It began in 2007 as a simple online request: help astronomers sort through images of galaxies faster than any single research team could manage. Nearly two decades later, that experiment has reached a staggering figure. Zooniverse, the world's largest platform for people-powered research, says its volunteers have now contributed one billion classifications to real scientific projects.
The number is hard to picture. NASA, which funds part of the platform, estimates that a billion classifications add up to roughly 2,000 years of full-time work – compressed into the spare moments of ordinary people around the globe. More than three million volunteers across 160 countries have taken part, each marking a dip in a star's brightness, confirming a moving object in a short video, or identifying an animal caught by a camera trap.
Zooniverse grew out of Galaxy Zoo, the original galaxy-sorting project, and was co-founded by the Adler Planetarium in Chicago and the University of Oxford, with the University of Minnesota as a key partner. Today it runs roughly 60 to 70 active projects at a time, spanning not only astronomy but also ecology, climate science, biomedicine and history. Together, its projects have supported more than 500 research efforts and over 550 peer-reviewed publications.
The scientific payoff is concrete. Through efforts such as Planet Hunters TESS, volunteers have helped discover exoplanets; others have flagged near-Earth asteroids, hunted for faint brown dwarfs, and informed wildlife-management decisions by tagging animals in trail-camera footage. NASA counts 31 projects it has sponsored on the platform since 2020, contributing 120 million classifications and helping produce nearly 100 scientific papers – many co-authored by the volunteers themselves.
"One billion classifications represents far more than a number," said Laura Trouille, the platform's principal investigator and a vice president at the Adler Planetarium. "It's one billion moments of curiosity transformed into meaningful contributions to research." The milestone lands soon after another: earlier this year Zooniverse passed three million registered volunteers – a reminder that some of modern science's heaviest lifting is being done, click by click, by the public.