What Does Christmas Look Like From Space?

Christmas is well-known as the holiday of lights. Each year, people string bright lights outside their homes as a way to commemorate the holiday. Christmas lights are one of the things that make the holiday so joyous. Over the past few years, scientists have had some fun tracking and analyzing our use of holiday lights. They did so from outer space, where they could watch how the United States lit up during the holidays.   The Initial Tests A few years ago, scientists sent a few radiometers into space. Radiometers can measure waves of light and act as either an ultraviolet detector or infrared detector. Once the radiometers were in space, researchers remotely pointed them toward Earth. They then began tracking the Earth during the nighttime. If scientists witnessed a night free of clouds, they would snap a picture of the Earth’s surface using the radiometers. This allowed them to see the lights. The goal of the project was to track how lights changed from day to day on a broad scale. Between 2012 and 2014, scientists captured thousands of pictures of more than 70 cities in the United States.   Tracking The Holidays What particularly caught the attention of researchers was the way the light patterns changed during the holiday season. In the time between Thanksgiving and New Year’s Day, scientists were able to see a noticeable difference in the brightness of the lights in the United States. Because they had years of data, scientists were able to tangibly measure the difference in light outputs between the holidays and non-holidays. Miguel Roman, a scientist with NASA, was the lead researcher on the project. In all, he said his team needed more than three years worth of data to reach definite conclusions but that they were now capable of tracking changes in lights across different cities at any given time. Roman’s team concluded that during the holidays, major cities in the United States shined up to 50 percent brighter than they did during non-holiday seasons. The team also found that the most significant difference occurred in the suburbs surrounding cities, as opposed to the centers of the cities themselves. This is likely because lights are always on throughout the night in the city centers, whereas the lights made a profound impact where it is typically dark at night. Additionally, perhaps the most exciting conclusion is that Roman’s team found the results to be universal. Meaning, they did not find that income or ethnic background impacted the intensity of the lights. During the holidays, the lights were brighter everywhere, meaning everyone across the country was sharing holiday cheer. Roman has said that he plans to continue his study as his team seeks to explore other areas of the world. His team has recently begun to analyze the Middle East. It will be interesting to see what conclusions they can draw based on when other areas of the country celebrate their major holidays. Until then, we can only continue to celebrate the Christmas season!   [embed][/embed]