Christmas Lights From Space

The holiday spirit can now be quantified and measured — as a brightening of nighttime lighting so distinctive that, if you have the right technology to observe it, is visible from space.

Such is the upshot of a new series of powerful NASA satellite-based composite images, showing major increases in night lighting in many U.S. and global cities during the holidays — and especially in the suburban areas surrounding them.

For instance, here’s what the D.C.-Baltimore area looks like (anything colored green means there is more nighttime light at this time of year than in other seasons):


The image above is based on data from the Suomi National Polar-Orbiting Partnership satellite, whose Visible Infrared Imaging Radiometer Suite, capable of glimpsing the side of the Earth that is facing away from the sun, is responsible for the famous “Earth at Night” pictures that we’ve all seen before.

So what’s the reason for increased lighting?  It’s simple, says NASA’s Miguel Román, a physicist at the NASA Goddard Space Flight Center who conducted the research behind the images with Eleanor Stokes, a NASA fellow and Ph.D. student and at Yale.  “What you’re seeing here, anywhere you see green, is Christmas lights from space,” says Román.

“If you look at the spatial trend, you will find, a lot of the green in the DC area is concentrated in the suburbs,” he adds.

The composite images are based on the period from the end of Thanksgiving through the first week of January.  Only cities not under regular snowfall in winter could be imaged in this way (snow reflects light).

Overall, the researchers found that nighttime lighting increased by 20 to 50 percent in U.S. cities and suburbs during the holiday period, and that suburbs tended to light up more than urban centers.  The images are based on data from 2013.