Earth-watching satellite

NASA New Satellite Captures Blue Marble Earth Image

Suomi NPP, NASA’s newest Earth-watching satellite, has taken a high resolution image of Earth, one of the most beautiful such images ever created. The satellite, named after the “father of satellite meteorology,” Verner E. Suomi, is designed to create fabulous images of Earth, monitor for natural disasters and improve weather forecasts as well as our understanding of long-term climate changes. The image is a composite, created using a number of swaths of the Earth’s surface taken on January 4, 2012. It echoes the legendary “Blue Marble” photograph, taken by the crew of the Apollo 17 spacecraft on December 7, 1972. This particular image was made using data collected by the Visible Infrared Imager Radiometer Suite, which is on a satellite flying 512 miles above the Earth. VIIRS is not really a camera, rather it has a scanning telescope that measures the difference between the amount of light coming down to the surface of Earth from the sun as compared to the amount of light that is reflected back to the telescope. VIIRS only scans one swatch of Earth at a time, measuring about 1,900 miles across. The images are then pieced together to make a whole. The satellite it rides on Suomi NPP, which was launched in October, has been placed in a sun-synchronous orbit so that the satellite is over the equator at the same local ground time in each orbit. This is relevant because it explains why each slice of image is lit the same way even though the entire image of the Earth was taken over a period of several hours. The data that VIIRS collects is still in the process of being calibrated, but eventually scientists will be able to use it to measure ocean temperatures, tell us the location of fires, and track cloud formations.