U.S. Christmas lights seen from space

NASA’S EARTH OBSERVATORY/JESSE ALLEN

Americans sure do love their Christmas lights. It’s a love that even aliens orbiting Earth could notice, NASA scientists suggest.
Using data gathered in visible and near-infrared wavelengths by sensors on a NASA/National Oceanic and Atmospheric Administration satellite, researchers compared the average intensity of nighttime lights across the southern United States in December of 2012 and 2013 with the average measured in non-December months from January 2012 through autumn of this year. In urban areas, holiday lights boosted the average intensity of ground-based light by about 20%. But in the suburban fringes of metropolitan areas, light intensity typically grew by between 30% and 50%, the researchers report. (In this image highlighting the southeastern United States, areas in green depict places where holiday light intensity shone forth at levels as much as 50% or more brighter than normal. In yellow areas, holiday lights weren't brighter than normal.) Suburban areas probably displayed greater increases in light intensity due to larger yards and more single-family homes, the researchers explain. The growth in light intensity, like holiday excitement itself, begins the day after Thanksgiving and lasts until New Year’s Day and beyond. Similarly, some cities in the Middle East show a similar boost in holiday lighting during the month of Ramadan, which is marked by daytime fasting and nighttime festivities.