In the winter of 1838-39, a French scientific expedition arrived in Northern Norway and the Altafjord to study natural phenomena in the High North. The expedition was led by the French naval physician and naturalist Paul Gaimard, and is subsequently known as the Gaimard expedition, or Research-expedition after the ship that was used. The journey was part of Northern Scientific Commission, a French government initiative to map natural conditions in the Arctic and Northern Europe, including Norway and Finnmark.
Northern Lights without a camera
Today, the Northern Lights are routinely documented with cameras, sensors and satellites. In the 1830s, however, there were no practical methods for photographing a phenomenon that constantly changes shape, height and intensity. The solution was analogue: the expedition brought along artists who drew what they observed in the sky.
These drawings were later published as posters and were widely distributed in Europe. Today, they are considered both relatively accurate contemporary representations of the Northern Lights and art historical documents from a time when science and visual communication were closely intertwined.
Explanation: Why couldn't the Northern Lights be photographed?
Photography existed in a very limited form in the 1830s, but exposure times were long and the equipment was not very sensitive to light. The Northern Lights change shape in seconds and were therefore impossible to «freeze» in a photo. It wasn't until the end of the 19th century that it became technically possible to photograph the Northern Lights.
Parallax in practice
The most technically interesting aspect of the expedition was the attempt to calculate the height of the Northern Lights above the ground. The method was based on a principle that is still used in astronomy and space travel: parallax. By observing the same aurora structure at the same time from two locations at a known distance, geometry can be used to calculate the height.
According to later sources, the observation posts were located in Bossekop and Djupvik. At the time, the results were considered uncertain. Northern Lights researcher Sophus Tromholt wrote in 1885 that the measurements did not give satisfactory results and pointed to the short distance between the observation posts as a possible explanation.
Explanation: What is parallax?
Parallax is a geometric principle in which the apparent position of an object changes when it is observed from two different locations. By knowing the distance between the observation points and the angle difference of the object, you can calculate the distance - or height - mathematically. The principle is used in everything from eye measurement of distances to modern space travel and satellite navigation.
Striking numbers - seen through modern eyes
With today's knowledge, the measurements appear in a new light. The French scientists Auguste Bravais and V. Lottin estimated the height of the Northern Lights at between 90 and 150 kilometres. Physicist Asgeir Brekke pointed out in 1982 that this is a remarkably good estimate, as modern research typically places the average height of the Northern Lights at around 110 kilometres.
Alta Museum has later summarised this in a precise manner: The calculations from 1838-39 are close to the results of far more advanced studies carried out later by Tromholt and Størmer.
Explanation: How high is the Northern Lights really?
The Northern Lights occur when charged particles from the sun collide with gases in the atmosphere.
- Can stretch up to 500 kilometres during heavy activity
- Typical altitude: approx. 100-120 km
- Can occur as low as 80 km
The foundation for a northern light centre
Today, when Alta is associated with northern lights research, the mountain observatories at Halde and Talviktoppen are often mentioned. However, the French expedition shows that much of the methodological foundation was laid earlier, near the fjord.
Bossekop had good observation conditions, a stable horizon and accessibility throughout the winter. The expedition in 1838-39 therefore stands out as an early technological and methodological breakthrough in the understanding of the Northern Lights - and as an important explanation of why the Alta area later took centre stage in international Northern Lights research.
We have several such small pieces of the Northern Lights story from Halde in stock - stories about people, places and experiments that helped shape what we know today about the Northern Lights.
In the following flashbacks, we will move further along this line, a little closer to how the phenomenon gradually came to be understood. Those who wait rarely wait in vain.
See you in the next stroke of the pen
Håkon