NASA confirms visibility of Christmas lights from space orbit.
Revamped and Expanded Guide:
Get ready to light up your neighborhood, because it's time for the holiday season! Many of us will adorn our homes and yards with twinkling Christmas lights, but sometimes this can create inter-neighbor disputes. Some homeowners put up a simple holiday decoration, while others go all out. Here's how our neighbors with extravagant displays compare to the city lights seen from space.
The Nightlight Paradox: Holiday Lights Illuminate the Urban Sky
Contrary to what you might think, it's indeed true that we were right all along! From a cosmic perspective, those bright, blinking Christmas lights are visible from space. This information comes from none other than NASA and the US National Oceanic and Atmospheric Administration (NOAA).
The Suomi National Polar-orbiting Partnership (Suomi NPP), jointly operated by NASA and NOAA, houses the Visible Infrared Imaging Radiometer Suite (VIIRS) instrument. By analyzing the data collected over the years, researchers noticed something intriguing: around the holiday season, several cities in Christian-majority countries appeared between 20-30% brighter at night compared to the rest of the year. This brightening effect was even more dramatic in suburban and semi-rural areas, reaching 50%!
By employing sophisticated algorithms to filter out various sources of light and determining the brightness over time, researchers found that these enhanced nighttime cityscapes were indeed the result of millions of residential Christmas lights.
The video below showcases the satellite data's findings, highlighting the regions with increased holiday brightness and identifying major city centers around the world.
Miguel Roman, a NASA researcher, stated in an interview, "Despite being ethnically and religiously diverse, we found that the U.S. experiences a holiday increase that is present across most urban communities." Interestingly, a similar phenomenon was observed during the month of Ramadan over majority-Muslim cities.
Can My Humble Christmas Lights Be Seen from Space?
You may be thinking, "But they're talking about entire towns, not the lights on house 43." Well, while it may seem implausible, it's not completely out of the question!
In 2017, a group of physics students at the University of Leicester wanted to find out just how ridiculous the idea of a single house's Christmas decorations being visible from space really was. These students defined "visible from space" as "seen from the International Space Station" and calculated that for a house to be seen from that altitude, it would need an apparent magnitude of at least +6.5. This estimate equates to 10,600 lumens - roughly the combined brightness of 2,638 LED bulbs, or about £500 worth when assuming no light pollution.
Though these findings are a theoretical estimate, they provide a fascinating glimpse into the possibilities of solar observations from space. It's clear that while individual houses and their Christmas lights are not typically visible from space, cities and large urban areas can still be seen under the right conditions.
As NASA puts it, "By looking at the lights we can see changes in human behavior throughout the seasons... more than 70% of emissions come from cities. So NASA is putting a lot of emphasis on understanding cities and [how they're] interacting with the climate and our system as a whole."
In the holiday spirit of giving, let's spread some light and cheer in our neighborhoods without worrying about being seen from the cosmos!
Insights on Estimating Christmas Lights Visibility:To determine how many LED bulbs are needed to make a house's Christmas lights visible from the ISS, several factors must be considered, including the brightness of the LED bulbs, visibility thresholds from orbit, atmospheric effects, and light pollution levels.
The researchers' estimate of 500,000 to 1,000,000 LED bulbs is a theoretical lower limit, assuming ideal conditions (e.g., no light pollution, clear weather, and a direct line of sight). In reality, brightness and contrast with neighboring areas would play a significant role in the visibility of a single house from space.
[1] Luminosity and How it Impacts Visibility from Space
- Despite the misconception, the array of twinkling Christmas lights on houses during the holiday season can be visible from space, as revealed by NASA and NOAA's satellite data, showcasing an intriguing urban brightening effect of up to 50% in suburban and semi-rural areas.
- While an individual house's Christmas lights may not be visible from space under normal circumstances, the collective brightness of millions of residential Christmas lights can indeed light up cities and large urban areas, offering a unique perspective on human behavior and city interactions, as acknowledged by NASA researchers.
