The mystery of the strange milky-white rays of light sometimes seen from the Northern Lights has finally been solved.
Formally called “structured continuous emission,” this glow may actually be the result of atmospheric warming driven by auroras, according to a new journal article. Contact with nature.
This grayish-white light has been observed by scientists for a long time, but until now it has never been fully explained.
“You see this dynamic green aurora, you see a patch of red aurora in the background, and suddenly you see this structured, almost irregular, gray or white emission. The aurora,” said study co-author and University of Calgary physics professor Emma. Spanswick said in a statement.
– So, the first response of any scientist is: “Well, what is it?”
ISTOCK / GETTY IMAGES PLUS
The northern and southern lights are caused by solar particles falling into the Earth’s atmosphere, due to persistent solar wind or during coronal mass ejections.
Earth’s magnetic field acts as a protective shield that keeps most of the solar wind away from the planet, but near the Earth’s poles the magnetic field lines converge and allow some of the solar wind particles to enter the planet. Earth’s atmosphere, especially the geomagnetic storm.
Jonty Horner, professor of astrophysics at the University of Southern Queensland in Australia, said: “The stronger the storm, the farther the pole appears, because the Earth’s magnetic field is more loaded with charged particles.” News week.
Once in the atmosphere, these charged particles collide with gas molecules in the atmosphere. Green light is produced by oxygen molecules at lower altitudes, while red light is produced by oxygen molecules at higher altitudes. Blue and violet lights are produced by nitrogen molecules, often at lower altitudes.
A special new sensor technology made it possible to capture the night sky in true colors and allowed researchers to study white light in detail.
“These grayscale structures range in size from 10 to 100 km. They are embedded within and/or preceded by active auroras (high-contrast structures that vary on time scales of less than a few minutes) and are distinguished in their spectra. Auroral emission components are the main factor in its formation,” the researchers wrote in the article.
According to the researchers, these white lights appear due to a combination of heating in the ionosphere due to the surrounding aurora, as well as chemiluminescence from some other gas in the atmosphere, possibly nitrogen dioxide.
Spanswick, E., Liang, J., Houghton, J., Chaddock, D., Donovan, E., Gallardo-Lacourt, B., Keenan, C., Rosehart, J., Nishimura, Y., Hampton, D. ., & Gillies, M. 2024. Association of structured continuum emission with dynamical aurora. Contact with nature.
Among the researchers was UCalgary undergraduate Josh Houghton, who was initially hired as an intern in the lab.
“At that time I was still learning things,” he said in a statement. “I just started an internship and got involved very quickly. “It’s really cool.”
The discoveries come after renewed interest in another strange atmospheric phenomenon: a narrow strip of purple or white light across the sky called Strong Thermal Emission Velocity Enhancement, or STEVE.
“There are similarities between what we’re seeing now and STEVE,” Spanwick said. “STEVE manifests as a purple or gray structure.
“To be fair, the spectrum height between the two is very similar, but because it is associated with the dynamic aurora, it is absorbed almost poleward. If you look at it, it’s harder to make out, and STEVE separates from the aurora. Crossing the sky a large group passed by.
This study shows that the northern lights and ionosphere may be much more complex than we thought.
“Contextualization with dynamical variability, mesoscale morphology, and auroral structures distinguishes our observed persistent emission structures from the previously studied NO2 continuum, or STEVE,” the researchers wrote in the paper.
“Our findings suggest that the coupling between auroral processes, plasma and the neutral atmosphere may evolve at the mesoscale and is more complex than previously reported.”
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References
Spanswick, E., Liang, J., Houghton, J., Chaddock, D., Donovan, E., Gallardo-Lacourt, B., Keenan, C., Rosehart, J., Nishimura, Y., Hampton, D. ., and Gillies, M. (2024). Association of structural continuum emission with dynamic aurora. Contact with nature, 15(1).
