"The night is nowhere as dark as we might think."
That's the word from Mitch Goldberg, program scientist for the National Oceanic and Atmospheric Association's Joint Polar Satellite System. Together with NASA, scientists have unveiled a new composite, cloud-free image of our planet at night.
The imagery, which was posted to NASA's website on Wednesday, shows the planet bathed in cool blue, with city lights radiating out in sinewy yellow splotches.
The pictures that make up the massive composite image were taken over nine days in April and 13 days in October of this year, by an instrument on a satellite that's "sensitive enough to detect the nocturnal glow produced by Earth's atmosphere and the light from a single ship in the sea," NASA states. The satellite collected 2.5 terabytes of data in 312 orbits of the planet "to get a clear shot of every parcel of Earth's land surface and islands."
And the picture is stunning: Spin west to east across the U.S. and you see the brightness of Seattle, Portland and Los Angeles giving way to the Great Basin and the Rockies; the ordered grid of Midwestern cities and counties draw lines of lights to Dallas and Chicago.
And down in the Gulf of Mexico, ships and oil rigs dot the water. In Africa, bright yellow traces the Nile River delta.
NASA says that in addition to just making pretty pictures of the planet, the specialty camera will aid in nighttime forecasting, giving researchers clearer pictures of storm, fog and other weather conditions. And the optics aboard the Suomi NPP satellite isn't just your standard issue 5D with a superlens; the imager repeatedly scans a scene and turns it into pixels. Then the images are evaluated. If the signal in each pixel is too dark, it's amplified; if it's too bright, it's prevented from oversaturating.
"It's like having three simultaneous low-light cameras operating at once and we pick the best of various cameras depending on where we're looking in the scene," Steve Miller, a researcher at NOAA's Colorado State University Cooperative Institute for Research in the Atmosphere, tells NASA.
We cut a few smaller images from the huge global map. But if you want to download and explore the original image yourself, you can. There's even a gargantuan, 54000 x 27000-pixel image, guaranteed to crash any browser, for those who dare.