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The Vera C. Rubin Observatory, making a 10-year time-lapse of the night sky
Highlights
- The NSF-DOE Vera C. Rubin Observatory is a ground-based telescope in Chile built to survey the southern sky over and over for 10 years.
- Its Legacy Survey of Space and Time is expected to catalog about 20 billion galaxies, 17 billion stars, and the orbits of roughly 6 million Solar System objects.
- Rubin can spot near-Earth asteroids, making it a powerful new tool for planetary defense.
What does the Rubin Observatory do?
The Vera C. Rubin Observatory is making what its team calls an ultra-wide, ultra-high-definition time-lapse record of our Universe. The telescope photographs the entire sky visible from its position atop the El Peñón peak of Cerro Pachón, a 2,647-meter-high (8,684-foot) mountain in northern Chile. It repeats this every few nights and will continue doing so for 10 years, revisiting each patch of sky about 800 times.
This project, called the Legacy Survey of Space and Time (LSST), began on June 29, 2026. By June 2036, researchers expect Rubin to have cataloged about 20 billion galaxies, 17 billion stars, and 6 million Solar System objects.
Because Rubin keeps coming back to the same places, it can catch things that move or change, such as asteroids drifting through the Solar System and stars brightening or exploding. When such a change is detected, the telescope sends an alert to a network of other telescopes so that they can follow up.
Rubin’s primary science goals are understanding the nature of dark matter and dark energy, creating an inventory of the Solar System, mapping the Milky Way, and exploring objects that change position or brightness over time.
Rubin is a joint project of the U.S. National Science Foundation (NSF) and the U.S. Department of Energy’s (DOE) Office of Science.
How does Rubin contribute to planetary defense?
Unlike observatories that change their observations to look for specific targets in different parts of the sky, the Rubin Observatory photographs the same area repeatedly. It’s this steady view that gives it an enhanced ability to spot anything that moves between images. This is why Rubin is expected to find 5 to 10 times more Solar System objects, such as comets and asteroids, than were previously known.
This capability was evident very soon after Rubin began its survey. When the telescope released its first images on June 23, 2025, the team announced 2,104 never-before-seen asteroids found in about 10 hours of test observations. They included seven near-Earth objects, 11 Jupiter Trojans, and nine objects beyond Neptune.
None of the near-Earth objects Rubin has found so far pose a threat to our planet, but this ability to spot this kind of asteroid may be crucial if there ever is a space rock headed our way. Scientists have found most near-Earth objects larger than 1 kilometer (0.6 miles) across, but only about 40% of those larger than 140 meters (460 feet). Smaller asteroids are less reflective, making them more difficult to spot. But an impact by an asteroid that size could still devastate a region. The Vera C. Rubin Observatory is expected to raise the percentage of known 140-meter-plus asteroids to 70%.
Who is the Rubin Observatory named after?
This powerful telescope is named after Vera C. Rubin, an American astronomer whose work provided convincing evidence for dark matter. With her colleague Kent Ford, Rubin’s research showed that the speed of rotation of spiral galaxies should cause them to fly apart if the gravity of their constituent stars were all that was holding them together; one explanation for galaxies staying together was that they contained more mass than we could detect.
Working in astronomy in the 1960s through the 1980s, Rubin also pushed to open the field to women. Some of her observations took place at facilities that had never officially allowed women before, such as the Palomar Observatory.
The Rubin Observatory was given its name in 2019, three years after Vera Rubin’s death. It is one of the first major U.S. national observatories named after a woman.