The Vera C. Rubin Observatory Just Opened and It Will Change Astronomy Forever

The Vera C. Rubin Observatory in Chile began its 10-year survey of the entire southern sky in 2026. Here is what it will discover and why astronomers are treating it as the biggest thing in a generation.

The Vera C. Rubin Observatory, perched on Cerro Pachón in Chile at an elevation of 2,682 metres above sea level, began its operational 10-year Legacy Survey of Space and Time in early 2026. The Legacy Survey's specifications — imaging the entire southern sky every three nights for a decade, with a camera so large it contains more than three billion pixels and can photograph a region the size of 40 full moons in a single exposure — represent a step change in observational astronomy whose scientific harvest will be processed and studied for decades after the survey concludes.

The scale of the expected discoveries is quantified by astronomers who have been anticipating the survey's data for twenty years: approximately 20 billion galaxies photographed. 17 million transient events per night — supernovae, variable stars, asteroid movements, gravitational wave optical counterparts. An estimated 5-6 million new near-Earth asteroids whose existence and orbits will be documented for the first time. And the specific dark matter and dark energy measurements that the survey's unique combination of depth, area, and cadence makes possible for the first time.

Dark energy — the mysterious force causing the universe's expansion to accelerate — is one of physics' most profound open questions. The Rubin Observatory's survey will measure the positions and shapes of billions of galaxies with sufficient precision to detect the subtle statistical patterns of 'weak gravitational lensing' that reveal the distribution of dark matter throughout the universe. Comparing observed dark matter distribution with the theoretical predictions of different dark energy models will provide the best test yet of whether our current understanding of cosmology is correct or requires fundamental revision.

For asteroid planetary defence: the survey will detect near-Earth asteroids down to 140 metres in diameter — the size threshold above which an impact would cause regional catastrophe. Currently, NASA estimates it has found approximately 40 percent of asteroids above this size threshold. After ten years of Rubin observations, that estimate is expected to rise above 90 percent, providing humanity with the comprehensive inventory of threat objects that planetary defence strategy requires.