn’t play a role though. The action up there is not impacted by whether it is -20 ° or +20 °. It needs to be dark and clear skies to see the stars. Of course, it is darker longer in the winter.”
There are now apps and websites that can forecast when Northern Lights might be visible by combining estimates of solar activity with the risk of cloud cover. These are dependable in the same way that weather apps show us the best estimate for weather conditions, explains Patrik.
An interesting aspect is that cameras tend to capture Northern Lights better than the human eye.
“It’s odd that Northern Lights are often better in pictures than when seeing them in real life. So one suggestion is to take your camera or mobile phone and take pictures even if you don’t see much.”
Northern Lights over Nydala Lake, Umeå.
ImageFredrik Larsson / Visit UmeåCan you hear Northern Lights? Probably not, explains Patrik.
"Many people say they have heard Northern Lights, even space physicists and people who I know well and have great confidence in. But as far as I know there is no evidence for hearing them, and no one has succeeded in recording any sounds, which is a strong indication that there aren’t any.”
Northern Lights occur much too far away, and it would take several minutes for the sound to reach us on the Earth’s surface. Additionally, the air is too thin to be able to convey sound waves to us. But there are other possible explanations.
“Perhaps the brain produces a sound to match what it sees? There is also a theory that Northern Lights could create electromagnetic waves that cause a crackling sound in the hair or in the hair in our ears in some way, a type of radio waves or artificial sound. But we can definitely eliminate the possibility that it would be a normal sound from the Northern Lights,” explains Patrik.
