The Earth at night | New views from NASA satellite

Nasa Earth Observatory released on the 5th of December image of Earth at night, that are simply stunning. The images have been created using a cloud-free night images from a new NASA and National Oceanic and Atmospheric Administration satellite, the Suomi NPP satellite. The data were acquired over nine days in April 2012 and thirteen days in October 2012. According to NASA, it took 312 orbits to get a clear shot of every parcel of Earth’s land surface and islands. This new data was then mapped over existing imagery of Earth to provide a realistic view of the planet.

Scientists are using these images of Earth’s dark side to gain insight on human activity and poorly understood natural events.

For example, On July 15, 2012, the Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi NPP satellite captured this night-time view of the aurora australis, or “southern lights,” over Antartica’s Queen Maud Land and the Princess Ragnhild Coast.

The image was captured by the VIIRS “day-night band,” which detects light in a range of wavelengths from green to near-infrared and uses filtering techniques to observe signals such as city lights, auroras, wildfires, and reflected moonlight. In the case of the image above, the sensor detected the visible auroral light emissions as energetic particles rained down from Earth’s magnetosphere and into the gases of the upper atmosphere. The slightly jagged appearance of the auroral lines is a function of the rapid dance of the energetic particles at the same time that the satellite is moving and the VIIRS sensor is scanning.

The yellow box in the top image depicts the area shown in the lower close-up image. Light from the aurora was bright enough to illuminate the ice edge between the ice shelf and the Southern Ocean. At the time, Antarctica was locked in midwinter darkness and the Moon was a waning crescent that provided little light. (1)

Credit: NASA Earth Observatory/NOAA NGDC

 

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