"The northern lights are caused by energetic, charged particles hitting our upper atmosphere, which are impacted by numerous factors in space, including the sun," explained England, an associate professor in the Kevin T. Crofton Department of Aerospace and Ocean Engineering. "During solar geomagnetic storms, there's a lot more of these energetic charged particles in the space around Earth, so we see a brightening of the northern lights and the region over which you can see them spreads out to include places like the lower 48 states that usually don't see this display."
Utilizing NASA's GOLD instrument, England and a team of researchers observed the most intense geomagnetic storm recorded in the past 20 years. Their findings were published in two studies in Geophysical Research Letters. The first study, led by Deepak Karan from the University of Colorado, Boulder, documented unprecedented shifts in the location and distribution of particles in the upper atmosphere. The second study, led by Virginia Tech alumnus J. Scott Evans, detailed significant changes in atmospheric composition and temperature.
England noted that the event revealed "delightful swirly patterns" and observed a striking movement of air away from the aurora, forming massive vortices larger than hurricanes. Key findings included:
+ Unexpected movement of low-energy charged particles from the equator towards the aurora
+ Identification of charged particles split into low-energy and high-energy categories, with the latter posing risks to astronauts and satellite electronics
+ Temperature and pressure changes that likely triggered the observed swirls and vortices
+ Alterations in the distribution of low-energy particles, which can disrupt GPS, satellites, and even the electrical grid
"As the aurora intensifies, you see more lights, but along with that, there's more energy entering the atmosphere, so it makes the atmosphere near the poles very hot, which starts to push air away from the poles and towards the equator," England said. He added, "This data poses a lot of questions like, did something really different happen during this geomagnetic storm than has happened previously, or do we just have better instruments to measure the changes?"
The research also raises concerns about the potential impact of these changes on technology orbiting within this volatile atmospheric region.
Beyond the Light Show
The upper atmosphere, which ranges from about 60 to 400 miles above Earth, is home to satellites and the International Space Station. While similar in composition to the lower atmosphere, the upper atmosphere also contains the ionosphere-a highly charged layer that can be compared to an "electric blanket." The charged particles within the ionosphere contribute to its dynamic nature, with temperature and composition changes occurring regularly due to factors such as the sun's activity.
England explained that solar geomagnetic storms, triggered by intense bursts of solar radiation, cause significant shifts in particle behavior within Earth's atmosphere. He also addressed why the northern lights have recently been visible in unexpected locations: "The number of sunspots, flares, and storms changes with an 11-year cycle that we call the solar cycle. The number of flares we are seeing has been increasing gradually for the last couple of years as we move toward the peak of the solar cycle."
Geomagnetic storms can also affect technology on Earth. Radio and GPS signals, which pass through the ionosphere, are vulnerable to disruptions caused by changes in this layer. These storms can also induce electrical currents that impact long-wired technological systems, as seen in the Carrington Event of 1859, where telegraph systems were set ablaze.
Scientists caution that a similar storm today could trigger an "internet apocalypse," causing widespread outages. Although the May 11 storm did not lead to major disruptions, the peak of the current solar cycle is expected in July 2025, leaving the potential effects uncertain.
"One reason we study geomagnetic storms is to try and build models to predict their impacts," England said. "Based on the solar cycle, we'd expect the conditions we're seeing this year to be around for about the next two years."
Research Report:GOLD Observations of the Thermospheric Response to the 10 - 12 May 2024 Gannon Superstorm
Related Links
Department of Aerospace and Ocean Engineering at VT
Solar Science News at SpaceDaily
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