How about that! 99% of the world’s population in sunlight simultaneously?

[a425couple]

Go to
https://earthsky.org/earth/99-percent-worlds-population-receive-sunlight/

and view the graphic

July 8 … 99% of the world’s population in sunlight simultaneously?
Posted by
EarthSky Voices

July 6, 2022
World's population: Flat map of Earth showing light areas where daylight
shines and dark along the bottom 2 edges.
View larger. | Timeanddate’s Day and Night World Map for 11:15 UTC on
July 8. It shows most of the world’s landmasses in sunlight. Sure, about
90% of the world’s population lives in the Northern Hemisphere. But can
99% of global population experience sunlight simultaneously? Timeanddate
fact-check below. Image via Timeanddate.com.
Timeanddate.com originally published this article by Konstantin Bikos on
July 4, 2022. Reprinted here with permission. Edits by EarthSky.

You might have seen this fascinating tidbit circulating the internet:
For a moment each year, on July 8, 99% of the world’s population gets
sunlight. Is it true? Konstantin Bikos, lead editor at Timeanddate.com,
fact-checks this claim.

Same moment of sunlight for 99% of the world’s population
As July rolls around, our number crunchers thought it was worth
fact-checking a July-related claim that has been making the rounds on
the internet lately.

In the original post, Reddit user GiddySwine presents a still image of
our Day and Night World Map, claiming that 99% of the world’s population
is between dawn and dusk on July 8 at 11:15 UTC.

A more widely circulated version claims that 99% of the population gets
daylight at that moment.

The Day and Night World Map
A brief look at our Day and Night World Map gives some initial support
to the claims (see image above). Nearly all of the world’s most
populated areas receive some sunlight at the time in question. Among
them are North America, South America, Europe, Africa and most of Asia.

Australia, New Zealand, parts of Southeast Asia and Antarctica are the
only larger landmasses on the night side of Earth.

In this map, you can see day, night and the three stages of twilight.
The lightest shading represents daytime when the sun is above the
horizon. The darkest shading is nighttime when the sun is below the
horizon, and there’s no twilight. The shadings between day and night are
the three stages of twilight when the sun is below the horizon, but
there’s still some indirect sunlight.

July 8: 99% of the world’s population gets some degree of sunlight
When we run the detailed numbers through our computer, we also find some
support for the claim.

Combining Timeanddate’s sun data with 2022 population data from the
Center for International Earth Science Information Network at Columbia
University, we found that it’s nighttime for just under 80 million
people on July 8 at 11:15 UTC.

That leaves about 7.7 billion people — roughly 99% of us — on the side
of the planet illuminated by the sun. Over 6.4 billion of them are in
the daytime, while more than 1.2 billion people experience the twilight.

So, with 83% of us getting direct sunlight and another 16% getting
indirect sunlight, the claims are, in one way, correct. And, before we
go any further, let us say that this alone is a fascinating fact and a
great find!

Here’s a graph showing how many people experience daylight on July 8 at
11:15 UTC. Most experience daylight, while some experience the twilight
(the sun is below the horizon but there is still some daylight to
brighten the sky) and a small fraction experiences the night. Image via
Timeanddate.com.
A pitch-black twilight sky

That said, there’s a hitch: a few hundred million people on the
supposedly sunlit side of Earth will think it’s the night.

This is especially true for those who reside on the outermost edge of
the twilight zones, within the darkest twilight phase called
astronomical twilight. Here, the sun is 12 to 18 degrees below the
horizon. At that angle, the indirect sunlight becomes so thin that it is
usually indiscernible to the unaided eye.

The trace amounts of light in the otherwise pitch-black sky are of
concern only in very particular contexts. For example, it can hinder
astronomers from observing the faintest celestial objects: hence the
name of this twilight phase.

Black trees in foreground and darkened sky with dots of light.
View at EarthSky Community Photos. | Sudhir Sharma took this image of
the morning planets on July 1, 2022, in Stormville, New York. Thank you,
Sudhir! During astronomical twilight, when the sun is 12 to 18 degrees
below the horizon, the eye usually fails to discern the trace amounts of
indirect sunlight in the sky.
There will be daylight, but people will perceive it as night
So, 256.8 million people, about 3% of the world’s population, are so far
behind the curve that no sunlight is visible.

Moreover, many people in the slightly brighter nautical twilight zone
will fail to notice any daylight. Especially in urban areas, whose
residents make up a majority of the total population numbers. Near
cities, light pollution can blend out the faint glow of the sun, which
is 6 to 12 degrees below the horizon at that point.

So, the claim is technically true if you count all twilight areas, no
matter how dimly lit.

But the percentage of the population actually perceiving sunlight is a
bit lower. Discounting all of the people in the astronomical twilight
zone and half of the population experiencing nautical twilight, we get
7,204.9 million people, or about 93% of the world’s population.

It’s still a very high number. But the wording of the more recent
versions of the post, claiming that 99% of the population will
“experience daylight,” is somewhat misleading.

Why July 8 and not the June solstice?
When doing this fact-check, one thing caught our attention: the date.

By far, most people reside in the Northern Hemisphere. The June
solstice, when the northern half of the globe receives the most
sunlight, falls on or around June 21. Doesn’t that mean even more people
get sunlight on the day of the June solstice than on July 8?

Well, yes and no. As before, it depends on if you account for human
perception or simply follow the technical definitions of the twilight
phases.

Following the technical approach, July 8 is indeed a better date than
June 21. As the sun slowly makes its way south after the solstice, its
rays gradually retreat from northern areas. However, at 11:15 UTC, this
change affects only largely unpopulated areas, such as the northern
Pacific Ocean.

At the same time, the sun’s southward movement extends its reach farther
south, for example, in Indonesia and the Philippines. Although the
change is tiny in geographical terms, it covers some of the world’s most
densely populated areas and adds about 10 million people to the twilight
and daylight zones.

Chart with day, night and types of twilight listed with 2 dates and how
many people experience each.
This chart shows how many people are experiencing day, night or one of
the types of twilight on the solstice compared with July 8. Image via
Timeanddate.com.
June 21 solstice: More visible sunlight for world’s population
Interestingly, while more people are on the night side of Earth at 11:15
UTC on the solstice than on July 8, the number of people experiencing
civil twilight — the brightest twilight phase — is also considerably
larger: 575.9 million people on June 21 and 548.0 million people on July 8.

So, of the people in the twilight zones, a larger percentage experience
discernible twilight on June 21.

If we again discount the astronomical twilight zone and half of the
nautical twilight zone, the total number of people actually noticing
sunlight increases to 7,218.8 million, nearly 14 million more than the
7,204.9 million people doing so on July 8.

11:15 UTC is the perfect moment for the world’s population
Whichever definition you use, the day-to-day difference is relatively
small during this time of the year.

However, one fact remains undisputed: 11:15 UTC is indeed the perfect
moment each day when dawn begins on the North American west coast while
dusk still reigns in East and Southeast Asia.

If you want to mark the moment when most of humanity is bathed in
sunlight, you can see the seconds tick down with our countdown.

And while you bask in the sun, please spare a thought for our friends
Down Under who are among the 1% experiencing actual nighttime at that
moment, irrespective of definitions and technicalities.

Bottom line: Fact-checkers at Timeanddate.com discovered it’s
technically true that 99% of the world’s population experiences some
sunlight at 11:15 UTC on July 8. But some of those experiencing it will
think it’s the night.

Via Timeanddate.com

[a425couple]

On 7/8/2022 6:14 AM, a425couple wrote:
> Go to
> https://earthsky.org/earth/99-percent-worlds-population-receive-sunlight/
>
> and view the graphic
>
> July 8 … 99% of the world’s population in sunlight simultaneously?
> Posted by
> EarthSky Voices
>
> July 6, 2022
> World's population: Flat map of Earth showing light areas where daylight
> shines and dark along the bottom 2 edges.

from the comments by readers

Murf. • 17 hours ago •★★★★★
★★★★★
Wouldn't the same effect occur 17 days prior to the summer solstice?

Stephen Meier Murf. • 16 hours ago
Astute.

Deborah Byrd Mod Stephen Meier • 4 hours ago
Yes, that was a good question by Murf.!

Ben Weaver Murf. • 15 hours ago
No. Seventeen days before the solstice, both sunrise and sunset occur
later in the day. During summer (for the northern hemisphere) Earth is
farther away from the sun than during winter. So it orbits the sun more
slowly, and thus takes less time to rotate around the distance the earth
covered in its orbit since the previous day. The latest sunset occurs
around June 9th, and the earliest around December 9th. This is why
summer is 3 days longer than winter (August v February), why you get
later sunsets overall in winter than fall, and why you get earlier
sunsets overall in summer than spring.

Deborah Byrd Mod Ben Weaver • 4 hours ago
Hi Ben, I'm impressed that you're thinking about this so deeply! A
couple of tweaks ...Yes, the earliest sunsets of the year happen before
the winter solstice. But this isn't a true statement: "Seventeen days
before the [summer] solstice, both sunrise and sunset occur later in the
day." The sequence around the summer solstice is always earliest sunrise
(before the solstice), longest day (on the solstice), latest sunset
(after the solstice). The sequence around the winter solstice is always
earliest sunset (before the solstice), shortest day (on the solstice),
earliest sunrise (after the solstice). The exact date of earliest
sunrise and latest sunset varies with latitude ... so it's not 17 days
for everyone.

[Daniel65]

a425couple wrote on 9/7/22 12:33 am:

(not having read the entire post) ... I would have thought a more
relevant factor would be that the major Landmasses are in the Northern
Hemisphere and the major populations are in the Northern Hemisphere ...
so whilst the potion of 'The Globe' lite would be similar, 'the
landmass' and 'population' portions lite would be less .... maybe not
drastically, but still less!
--
Daniel