Every night, a satellite photographs the planet in the dark and humanity draws its own map — deltas, coastlines, railways, oil fields, fishing fleets. It is the most honest settlement map we have, and the places it leaves blank are the argument.
The night map exists because a weather satellite was too sensitive.
The US Air Force flew the Operational Linescan System to see moonlit cloud at night. In 1973 Thomas Croft reported what else was in the film: city lights, gas flares, fishing fleets. A continuous digital archive only began in 1992. The modern instrument — the VIIRS Day/Night Band on Suomi NPP, launched 28 October 2011 — images the whole planet every night at 750 m, gridded to 500 m, and has done so without a gap since January 2012.
Radiance rises from empty desert to city core — but the sensor has a blind side.
The Day/Night Band is panchromatic across roughly 500–900 nm. It does not see blue. White LEDs peak right there, below 500 nm, so a city that swaps sodium lamps for LEDs can look dimmer from orbit while emitting more light on the ground. Kyba and colleagues flagged this directly: satellite growth figures are a floor, not a ceiling.
Where statistics are thin, brightness stands in for output.
Henderson, Storeygard and Weil showed that a 1% change in a place’s luminosity corresponds to a 0.28% change in its GDP. For countries with weak national accounts they recommend weighting measured growth and light-predicted growth about equally. The map’s real gift is that it ignores borders: you can measure a district, a delta, a corridor.
The blank areas are two different things — nobody there, or no power there.
In 2022 the number of people without electricity access rose for the first time in over a decade, to 685 million; 570 million of them live in sub-Saharan Africa. North Korea reads as a hole between two of the brightest countries on Earth: 57.5% of its people have access at all. And Egypt shows the opposite failure of intuition — the lit ribbon is under 5% of the national territory and holds about 97% of the nation.
Some of the brightest marks on the map have no address.
Gas flaring hit 167 billion cubic metres in 2025 — the highest in the satellite record since 2019, and the third straight annual rise. It burns in the Bakken, the Permian, the Niger Delta, the Gulf and western Siberia, printing city-scale light where almost nobody lives. Out at sea, VIIRS finds 10,000–20,000 lit boats on a typical night that broadcast no AIS or VMS position at all. Of the lit vessels that do match a transponder, just over 40% are squid jiggers, whose lamps are bright enough to read from orbit.
Lit area grew 2.2% a year; when it shrinks, something has gone wrong.
Between 2012 and 2016 Earth’s artificially lit outdoor area grew 2.2% per year and its total radiance 1.8% per year — and only a handful of countries held flat or fell. Because the composite is nightly, the same data reads backwards: after Hurricane Maria crossed Puerto Rico on 20–21 September 2017, NASA’s Black Marble product was used to map which neighbourhoods had power back and which did not, week by week. Falchi’s atlas puts the cumulative result plainly: 83% of humanity now lives under a light-polluted sky.
A night-lights map is not a population map and never was. It is a map of electrified, outdoor, after-dark human activity — which correlates with people, but fails in both directions: flares burn brightly with nobody home, and 685 million people live under a pixel that reads as empty. Read it as a map of where the grid reaches and who can afford to leave it on, and it becomes one of the sharpest instruments in geography.
Egypt is a single lit thread with a fan at the top — under 5% of the country, about 97% of the people.
North Korea sits dark between Seoul and the Chinese coast. 57.5% electricity access.
Cyan marks are flares and fishing fleets: bright, mapped, and almost uninhabited.
A dashed line of towns across Siberia is a railway, drawn by lamplight.
Australia, the Sahara, the Amazon and the boreal north are dark because nobody is there. Much of central Africa is dark for a different reason.
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