Astronomers just began the largest cosmic time-lapse in history

The Vera C. Rubin Observatory in Chile has started a 10-year survey of the changing night sky

A dark sky filled with millions of pinpricks of light representing stars and galaxies.
A 1.7-gigapixel image of a field of stars 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 a backdrop of galaxies of all shapes and sizes.
NSF–DOE Rubin Observatory/NOIRLab/SLAC/AURA

Join Our Community of Science Lovers!

The biggest and best movie of the universe began production this week—at the new Vera C. Rubin Observatory in Chile, rather than in Hollywood.

This unique telescope is using the world’s largest digital camera to scan the entire southern sky every few nights, assembling what will become the most lavishly detailed time-lapse of the cosmos humanity has ever envisioned. Rubin will look for undiscovered asteroids (including potentially hazardous ones heading toward Earth), unimaginably powerful cosmic explosions, and clues about the shadowy dark energy and dark matter that shape the universe.

Rubin opened its eye to the sky—an 8.4-meter-wide starlight-gathering mirror—about a year ago, but scientists have been testing and fine-tuning its optics since then. It officially began its 10-year Legacy Survey of Space and Time (LSST) on June 30. “It’s an amazing feeling—I’ve been working for over two decades on it,” says Željko Ivezić, head of the LSST. “It reminded me of the birth of my child. You wait, you wait and finally it materializes. We’ve been hoping for this night for quite a while.”


On supporting science journalism

If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.


The 3,200-megapixel camera, built by the SLAC National Accelerator Laboratory, can take an almost inconceivably high-definition image of the sky every 40 seconds or so, and Rubin’s giant mirror offers an enormous, panoramic vista. “We have a large field of view about 100 times larger than that of similar telescopes, and can scan 100 times faster,” Ivezić says. The data Rubin will amass in 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 the changeable aspects of the heavens: sudden sparks of light, mysteriously vanishing stars, space rocks whizzing around the solar system, and the dark energy-driven accelerating expansion of the universe itself.

“After five to seven years we will be in a position to tell apart two major hypotheses about dark energy,” Ivezić says. Either dark energy is a real phenomenon, causing the universe to grow bigger at a faster and faster rate, or there is no dark energy at all, and scientists have somehow misunderstood the laws of gravity at cosmic scales. “If we manage to answer this question, that will be the most fundamental result of Rubin and LSST.”

The observatory will also likely discover millions of new asteroids, including ones that may be on collision courses with Earth. And it has revolutionary potential for studies of what astronomers call transients: flashes of light that abruptly appear and quickly fade. These include supernovae and other cataclysms, such as gamma-ray bursts (GRBs), some of which arise from colliding black holes or neutron stars and are among the most powerful explosions in the universe. Many aspects of the physics underlying GRBs remain enigmatic—but Rubin’s potential for discovering entirely new types of transients could soon offer astronomers a wealth of additional cosmic mysteries to solve.

Clara Moskowitz is chief of reporters at Scientific American, where she covers astronomy, space, physics and mathematics. She has been at Scientific American for more than a decade; previously she worked at Space.com. Moskowitz has reported live from rocket launches, space shuttle liftoffs and landings, suborbital spaceflight training, mountaintop observatories, and more. She has a bachelor’s degree in astronomy and physics from Wesleyan University and a graduate degree in science communication from the University of California, Santa Cruz.

More by Clara Moskowitz

It’s Time to Stand Up for Science

If you enjoyed this article, I’d like to ask for your support. Scientific American has served as an advocate for science and industry for 180 years, and right now may be the most critical moment in that two-century history.

I’ve been a Scientific American subscriber since I was 12 years old, and it helped shape the way I look at the world. SciAm always educates and delights me, and inspires a sense of awe for our vast, beautiful universe. I hope it does that for you, too.

If you subscribe to Scientific American, you help ensure that our coverage is centered on meaningful research and discovery; that we have the resources to report on the decisions that threaten labs across the U.S.; and that we support both budding and working scientists at a time when the value of science itself too often goes unrecognized.

In return, you get essential news, captivating podcasts, brilliant infographics, can't-miss newsletters, must-watch videos, challenging games, and the science world's best writing and reporting. You can even gift someone a subscription.

There has never been a more important time for us to stand up and show why science matters. I hope you’ll support us in that mission.

Thank you,

David M. Ewalt, Editor in Chief, Scientific American

Subscribe