A geomagnetic storm brewed over the United States last night as solar winds battered Earth’s atmosphere, setting off a magnificent display of glowing lights in the sky.
During the G2 level storm on September 18, spectacular ripples of aurora borealis were observed over several northern U.S. states, including Minnesota, Wisconsin, Wyoming, and Montana.
Traces of the aurora were even visible on camera as far south as Nebraska, according to spaceweather.com.
Geomagnetic storms are classified on a scale from G1 (minor) to G5 (extreme), making a G2 storm the second level of severity. They are usually caused by coronal mass ejections from the sun, also known as CMEs, which is when huge plumes of solar plasma and magnetism are thrown out of the sun’s surface due to the realignment of magnetic fields. This solar wind then propagates through space, sometimes towards Earth, at immense speeds of up to 6.7 million kilometers per hour.
The CME then collides with Earth’s magnetic field and ionosphere, where it interacts with gas molecules and causes strange effects, including auroras.
“A geomagnetic storm is the alteration of Earth’s magnetic environment. This means that the magnetic fields that usually surround our Earth begin to be distorted,” Daniel Brown, associate professor of astronomy and science communication at Nottingham Trent University in the United Kingdom. News week.
“Stronger storms will transmit more energy to electrons in our Earth’s magnetic environment or magnetosphere,” Brown said. “These electrons will then be the source of the light observed in the austral and northern lights, when they crash into the oxygen or nitrogen in our upper atmosphere, making them glow. The more energetic the electrons, the more the display is bright.”
G2 storms typically occur about 1,700 times per 11-year solar cycle, according to NASA’s G scale. The stronger the storm, the less frequent it is and the farther from the poles the effects of the Northern Lights are: G5 storms can cause the visibility of an aurora as far south as Florida or as far away as Australia.
“Aurora colors are the result of particles in the upper atmosphere being excited by collisions with particles from the magnetosphere and some from the solar wind,” said Brett Carter, associate professor of space science at RMIT University. in Australia. said News week earlier this year. “The different colors are the result of the relaxation of electrons from different energy levels, oxygen (the most common reds and greens) and nitrogen (the dark reds/blues).”
Therefore, the further south an observer is, the redder the Northern Lights will appear, as they will only be able to spot the fainter red hues emitted by oxygen at higher altitudes.
“This red color is usually pretty pale, because there aren’t a lot of oxygen atoms at such high altitudes,” Brown said. News week in February. “But if you have strong enough activity like we’re getting now, there are enough exciting particles in the coronal mass ejections to interact with more oxygen and make the red brighter.”
This is why there was a faint red aurora over Nebraska, which was only visible using a camera.
Geomagnetic storms can also have other effects on the planet, including problems with the power grid.
“These storms can influence much more than the power grid infrastructure,” Carter said. “GPS usage may be affected due to variations in the ionosphere, and the orbits of low Earth orbit satellites experience increased atmospheric drag due to swelling of the upper atmosphere.”
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