Lights In The Darkness

Image Credit: NASA Earth Observatory image by Jesse Allen, using VIIRS day-night band data from the Suomi National Polar-orbiting Partnership


With the “day-night band” (DNB) of the Visible Infrared Imaging Radiometer Suite (VIIRS), the Suomi NPP satellite acquired this view of the aurora borealis on December 22, 2016. The northern lights stretched across British Columbia, Alberta, Saskatchewan, Manitoba, Nunavut, and Northwest Territories, areas that often fall under the auroral oval.

The DNB detects dim light signals such as auroras, airglow, gas flares, and reflected moonlight. In the case of the image above, the sensor detected the visible light emissions as energetic particles rained down from Earth’s magnetosphere and into the gases of the upper atmosphere.

The collision of solar particles and pressure into our planet’s magnetosphere accelerates particles trapped in the space around Earth (such as in the radiation belts). Those particles are sent crashing down into Earth’s upper atmosphere—at altitudes of 100 to 400 kilometers (60 to 250 miles)—where they excite oxygen and nitrogen molecules and release photons of light. The results are rays, sheets, and curtains of dancing light in the sky.

The Suomi National Polar-orbiting Partnership (Suomi NPP) satellite, built by Ball Aerospace in Boulder, Colorado, was launched on October 28, 2011. Since then, Suomi NPP has provided life-saving data to weather forecasters and has given scientists new tools to help monitor the health of our planet.

Suomi NPP observes Earth’s surface twice every day, once in daylight and once at night. The spacecraft flies 512 miles (824 kilometers) above the surface in a polar orbit, circling the planet about 14 times a day. Suomi NPP sends its data once per orbit to a ground station in Svalbard, Norway, and continuously to local direct broadcast users. Researchers world-wide are then able to use customized algorithms, or mathematical formulas, turning raw data into images to help manage quickly changing regional events, such as rapidly spreading forest fires, rushing flood waters and floating icebergs at the poles that could affect the shipping and fishing industries.
