While December’s days get shorter and shorter as nightfall comes increasingly earlier, holiday lights nevertheless shine beautifully against its dark backdrop. In fact, reports from NASA and the US National Oceanic and Atmospheric Administration (NOAA) have given proof that holiday lights can actually be seen from space through the use of the Suomi National Polar-orbiting Partnership (Suomi NPP). This climate-tracking satellite, launched in 2011, possesses its Visible Infrared Imaging Radiometer Suite (VIIRS), used to measure visible and infrared light emissions from Earth. From analyzing the first few years worth of data that the Suomi NPP has provided, researches discovered that around the holiday period, cities in the US, Canada, and Europe alongside other majority-Christian regions shone about 20-30% brighter than the rest of the year, with suburban and semi-rural areas reaching as high as 50% as a direct result of decorative lighting.
However, although this is true for majority-Christian regions, holiday lights are put up for a variety of reasons during the festive season, such as Christmas, Hanukkah, Kwanzaa, and New Year’s. In fact, NASA researcher Miguel Roman commented, “despite being ethnically and religiously diverse, we found that the U.S. experiences a holiday increase that is present across most urban communities,” with this same effect occurring in practically all US cities, notwithstanding their demographic makeup. Additionally, this brightness effect has also been noted to occur in many Muslim-majority countries during the month of Ramadan.
In order to capture the data, filters, algorithms, and analytical tools were used on the data in order to reduce the impact from other light sources, such as moonlight, to determine that, in fact, holiday lights were the culprit. Interestingly enough, despite more people living in cities, the suburbs and semi-rural areas trumped them in holiday light brightness — being explained as a result of outdoor lightning not usually being possible for apartment dwellers in the city and there being many more single-family homes possessing room for plenty of holiday lights in the suburbs coupled with the fact that many people return home from the city to visit family during the holiday season.
While this phenomenon typically refers to the cumulative effects of holiday lights in certain regions, a study performed by a group of physics students attending the University of Leicester, which was published in the student-run Journal of Physics and Special Topics, revealed the theoretical numbers necessary for a singular house to be visible from the International Space Station. Their findings unveiled that the supposed house would need an apparent magnitude of at least +6.5, or in other words, light emissions of around 10,600 lumens. Given that one LED bulb is typically around four lumens, you’d need around 2,638 LEDs to make your house visible from space, which would cost an estimated £500 (about $666).
One particular Texas Hill Country Town, Johnson City, has become known as the “Twinkliest Town in Texas” — the factor responsible for the name being its massive annual Lights Spectacular that’s been held for the past 36 years. Beginning as a fundraiser for local nonprofits with around 100,000 lights, today, about two million lights drape the Live Oaks behind the Blanco County Courthouse as the surrounding town square glows to match. Beginning on Saturday, November 29, the event brings about 8,000 people to Johnson City every holiday season — a particularly impressive number considering it is four times the number of residents.
NASA has reported seeing the grand lights of the city during this month-long event (running through January 4th), certainly pleasing Johnson City business owner and Lights Spectacular chair Rayette Bible, who hearteningly describes how “we see children playing together…[and] thousands of photos are taken. Every year, there are more than a few marriage proposals under the lights!”
