HOT SPRINGS – Social media was literally lit up with photos of dazzling colors created by the aurora borealis last Tuesday night, Nov. 11, when the “northern lights” made an unusually dramatic appearance over much of the upper half of the United States.
According to several meteorological websites, the lights are caused by the interaction between the Earth’s magnetic field and charged particles from the sun’s atmosphere that enter the earth’s atmosphere. A solar flare (energetic particles from the sun) floats through space on the solar wind, eventually penetrating the Earth’s magnetic field.
The magnetosphere is a region of space around the earth that protects us from the worst radiation from the sun and typically deflects these particles around the earth. When the magnetosphere is overwhelmed, there is a bigger reaction and the result is the northern lights.
When the charged particles hit the earth’s outer atmosphere, they collide with various gases and create the lights that we see. These gases get “excited” and turn colors. For example the reds and greens were “excited” oxygen gas reactions some 60-150 miles above the earth’s surface. The yellow, pinks and whites are because of “excited” oxygen and nitrogen gas closer to the surface.
While it’s not entirely uncommon for South Dakota residents to see the northern lights, these colorful displays are much more common in the far northern latitudes (and far south latitudes). They also don’t typically display as vibrant colors as what was seen in the area last week, which made it an even more rare and special event for area residents to witness and photograph.