The Northern Lights are on many people’s bucket lists. The celestial phenomenon occurs in the upper levels of our atmosphere. We’ve long sought explanations for these beautiful lights, and extensive research has come up with many answers. We thought we had it all covered until something strange happened. Recently, in Finland, a scientist discovered a new type of Aurora. Each Aurora we see has a classification, it makes it easier to describe. For example, these ripples and waves of light got a cool-sounding label like ‘corona’, which describes an Aurora straight above us. The one that appears as if it’s falling straight down. This new observation, labelled ‘dunes,’ was discovered by citizen-scientist Pirjo Koski and her team in Finland.
The University of Helsinki got a team together back in 2018 when this new Aurora was discovered. The team named the discovery ‘The Dunes’ because of the wave-like pattern they create. This pattern differs from other Aurora patterns. To explain this particular formation, one must understand what causes the Aurora in general. I wrote an entire book, The Complete Aurora Guide for Travellers and Photographers, which fully explains it. Here’s a condensed, quick-start guide for DIYP readers:
The Aurora
The Aurora
The Earth has two poles – North and South. They work just like a magnet. Another effect of the poles is a magnetic field around the Earth, protecting it from things in space. The Sun, on the other hand, doesn’t have two poles because it doesn’t have a stable, central core like Earth. Instead, it has magnetic fields all throughout its mass, which is constantly moving. The matter in the Sun, comprised of Helium, is not liquid or gas. It’s plasma, somewhere between the two states of matter. The magnetic flow on the Sun causes the plasma to build up at certain points on the surface. This magnetic energy pushes extremely large volumes of the plasma together. The repelling effect of magnetism pushes the plasma up from the surface. This plasma eventually breaks tension when the forces are too great. Plasma is forced away from the surface. This is called a solar flare, and the matter flying through space is called a solar wind. The plasma that comes towards the Earth interacts with our magnetic field and is largely pushed away. Some of the plasma comes into the poles because of the magnetic charges. The particles hit other particles in our atmosphere and exchange energy. The expelled energy is emitted as light. Voila, the Northern Lights. There’s more to it, but that’s the gist.
The Dunes
The Dunes
What differs with the dunes, is that the lights occur in a Mesopheric Bore. This is the result of airflow trapped between layers of our atmosphere. When the Earth receives the particles from the solar wind and they subsequently fall into a Mesopheric Bore, they become charged at this point and light up. This is merely a visualization of the Mesopheric Bores. To gather more information on the dunes, stargazers gathered at various locations until they were seen again. A few nights later the dunes appeared once more. Their position was plotted using surrounding stars as reference. The dunes were recorded as being 60 miles (97 km) above the Earth’s surface. This level is right between the stratosphere and the thermosphere, and is the coldest point in our atmosphere. Personally, I am addicted to the Northern Lights. I get to the Arctic as often as I can to try and catch a glimpse. I reached out to the photographer who caught the dunes, Pirjo Koski, to get some insights. Here’s what she said, and some more of her dune photos, exclusively for DIYP: –
