Remember that weird Chris de Burgh song about the spaceman visiting earth at Christmas? As it turns out, extra-terrestrial visitors won’t have any trouble figuring out when the holidays are on this planet: research from NASA has shown that Christmas, where it’s celebrated, prompts such an increase in our use of lights that you can actually see the difference from space.
Scientists were sifting through images of earth to track our use of light when they noticed an odd seasonal pattern in parts of the United States. After accounting for factors like white, reflective snow, clouds or moonlight, the researchers found that light follows a yearly pattern of ups and downs: it drops in summer, as you might expect, but there’s a mysterious spike from about mid-November to the beginning of January. Guess what that spike is?
When they looked closer they found that, in eastern US cities and suburban areas (where snow doesn’t warp the results), light levels increased by anywhere between 20 and 50 per cent around Christmas and New Year, as everyone rolls out their fantastical light displays. This map shows the light patterns at this time of year:
Of course, cities are always very brightly lit at night – they’re brighter in December, but that’s hard to tell by just looking at the image above. The big change at this time of year is those smaller blobs between cities – normally, those areas are pretty dark, but the sudden invasion of enormous light displays in suburban areas, towns and villages makes a huge difference.
There’s more detail from NASA on the phenomenon in this clip:
The researchers found a similar pattern in some Middle Eastern cities during Ramadan, when Muslims fast during the day and so engage in more activity than usual at night. There, the effect was even starker – the green patches on this map show where the lights are 50 per cent brighter, or more, during the month of fasting.
Of course, lots more lights require more electricity, and therefore more fuel. That’s not necessarily a great thing from an environmental point of view – but somehow, we can’t find it in our hearts to mind very much. After all, festivities on earth are all very well and good – but there’s something genuinely awe-inspiring about the fact you can see them from space.
That’s it for our Advent Calendar, folks – have a great Christmas and happy New Year!
You can definitely see this one from space. Image: Michael Gil via Flickr.
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