NASA Releases Stunning “Blue Marble” Image of Earth
NASA released a new, high-resolution "Blue Marble" image of Earth this week, taken from instruments aboard the recently launched Suomi NPP satellite. The image is actually a composite of many pictures from Jan. 4, 2012 that were stitched together, and shows North America in stunning detail. One feature that is notably absent from the picture is snow cover, which is confined to parts of the Rocky Mountains and Sierra Nevada.
In many parts of the country, snowfall has been running well below average so far this year.
The image was taken by one of the five instruments aboard the NPP satellite, known as the Visible/Infrared Imager Radiometer Suite or VIIRS. According to an article in the LA Times, the image was put together by a NASA oceanographer named Norman Kuring, as a favor to a NASA scientist who asked for a visual image to use for a talk at a scientific conference.
The LA Times explained how the image was put together:
"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. Kuring made the image above by running code that translates that data into an image.
"VIIRS only scans one swatch of Earth at a time, measuring about 1,900 miles across. Kuringer says you can think of it as if you were walking down the street with a broom and sweeping as you go. The images are then pieced together to make a whole."
The original "Blue Marble" image, which had the effect of encouraging people to look at their planet in an entirely different light, was taken from the moon by Apollo 17 astronauts in 1972.
This week, NASA renamed the NPP satellite in honor of the late Vernor Suomi, a scientist at the University of Wisconsin who “pioneered remote sensing of Earth from satellites in polar orbits.” Specifically, Suomi invented a “spin-scan camera” that paved the way for the satellite images seen on television weathercasts.