NASA intern Jennifer Briggs, a physics student at Pepperdine University in California, discovered a new type of aurora in three-year-old footage of the Arctic Sky. Scientists were able to correlate the never-before-seen aurora to a sudden compression in Earth's magnetic field.
During an internship at NASA's Goddard Space Flight Center in Maryland, Briggs came across the aurora in photos from ground-based, all-sky cameras mounted in Svalbard, Norway, near the Arctic Circle.
The newly found type of aurora was short-lived and had a rare spiral that caught her attention. NASA said this made Briggs think of a seashell-- its twisting motions indicated the magnetosphere had a major disturbance. Indeed, data from NASA's Magnetospheric Multiscale mission (MMS) provided the dramatic compression of the magnetosphere.
Researchers were left puzzled as to why this magnetic "crunch" occurred, or why it forced the magnetic field to decrease in size so abruptly. But since there were no solar explosions to push against the magnetic field at that time, researchers believe it may have been triggered by an unprecedented storm in the area where Earth's magnetic field meets particles from the Sun.
"This motion is something that we've never seen before. This eastward and then westward and then spiraling motion is not something that we've ever seen, not something we currently understand," said Briggs.
According to the intern, the edge of the magnetosphere moved toward the planet's surface by 25 000 km (15 534 miles) in less than two minutes when this certain aurora took place-- it was over four times the Earth's radius.
To put it into perspective, it would take a commercial jet around 27 hours to fly that distance.
"You can imagine someone punching Earth’s magnetic field," Briggs described. "There was a massive, but localized compression."
The rapid dash of charged particles during an aurora borealis can cause disruption on electronic communications, GPS, move satellites out of orbit, put astronauts at risk, and even eradicate power grids if the explosion is massive enough.
The aurora's vibrant lights are a product of collisions between electrically-charged particles from the Sun and gases in Earth's atmosphere like nitrogen and oxygen.
Our planet's magnetic field usually deflects these charged particles. However, since the field is weaker at the poles, particles sneak through, resulting in aurora borealis near the North Pole and aurora australis near the South Pole.
Studying auroras enable scientists to observe what's happening in the ionosphere, and even farther out into the magnetosphere.
Featured image credit: Fred Sigernes/Kjell Henriksen Observatory, Longyearbyen, Norway/Joy Ng