A second of worldwide darkness
For only a second on December 6, almost 9 in 10 individuals worldwide will concurrently expertise nighttime.
Just a few months in the past, our quantity crunchers fact-checked (and partially confirmed) an web declare that 99% of the world’s population gets sunlight at 11:15 UTC on July 8. This left us questioning: What in regards to the reverse state of affairs? At what exact instantaneous do most individuals expertise nighttime?
Like final time, we fed our computer systems with timeanddate’s sun data for 2022 and inhabitants knowledge from the Center for International Earth Science Information Network at Columbia College. We then calculated inhabitants knowledge for the day, the night time, and the three twilight phases for each minute of on daily basis of the yr.
Right here’s what we came upon.
December 6: Most individuals in nighttime
In accordance with our calculations, the second of most darkness occurs at 19:56 UTC on Tuesday, December 6, 2022. At that instantaneous, the sky shall be fully darkish for about 85.92% of the world’s inhabitants. At that second, night time reigns throughout the three most populous continents: Asia, Africa, and Europe (with very minor exceptions).
How can or not it’s nighttime for nearly everybody?
Identical to at some other second, the solar will illuminate one half of the globe at 19:56 UTC on December 6. The opposite half shall be darkish, and other people residing there’ll expertise nighttime.
The explanation why so many individuals shall be in darkness is that the world’s most populated areas shall be on the night time aspect of Earth at that second. That features almost all of Asia, which is dwelling to about 60% of all people.
In the meantime, the Americas, New Zealand, and most of Australia shall be bathed in daylight. Nevertheless, whereas being big landmasses, comparatively few individuals stay there. North and South America mixed solely make up about 13% of our worldwide inhabitants.
Two twilit runners-up
Whereas it’s nighttime for most individuals on December 6, there may be additionally a case to be made for each December 21 and December 27 as various moments of most darkness.
You see, our computer systems spit out December 6 because the outcome solely once we ask them to stick to the strictest definition of nighttime. This definition says the solar have to be at the least 18 degrees under the horizon.
If the angle is lower than 18 levels, it’s twilight. That’s the time within the morning and within the night when oblique daylight brightens the sky to some extent.
December 27: Seems like night time for most individuals
The factor is, the darkest of the three twilight phases, astronomical twilight, is hardly discernible from the night time. The solar is between 12 and 18 levels under the horizon throughout that twilight part. And the sky is so darkish that it appears like nighttime.
After we allowed our algorithms to incorporate astronomical twilight, they calculated 19:39 UTC on Tuesday, December 27, 2022, because the second of peak darkness.
In accordance with our numbers, 86.11% of the world’s inhabitants experiences both nighttime (85.23%) or astronomical twilight (0.88%) at that instantaneous.
That’s roughly 15 million extra individuals in comparison with the quantity we calculated for December 6. Nonetheless, it hardly strikes the needle on a world scale: The distinction accounts for a mere 0.19% of the world’s inhabitants.
December 21: Most individuals with out direct daylight
The second various instantaneous of peak darkness takes under consideration all twilight phases, together with nautical and civil twilight. Throughout these two phases, the sky is noticeably brighter. Nevertheless, there’s nonetheless no direct daylight.
Making use of this free definition of darkness, we arrived at 21:44 UTC on Wednesday, December 21, 2022, because the second when most of us should not within the daytime.
We calculated that this impacts 88.14% of the world’s inhabitants. Practically 9 out of 10 individuals on Earth!
What’s so particular about these dates?
We weren’t notably shocked that each one the dates fall within the northern winter. Most individuals reside north of the equator, and December is the month when the least amount of sunlight reaches the Northern Hemisphere.
However why does the variety of individuals in darkness (or quasi-darkness) peak on these dates? Why does nighttime have an effect on extra individuals on December 6 than on, say, December 5?
All of it is determined by how properly the form of the area affected by nighttime and twilight overlaps with the world’s most populated areas. That form adjustments very barely from someday to a different because the solar strikes southward earlier than the December solstice and northward once more after the solstice.
On the dates we discovered, it merely matches the contours of the world’s inhabitants facilities barely higher than on the day earlier than or after.
However once more, the distinction may be very, very small. Working example: In accordance with our calculations, the variety of individuals experiencing night time at 19:56 UTC on December 6 is 6,665,450,571; exactly 24 hours earlier, it’s 6,665,326,866. That’s a distinction of 123,705 individuals, a tiny margin on a world scale.
Discovering the exact minute
As for the time of day when most individuals expertise darkness, it’s principally when Asia, Africa and Europe are on the night time aspect of Earth.
Throughout that point of the yr, that occurs on daily basis at 19-something UTC. That’s when night time has simply fallen in Europe. It’s additionally when the primary solar rays of the brand new day haven’t but reached the far east of Asia.
That mentioned, you most likely observed that the time we calculated for December 21 (21:44 UTC) falls out of line. That’s as a result of the inclusion of nautical and civil twilight makes for a bigger geographical space. An space that now stretches all the way in which from Japan within the east to a few of North America’s most populous metropolitan areas, corresponding to New York and Montreal, within the west.
As you may see within the screenshots of our Day and Night Map, it is just when together with the 2 brightest twilight phases that any good portion of North America’s inhabitants joins the “darkish aspect.”
Wherever you’re, benefit from the darkish skies!
If this sounds too gloomy and may’t watch for days to get longer once more, allow us to sweeten the deal. Take a look at how a lot darkish skies have to supply throughout that point of the yr.
If the climate performs alongside, wrap up heat and go exterior to benefit from the spectacular Geminids meteor shower. At its peak on December 14-15, we anticipate about 150 taking pictures stars per hour.
Just a few days later, on December 22-23, the Ursids meteor shower peaks, bringing us about ten meteors per hour.
And whereas ready for the taking pictures stars to flit throughout the sky, you should use our Night Sky Map to identify planets and stars. Additionally, discover extra stargazing occasions in EarthSky’s Night Sky Guide.
Take it with a grain of salt
Whereas we’re assured in our calculations and knowledge units, figuring out how many individuals expertise nighttime at anyone second is a fairly messy enterprise.
For one, the world’s inhabitants isn’t static. It adjustments over time, and in some areas, it does so at a special tempo than in others. We primarily based our calculations on the newest dependable inhabitants knowledge we may discover, however they’re from 2020.
What’s extra, the margins are minuscule. Whereas our algorithms recognized a particular instantaneous when most individuals expertise night time, in addition they gave us loads of different dates and occasions in the course of the Northern Hemisphere winter with a nighttime inhabitants that’s only a tiny fraction smaller. We’re speaking a couple of tens of 1000’s of individuals. Peanuts in comparison with the world’s inhabitants.
Backside line: On December 6, the most important proportion of the human inhabitants sees a second of worldwide darkness.