The Vera C. Rubin Observatory in Chile has begun a 10-year study of the changing night sky
By Clara Moskowitz edited by Lee Billings

A 1.7 gigapixel image of a star field in the constellation Lupus taken by the Vera Rubin Observatory as part of its 10-year Legacy Survey of Time and Space. Millions of multi-colored stars are visible against the backdrop of galaxies of all shapes and sizes.
NSF-DOE Rubin/NOIRLab/SLAC/AURA Observatory
Filming for the biggest and best movie in the universe began this week, at the new Vera C. Rubin Observatory in Chile, rather than in Hollywood.
This unique telescope uses the world’s largest digital camera to scan the entire southern sky every few nights, stitching together what will become the most detailed time-lapse of the cosmos humanity has ever imagined. Rubin will search for undiscovered asteroids (including potentially dangerous ones heading toward Earth), cosmic explosions of unimaginable powerand clues about the shadow dark energy and dark matter that shape the universe.
Rubin opened his eyes to the skyAn 8.4-meter-wide starlight-collecting mirror was released about a year ago, but since then scientists have been testing and refining its optics. On June 30, it officially launched its 10-year Legacy Survey of Space and Time (LSST). “It’s an incredible feeling: I’ve been working here for more than two decades,” says Željko Ivezić, director of LSST. “It reminded me of the birth of my child. You wait and you wait and finally it comes to fruition. We’ve been hoping for this night for a while.”
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The 3,200-megapixel camera, built by SLAC’s National Accelerator Laboratory, can take an almost inconceivably high-definition image of the sky every 40 seconds or so, and Rubin’s giant mirror provides an enormous panoramic view. “We have a field of view about 100 times larger than that of similar telescopes and can scan 100 times faster,” says Ivezić. The data Rubin will accumulate over the next decade, he adds, would take any other observatory a millennium or more to capture.
The project, funded by the U.S. National Science Foundation and the U.S. Department of Energy, will focus on changing aspects of the sky: sudden sparks of light, mysteriously disappearing stars, space rocks whiz around the solar systemand the accelerated expansion of the universe itself, caused by dark energy.
“In five to seven years, we will be able to distinguish two major hypotheses about dark energy,” says Ivezić. Either dark energy is a real phenomenon, causing the universe to grow faster and faster, or there is no dark energy at all, and scientists have misunderstood the laws of gravity on a cosmic scale. “If we can answer this question, it will be the most fundamental result of Rubin and the LSST.”
The observatory will also likely discover millions of new asteroids, including those that could be on a collision course with Earth. And it presents revolutionary potential for the study of what astronomers call transients: flashes of light that appear abruptly and quickly fade away. These include supernovae and other cataclysms, such as gamma-ray bursts (GRB)some of which result from collisions of black holes or neutron stars and are among the most powerful explosions in the universe. Many aspects of the physics behind GRBs remain enigmatic, but Rubin’s potential to discover entirely new types of transients may soon offer astronomers a host of additional cosmic mysteries to solve.
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