Lighting the Paths Across the U.S.
Thanksgiving is a time for family, for feasting, and for gratitude in the
United States. It is also a time when the nation’s transportation network is
clogged with travelers. According to the American Automobile Association, an
estimated 43.4 million Americans will travel 50 miles (80 kilometers) or more
during Thanksgiving week, with the average round trip being 600 miles (1,000
kilometers). More than 90 percent of them will use cars or trucks, while the
rest will ride planes or trains.
The United States has more roads—4.1 million miles (6.6 million
kilometers)—than any other nation in the world, and roughly 40 percent more than
second-ranked India. About 47,000 of those U.S. miles are part of the Interstate
Highway System, established by President Dwight Eisenhower in the 1950s. The
country also has 127,000 miles (204,000 kilometers) of railroad tracks and about
25,000 miles (40,000 kilometers) of navigable rivers and canals (not including
the Great Lakes).
The imprint of that transportation web becomes easier to see at night. The
Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi NPP (National
Polar-orbiting Partnership) satellite acquired two nighttime images early on
Oct. 1, 2013, for this natural-light, mosaic view of the continental United
States. The VIIRS instrument uses a “day-night band” of wavelengths that is
sensitive to low light levels and manmade light sources. The images were
collected just three days before the new moon, so reflected light from space and
the atmosphere was relatively low. It was also a rare night when most of the
nation was cloud-free.
Image Credit: NASA Earth Observatory image by Jesse Allen and Robert
Simmon, using Suomi NPP VIIRS and DMSP OLS data provided courtesy of Chris
Elvidge (NOAA National Geophysical Data Center)
Caption: Mike Carlowicz
Caption: Mike Carlowicz
Guillermo Gonzalo Sánchez Achutegui
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