According to the data, nighttime lights around many major U.S. cities shine 20 to 50 percent brighter during Christmas and New Year’s when compared to light output during the rest of the year. In some Middle Eastern cities, nighttime lights shine more than 50 percent brighter during Ramadan than the rest of the year.
To confirm that the nighttime signal was not just an instrument artifact, they examined three years worth of data from 2012 through the fall of 2014.
Certainly a cool piece of information, but just as certainly bad news for astronomers who’s greatest enemy is light pollution.
Because snow reflects so much light, the researchers could only analyze snow-free cities. They focused on the U.S. West Coast from San Francisco to Los Angeles and on cities south of a rough line from St. Louis to Washington, D.C.
In the United States, the lights started getting brighter on ‘Black Friday,’ the day after Thanksgiving, and continued through New Year’s Day, said Miguel Román, a research physical scientist at Nasa Goddard and member of the Suomi NPP Land Discipline Team, who co-led this research.
“Overall, we see less light increases in the dense urban centers compared to the suburbs and small towns, where you have more yard space and single-family homes,” said Eleanor Stokes, a NASA Jenkins Graduate Fellow and doctoral candidate at Yale University, who collaborated on the study with Román.