Rubin Observatory Begins Decade-Long Survey of the Dynamic Universe

After years of planning, construction and testing, the NSF–DOE Vera C. Rubin Observatory has officially begun the Legacy Survey of Space and Time (LSST), a decade-long effort that will generate the most comprehensive time-lapse record of the universe ever assembled.  

Rubin's 8.4-meter Simonyi Survey Telescope and the world's largest digital camera will scan the visible southern sky, capturing everything from nearby asteroids to distant galaxies. By comparing images taken over 10 years, astronomers will be able to watch the universe change in unprecedented detail, tracking exploding stars, mapping billions of galaxies and probing some of the biggest mysteries in cosmology, including the nature of dark matter and dark energy. 

Building confidence in cosmic measurements   

Rubin is expected to image roughly 20 billion galaxies and 17 billion stars over the course of its survey while generating tens of terabytes of data every night. The resulting dataset will be used by researchers around the world to investigate subjects ranging from the structure of the Milky Way to potentially hazardous asteroids and the expansion of the universe.  

For physicists in the Duke Cosmology Group, including Arun Kannawadi and Chris Walter, the start of LSST marks the culmination of years of preparation and the beginning of a new phase of discovery. 

Kannawadi, an assistant research professor of Physics at Duke, focuses on one of the survey's most challenging tasks: ensuring that astronomers can reliably process information from the telescope's unprecedented volume of data. 

As Rubin begins its 10-year endeavor, Kannawadi said he is most excited to see what the scientific community is going to achieve with the new data. 

“LSST is designed to answer many questions from objects lurking around the edge of our solar system to the entire universe,” he said. “I am particularly looking forward to understanding the nature of dark energy and dark matter with the technique of weak gravitational lensing. Much of my own work in the past 10 years has been gearing up to measure the weak signal from the images that LSST will observe.” 

Fellow Duke cosmologists will also benefit from Rubin’s new data, including Michael Troxel and Dan Scolnic. Scolnic's research group, in addition to studying supernova for cosmology, also plans to use information from LSST for asteroid detection.

Preparing for discoveries no one can predict 

Walter is a professor of Physics, department chair and founder of the Duke Cosmology Group. He has spent years preparing Rubin for this moment. His involvement with the project began in 2013, and he spent 2022 and 2024 living in Chile helping build the telescope, test its systems and analyze how it performed and how it could be improved. 

One of Rubin's primary scientific goals is measuring weak gravitational lensing — the tiny distortions in the apparent shapes of distant galaxies caused by the gravity of invisible matter between those galaxies and Earth. Detecting these subtle signals requires extraordinary precision. Walter's research group develops methods for calibrating the observatory's measurements and analyzing the enormous datasets Rubin will produce. Their work helps ensure that slight distortions introduced by Earth's atmosphere, the telescope optics or the camera itself are carefully understood and corrected, allowing scientists to make the most of the survey's unparalleled precision. 

“It’s a great day, and now the next steps begin,” said Walter. “As the data from the telescope flows in, scientists from around the world and here at Duke will analyze it to understand the nature of our universe.”  

For Duke’s cosmologists, the observatory's transition from commissioning to full science operations represents a major milestone. 

“This moment is marking a new era in astronomy, not just in terms of the data volume and quality that LSST ushers in, but also how research in astronomy gets done,” said Kannawadi. “LSST is going to be a game changer, where science-ready data will be handed over on a giant plate (Rubin Science Platform) to the entire U.S. and Chilean scientific communities and to our international collaborators — and we are ready to dig into it.”  

“This science is what got me excited about working in cosmology in the first place and it also was the catalyst that started a large vibrant group here at Duke,” said Walter. “I’m proud to have worked with so many other people to get to this point, and excited to do the science we have all been waiting for.”