FAQ

Can you see the Northern Lights in Sweden?

The northern lights, or aurora borealis, appear around the middle of August to around the end of March all over Sweden... But for the very best chance of seeing the northern lights you should make the trip to Torneträsk area in Abisko. If you are in the lower latitude's near and around 60° you preferably need Solar Flares on the sun or Solar Wind.

Can you see the Northern Lights in Stockholm?

Yes! As you can see on this page! Usually, the northern lights are only visible in Sweden's northern reaches... It is possible to see the northern lights much further south than Jokkmokk, however, and during periods of particularly high solar activity, it's not unheard of to see the aurora as far south as Stockholm and Gothenburg and even the northern parts of the United Kingdom...

When can I see the lights?

From middle of August to March. Anywhere from 21:00 ot Sunrise (9pm to Sunrise). (Swedish local time)

When is the best time to see the northern lights?

The darkest period which is between November and February offer longer evenings for gazing at the sky, while the strongest lights normally occur during October and March between 9pm and 1am. They are also seen as early as late August and as late as mid April.

The phases of the moon don’t affect aurora activity, but the moonlight can reduce the intensity of the displays. It is often mentioned that full moon should be avoided due to higher light concentration, however it is one of the most magical experiences to see the full moon together with the northern lights dancing across the sky. During a new moon the sky is slightly darker, but it is very much a matter of personal opinion, which of these sightings is the best.

 

Where do you go to see the Northern Lights?

"Northern Lights zone" — Go above 60° latitude, to 72°. A significant portion of Sweden lies within the zone (called the 'auroral oval'). Ideal viewing conditions are crisp, cold, clear, and cloudless skies. But for the very best viewing conditions you should make the trip to Torneträsk (a micro climate area) in Abisko.
LaplandTrip.com can arrange everything you need!

How does the Northern Lights work?

Solar particles collide with atmospheric gases and create colorful curtains as a result of chemistry. Bottom line: When charged particles from the sun strike atoms in Earth's atmosphere, they cause electrons in the atoms to move to a higher-energy state. When the electrons drop back to a lower energy state, they release a photon: light. This process creates the beautiful aurora, or northern lights. [Video]

Why are displays different colours?

Displays can vary in intensity – from a glowing curtain of greenish yellow lights, dancing in the distance to a spectacular, multi-coloured fusion stretching across the sky. Most people lucky enough to see the aurora witness a display of neon green lights but if you are really lucky then that display might be yellow and red, or even multi-coloured.

The differences depend on two main factors: what type of gas is reacting with the solar particles and at what altitude this activity is taking place. Most of it occurs 100-200km above the Earth – a level where ‘excited’ nitrogen atoms glow green and blue. And above 200km, oxygen atoms glow red when reacting with charged particles from the Sun.

For how long are the Northern lights visible?

Anywhere from 10 milliseconds to all night long, depending on the magnitude of the incoming solar event. Coronal holes consistently produce nice auroras but big solar flares and CME's-coronal mass ejections are responsible for global-wide aurora displays… the BIG shows!

How often do the Northern lights appear?

Basically every day, but you cannot see them during daytime. Anywhere from 21:00 to Sunrise (9pm to Sunrise). In the far north of Sweden during the season it is almost a constant Kp-index of Kp2-3, the hi latitude makes it more likely that you will see them even if they are not so strong.

Will I see the northern lights?

Sightings of the northern lights can never be guaranteed, even when the conditions seem just right. Most people appreciate the northern lights are a natural phenomenon and we can’t turn them on for you!
But what we can do is get you to locations where sightings are generally known to be possible and better than anywhere else inside Stockholm. And what’s more, those places often offer beautiful seascapes as well as landscapes perfect for photography during the day when you are not stargazing.

Patience is the key as well as a clear, cloudless night. It is important to be away from any sources of artificial light, such as street lighting. Displays can occur any time from around 5pm but most activity tends to be after 21:30pm Sightings not only vary in intensity but in duration too, from just minutes to sometimes hours.

Can you hear the Northern lights?
What do the northern lights look like to the naked eye?

What is space weather?
The term “cosmic weather” is usually understood as a set of phenomena on the Sun, in the upper atmosphere, near-Earth space and interplanetary medium, affecting the processes in near-Earth space.

Observations of space weather are associated with the monitoring of processes occurring in outer space and the initiator of which, in one way or another, is the sun. These processes can affect public infrastructure systems, including telecommunications systems and avionics, biological objects (--> they can affect people's health).

The primary source of disturbances are variations of solar radiation, and the transfer of disturbances is carried out by waves and particles in the interplanetary medium, the magnetosphere, and the Earth’s ionosphere. First of all, these disturbances affect those processes in which the steady balance of electric currents and magnetic fields plays a significant role. Disturbances that disturb this equilibrium can lead to various emergency situations not only in navigation, communications, electric power, but also in seemingly weakly related industries, such as extinguishing forest fires, pumping oil through pipelines or healthcare.

Auroral currents can cause damage to power lines and corrosion in oil and gas pipelines. Magnetic storms, accompanied by the emergence of ionospheric irregularities, prevent the propagation of RF radio and navigation signals from GPS satellites, and the polar cap absorption (PCA) can severely hinder or completely terminate RF communications on transpolar flight lines, requiring changes in flight routes to lower latitudes. Irradiation of spacecraft with energetic particles of solar flares and the radiation belts of the Earth can cause equipment failures, damage to solar batteries and sensors.

Geomagnetic Substorm

An aurora, or what scientists call a 'Geomagnetic Substorm' or 'Polar Magnetic Substorm', goes through three distinct phases:

  1. Growth
  2. Expansion
  3. Recovery

Acknowledgement
Glendale App

What's a Magnetometer?

When the Earth is passing through a plasma cloud, the collisions of charged particles in the upper atmosphere cause disturbance to the Earth's geomagnetic field. A magnetometer is a device that measures deviations in the Earth's magnetic field, which might indicate that there is an aurora in progress. The greater the disturbance, the better the aurora is likely to be. The relationship between magnetometer readings and actual auroras in the sky is quite complex. It is possible to have strong auroras in the sky when the magnetometers are at seemingly background levels. Norwegian magnetometers provide the best correlation to visible auroras than UK-based ones. In many cases, UK magnetometers fail to detect activity or react a couple of hours after the light show started.

Growth

The Growth Phase usually starts around 1-2 hours before the expansion phase, although it can start several hours before. It is where we see a very slow fading-in of the aurora as a pink/red band that is approximately 10 degrees high on the Isle of Skye and sits above the horizon. It typically coincides with a climb in the magnetometer plots. This type of aurora is called a 'diffuse aurora'. During the growth phase, the diffuse aurora gets brighter and the discrete green arc begins to rise up over the horizon inside it. We can use this to get advance warning of the expansion phase and approximate when it might start.

Acknowledgement
Glendale App

Expansion

The Expansion Phase is the one that aurora-hunters seek, as this is when the aurora explodes into the brightest colours and biggest rays. It is when the magnetometers dip sharply downwards.

Acknowledgement
Glendale App

Recovery

In the Recovery Phase, the intense burst of activity during the expansion phase is waning and the magnetometers are returning to background levels. The aurora can remain for many hours after the magnetometers have normalised.

Acknowledgement
Glendale App

What does Kp index mean?

 

The Kp-index is a scale used to characterize the magnitude of geomagnetic disturbances. A geomagnetic storm starts at Kp5 after which the G-scale is also used.

Example chart from NOAA showing a Kp8 storm

 

  • Kp0 = Quiet
  • Kp1 = Quiet
  • Kp2 = Quiet
  • Kp3 = Unsettled
  • Kp4 = Active
  • Kp5 = Minor storm (G1)
  • Kp6 = Moderate storm (G2)
  • Kp7 = Strong storm (G3)
  • Kp8 = Severe storm (G4)
  • Kp9 = Extreme storm (G5)

The K-index quantifies disturbances in the horizontal component of earth's magnetic field with an integer in the range 0–9 with 1 being calm and 5 or more indicating a geomagnetic storm. It is derived from the maximum fluctuations of horizontal components observed on a magnetometer during a three-hour interval.

Natural Phenomenon

A phenomenon, in a scientific context, is something that is observed to occur or to exist. This meaning contrasts with the understanding of the word in general usage, as something extraordinary or outstanding.

Phenomena are categorized in a number of ways. Natural phenomena are those that occur or manifest without human input. Examples of natural phenomena include gravity, tides, biological processes and oscillation.

Here are a few of the many possibilities, types of natural phenomena include: Weather, fog, thunder, tornadoes; biological processes, decomposition, germination; physical processes, wave propagation, erosion; tidal flow, and natural disasters such as electromagnetic pulses, volcanic eruptions, and earthquakes.

  • Social phenomena are those that occur or exist through the actions of groups of humans. Six degrees of separation, for example, is a phenomenon that is demonstrated in social networking.
  • Psychological phenomena are those manifested in human behaviors and responses. The sunk cost effect, for example, is the tendency for humans to continue investing in something that clearly isn’t working. Another psychological phenomenon, the Hawthorne effect is demonstrated by an improvement in human behavior or performance as a result of increased attention from superiors, clients or colleagues.
  • Visual phenomena include optical illusions, such as the peripheral drift illusion in which people perceive movement in static images like Kitaoka Akiyoshi's rotating snakes.

The word phenomenon is derived from the Greek verb phainein, which means to show, shine, appear, to manifest or to be manifest.

SWPC?

Space Weather Prediction Center
https:www.swpc.noaa.gov

Ap index?

The Ap index quantifies the global daily average activity level of the geomagnetic field. The 27-day forecast of the Ap index is performed using the Auto-regressive Integrated Moving Average (ARIMA) method and it is based on the work of McPherron (1999) in their paper “Predicting the Ap index from past behavior and solar wind velocity” [doi:10.1016/S1464-1917(98)00006-3]. The Ap forecast is based on identifying recurring geomagnetic activity. Thus, it will not forecast transient activity. This will also affect the quality depending on the solar cycle, with best results in the declining phase, while almost random results otherwise.

 

The Ap-index provides a daily average level for geomagnetic activity. Because of the non-linear relationship of the K-scale to magnetometer fluctuations, it is not meaningful to take the average of a set of K-indices. Instead, every 3-hour K-value will be converted back into a linear scale called the a-index. The average from 8 daily a-values gives us the Ap-index of a certain day. The Ap-index is thus a geomagnetic activity index where days with high levels of geomagnetic activity have a higher daily Ap-value.

How do you determine the Ap-index?
The daily Ap-value is obtained by averaging the eight 3-hour values of ap for each day. To get the these ap-values you first need to convert the 3-hour Kp-values to ap-values. Be aware that we use the official, finalized Kp which comes from the GFZ in Potsdam, Germany. This Kp-index works slightly different then the preliminary Kp-index. Read about this in our Kp-index help article. To make it a bit more clear on how you can determine the Ap for a certain day, we will work with an example: we take one day with the following measured Kp-values: 0+, 2-, 2o, 3o, 7-, 8o, 9- and 9o. The next step would be to convert these Kp-values to ap-values. The table at the bottom of this article will help you with this. When we are done converting we get these eight ap-values: 2, 6, 7, 15, 111, 207, 300 and 400. The average of these eight values will give you the Ap for that day. The day that we used in this example day would have an Ap-value of 131. The table below will let you convert the Kp-values to ap-values.

Kp index

Kp index

The Kp index provides a measure of the planetary geomagnetic activity ranging from 0 to 9.
It is derived for each 3-hour interval from the K-indices at 13
geomagnetic observatories around the globe located at northern and southern latitudes between around 35° and 60°.
The K-index is a quasi-logarithmic scale from 0 to 9, specific to each observatory, which indicates
the range of geomagnetic activity within each 3 hour interval.

Kp or K Index?

K is a measure of how much geomagnetic disturbance there is at a particular location on the globe. The higher the K number, the better the aurora. Putting it another way, the higher the K number of the aurora was, the more gutted you will be that you missed it.

Kp is a 3-hour average of K readings from across the planet.
Kp values are used for global scientific studies and have no practical use for aurora-hunters wishing to see the lights in Stockholm. We could have a major substorm in progress in the Sweden but other parts of the world are calm, so when averaged out the Kp becomes very low. What is important for aurora-hunters is the K (not Kp) value at magnetometers around 10 degrees North of their own location. To use an analogy, say the Kp was the average temperature in every capital city in the world in a three hour period, then what use would it be in finding out whether it is frosty in Stockholm at the moment?

For this reason any aurora apps, web-sites and FB groups that use Kp values are totally unreliable and should be avoided. If you feel the need to monitor 'plots' then the go to Magnetometers provide the closest approximation to visible auroras in the SWE.

Or you can just use our favorite app.

Bz and Bt?

Bz and Bt are measures of the strength and direction of the interplanetary magnetic field between Earth and Sun. Using a simple analogy, think of the aurora as being like the light from a rechargeable torch. When the Bz is south (negative), the torch is charging. How long the light lasts, and how bright the display, depends on how long it was on charge and how strong the charge was.

GFZ?

German Research Centre for Geosciences.

SSA?

ESA Space Situational Awareness Programme’s.
http://www.esa.int/Our_Activities/Operations/Space_Situational_Awareness

Magnetometer?

When the Earth is passing through a plasma cloud, the collisions of charged particles in the upper atmosphere cause disturbance to the Earth's geomagnetic field. A magnetometer is a device that measures deviations in the Earth's magnetic field, which might indicate that there is an aurora in progress. The greater the disturbance, the better the aurora is likely to be. The relationship between magnetometer readings and actual auroras in the sky is quite complex. It is possible to have strong auroras in the sky when the magnetometers are at seemingly background levels. Norwegian and Swedish magnetometers provide the best correlation to visible auroras.

G1, G2 and G3?

G1, G2 and G3 are alternative names for Kp 5, Kp 6 and Kp 7 respectively.

CME?

A Coronal Mass Ejection is a plasma blob that the sun periodically emits from active sun-spots. If the blob hits the earth's atmosphere it can cause some of the best auroras. It is rare to get a direct hit. Think of it like the sun sneezing and the chance of some of the snot hitting an 8000 mile wide rock that is 93 million miles away.

CME's are often described as 'full halo' or 'partial halo', and 'symmetric' or 'asymmetric'. 'Full halo' means a nice even spray of plasma. 'Partial halo' means a lumpy, uneven spray of plasma. 'Symmetric' means directly aimed at Earth. 'Asymmetric' means slightly skewed to one side, so not a direct hit. The ideal is a full halo, symmetric CME which will give a nice even spray of plasma aimed directly at us.

When the sun launches an earth-directed CME, it takes 2 to 3 days to reach the Earth.

CH HSS?

Using the above analogy, if a CME is a sneeze then a Coronal Hole High Speed Stream is runny nose. It is a constant leak of plasma from a hole in the sun's magnetic field that sprays out into space. When one of the coronal holes is facing towards the earth, we can have a gentle dribble of snot hitting our atmosphere and causing auroras that are less intense than those caused by CMEs but continue for days rather than hours.

Sky was purple, is that an Aurora?

Between nautical and astronomical twilight end times, it is not unusual for your test photo to capture a sky that is largely purple or navy blue. This is not an aurora, it is the refraction of the sunlight causing blues, indigos and violets of the colour spectrum to become visible.

Orange Aurora?

No. Orangey glows in the sky, particularly when reflected on clouds or visible in colour as orange by eye, are caused by light pollution from human settlements. The way to tell if a patch of colour is genuine is that you will have stars in it.

Affect of the Moon on Auroras?

On a clear night, the moon can actually improve the quality of your aurora photos by illuminating the landscape and, thereby, significantly reducing camera noise. The colours of the aurora take on lovely pastel shades and the images are quite stunning. However, when there is a big moon and very fine misty cloud, the clouds will be lit by the moon and make it difficult to photograph the aurora. This is because increasing the exposure to bring out the aurora colours will also amplify the moonlight on the clouds. When the moon is at 25-50% it gives the optimal illumination to the landscape without washing out the more subtle details and colours of the aurora.

ECMWF

The European Centre for Medium-Range Weather Forecasts

https://www.ecmwf.int/

Myths and Legends

  • The name ‘aurora borealis’ is credited to Galileo and means ‘northern dawn’.
  • Some Northern American Inuit call the aurora ‘aqsarniit’ (literally ‘football players’) because they believe that the lights are ancestral spirits kicking around the head of a walrus.
  • The old Norse explanation was that the strange, shimmering green lights were old maids dancing in the heavens.
  • Vikings believed the glowing lights were reflections from the shields of the Valkyries, maidens who transported fallen warriors to Valhalla.
  • Scandinavian fisherman called the sightings Herring Flash as they saw them as a sign of rich catches, believing them to be caused by light reflecting off vast shoals of lively herring.
  • Modern day myths exist too – the Japanese believe that babies conceived under the northern lights will become intellectuals.