image: On March 6, 2016, social media feeds lit up with spectacular photographs showing the Northern Lights (Aurora Borealis) painting skies across the United Kingdom with brilliant shades of green and pink.
The event was spectacular from above as well. Using the day-night band (DNB) of the Visible Infrared Imaging Radiometer Suite (VIIRS), the Suomi NPP satellite acquired this image of the aurora borealis on March 7, 2016. Auroras appear as white streaks over Iceland, the North Atlantic Ocean, and Norway. The DNB sensor detects dim light signals such as airglow, gas flares, city lights, and reflected moonlight. In the image above, the sensor detected visible light emissions when energetic particles rained down from Earth's magnetosphere into the gases of the upper atmosphere.
Normally, the aurora is only visible in the United Kingdom from the far north of Scotland and Northern Ireland, but a strong geomagnetic storm colored night skies over a much wider swath of the country. The storm reached a G3 or "severe" level on NOAA's geomagnetic storm scale, according to the agency's Space Weather Prediction Center. On March 6, the Kp index--a metric for global geomagnetic storm activity--rose as high as 7 on a scale that goes to 9.
Credit: NASA/NOAA/NASA Earth Observatory (NASA Earth Observatory image by Jesse Allen, using VIIRS day-night band data from the Suomi National Polar-orbiting Partnership. Suomi NPP is the result of a partnership between NASA, the National Oceanic and Atmospheric Administration, and the Department of Defense. Caption by Adam Voiland. )