It is one of the most bewitching shows on the planet. The lights of the northern lights. They have always fascinated experts and amateurs and can be seen at the magnetic poles of the northern and southern hemispheres. A discovery in Finland could drive auroras hunters crazy. It is the finding of a new northern lights.
It was a joint effort of amateur researchers and astronomers in Finland. The phenomenon is an amazing spectacle of green light that forms waves in the night sky. It is caused when electric solar particles enter Earth’s atmosphere and collide with gases such as oxygen and nitrogen.
Minna Palmroth, Professor of Computational Space Physics at the University of Helsinki, received an invitation to join a Facebook group of Northern Lights fans. It’s called Northern Lights. Palmroth published at the end of 2018 a book entitled Revontulibongarin Opas (“A guide for Northern Lights observers”). It was born from the teacher’s cooperation with Facebook enthusiasts.
By an incredible coincidence, days after the book was published, fans observed an unusual form of aurora and immediately informed Palmroth. It was a shape that showed a “pattern of waves that looked like green-colored striped clouds or dunes on a sandy beach,” says the study published in the magazine AGU Advances.
Looking at the sky
«One of the most memorable moments of our collaboration was when the phenomenon appeared at that specific moment. We were able to analyze it in real time, ”says one of the Northern Lights group members. He is an amateur astronomer, Matti Helin.
The northern lights can come in many forms. That includes “quiet arches,” spirals and haloes. The phenomenon occurs when the Sun emits a constant flow of charged particles, known as solar wind.
Upon reaching the upper atmosphere, the ionosphere produces electromagnetic radiation. They release oxygen and nitrogen atoms creating the visual effects of the aurora.
As part of her project, Professor Palmroth asked amateur astronomers to capture images of particular forms of the aurora.
A new northern lights
But then the mystery arose: “Some of them asked me: y and what are these stripes, what shape are they?”, Says the teacher.
It was a new northern lights that did not fit into any of the categories that already existed. Fans took thousands of photographs that were subsequently analyzed.
After studying them, the researchers concluded that “the dunes” “are a field of monochromatic waves. They have a wavelength of approximately 45 km of a thin layer of the atmosphere at a relatively low altitude of 100 km, in the upper parts of the mesosphere.
The mesosphere is the layer of the atmosphere located above the stratosphere at approximately 50 to 80 km high.
According to the study, the dunes show waves of the atmosphere, which are possibly perforations in the mesosphere, which are rarely detected and have not been observed before in latitudes and auroral altitudes.
The area where the northern lights form in an extremely challenging area for satellites and other space instruments.
That is why it is one of the least studied places on our planet, Palmroth explains.
Holes in the mesosphere
“Due to the difficulties in measuring the atmospheric phenomena that occur between 80 and 120 km of altitude, we sometimes call this area‘ the ignosphere, “he says. The “dunes” were observed precisely in that particular region of the auroral zone. “In the end we proposed that the dunes are the result of an increase in the density of oxygen atoms,” says Palmroth.
Thus, the study concludes that the phenomenon of “dunes” are perforations in the mesosphere. A rare and poorly studied event that occurs in that layer of the atmosphere. And that produces a new northern lights, an unexplored form so far. How important it is to look at the sky carefully, from time to time!