Exactly half the planet is in daylight at any instant — that half never changes size. But people are not spread evenly across the globe; they pile up in the longitudes of Asia and Europe. So the share of humanity standing in the sun is almost never one half. It breathes from barely a sixth to nearly nine-tenths and back, once a day, every day, as the lit half sweeps from the empty Pacific across the crowded Old World.
Drag the map or the curve to push the sun around the planet and watch the count rise and fall. The bright ribbon is the lit half of Earth. The dots are where the 7.33 billion of us actually live, weighted cell by cell — and you can see them ignite and go dark in waves.
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There is a second, slower truth underneath the daily swing. — Because so much more of humanity lives north of the equator, the average daylit share over a whole day is not 50% either — it leans toward the season the northern hemisphere is having. Near the June solstice the sun rides high over the crowded north and the daily mean tips above half; near December it dips below.
The peak comes when the sun stands over Africa and the Middle East around mid-morning UTC: Europe, all of Asia, and Africa are lit at once — the Old World, where roughly six in seven people live. The trough comes half a day later, when noon is parked over the open Pacific and only the Americas are awake to it.
How this is built. Population: NASA SEDAC
Gridded Population of the World v4 (2015 estimate), aggregated to a 1°×1° grid — 18,771 populated cells totalling 7.326 billion. A cell is counted "in daylight" when the sun's centre is above its horizon (solar elevation > 0°), computed from the subsolar point using the standard NOAA solar-position approximation (declination + equation of time) for your device's current UTC time. No atmospheric refraction or twilight is added, so the count is the strict geometric day side. Population is from 2015; the daily
pattern is insensitive to the exact year. Grid via
openaddresses/population; coastlines from Natural Earth. Pure astronomy + a static census — no live feed, nothing to rate-limit.