Michail Fragkias, a professor of economics, and coauthors recently published “Satellite imagery reveals increasing volatility in human night-time activity,” which was featured on the cover of Nature in April 2026. Nature is a weekly international journal considered one of the most authoritative journals in science and technology with one of the highest impact factors in the industry.
The group used satellite imagery to create global maps of humanity’s impact through artificial light at night (ALAN). While previous ALAN monitoring relied on monthly or yearly averages, the group’s use of daily nighttime satellite data allowed them to see more sudden spikes and drops in light.
“There was a race to publish this research. Our group was the first to publish a paper analyzing high resolution and frequency imagery and using it to observe what’s happening across the planet,” Fragkias said. “The brightening of the planet is a much richer story than was previously thought. The resulting time series on luminosity are like EKGs for human activity, showing that economic development is not a smooth process.”
After analyzing nearly a decade of daily satellite data, the researchers found that global nighttime light increased by 16% during that period and that the light is characterized by rapid and constant shifts. While some regions — particularly in China and India — are brightening quickly due to urbanization, other areas are dimming because of energy-saving policies, the transition to LED lighting or disruptions like the war in Ukraine and COVID-19 lockdowns.
As an economist, Fragkias is interested in the relationship between Earth’s nighttime illumination and economic output.
“I wanted to understand how light levels align with U.S. economic statistics and how this data could help us understand what’s happening in the developing world and other regions and cities where data is scarce,” he said. “We can potentially use these sensors pointed toward our planet as early warning technology to help us figure out if our systems are stressed, how they are recovering, and to monitor conflict, economic decline and prosperity among several things.”
Fragkias collaborated with 21 coauthors from 10 institutions across the world including NASA, Yale and Cornell. This research is part of a larger set of papers the group is working on, one of which is slated to be published in The Proceedings of the National Academy of Sciences and another targeting Science later this year.
“From an economic standpoint, we can’t simply say lights are a direct proxy for economic growth. It’s a complex question that needs to be studied further,” Fragkias said. “We’re doing more analysis to figure out exactly how much lights can tell us about disruptions, growth and decline of local, regional and national economies and how to use other data and technologies that can supplement our findings.”