NASA intern Jennifer Briggs discovered a new type of aurora in 3-year-old video footage of the Arctic sky.
Scientists connected the never-before-seen aurora to a sudden retreat, or compression, in Earth’s magnetic field, the first time scientists have seen an aurora caused solely by such a compression.
The aurora’s bright and colorful lights are a result of collisions between electrically-charged particles from the sun (the solar wind) and gases in Earth’s atmosphere, such as nitrogen and oxygen. Earth’s magnetic field usually deflects these charged particles, but since the field is weaker at the planet’s poles, this allows some particles sneak through, producing the aurora borealis near the North Pole and the aurora australis near the South Pole.
Researchers are unable to explain why this magnetic crunch happened or why it forced Earth’s magnetic field to decrease in size so suddenly and rapidly, but since there were no eruptions on the sun to push against the magnetic field that day, researchers think the crunch may have been caused by an “unprecedented storm” in the area where Earth’s magnetic field meets particles from the sun.
Whatever the cause, the mysterious compression produced the stunning twisting aurora in the video below, which was observed from an island in Norway.
‘Imagine someone punching Earth’s magnetic field’
When this particular aurora occurred, the edge of the magnetosphere moved toward Earth’s surface by about 25,000 km in under two minutes (more than 15,000 miles), according to Briggs. More than four times the Earth’s radius in less than two minutes!
To put this into perspective, it would take a commercial jet about 27 hours to fly that distance.
“You can imagine someone punching Earth’s magnetic field,” Briggs said. “There was a massive, but localized compression.”
Normally, Earth’s magnetic field diverts these charged particles, but it is weaker at the planet’s poles. This allows some particles to sneak through, creating the aurora borealis near the North Pole and the aurora australis adjacent to the South Pole.
The sudden dash of charged particles during an aurora borealis can interrupt electronic communications, confuse GPS, move satellites out of orbit, endanger astronauts and even eliminate power grids if the eruption is large enough.
Now let’s try to imagine what havoc a full-fledged magnetic reversal could cause.
https://www.businessinsider.com/new-aurora-borealis-crunch-earth-magnetic-field-2019-12
Thanks to scsi_joe for these links
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January 2, 2020 at 01:51PM
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