On a mountaintop in northern Chile, the world’s largest digital camera is preparing to start up.
The mission is simple but ambitious: photograph the entire night sky in incredible detail and unlock some of the deepest secrets of the universe.
Housed in the Vera C. Rubin Observatory – a new telescope nearing completion on Cerro Pachón, a 2,682-meter-high mountain about 300 miles (482 kilometers) north of the Chilean capital Santiago – the camera has a resolution of 3,200 megapixels, approximately the same number of pixels as 300 cell phones, and each image covers an area of the sky the size of 40 Full Moons.
Every three nights the telescope will image the entire visible sky, producing thousands of photos that allow astronomers to see anything that moves or changes in brightness. In this way, Vera Rubin is expected to discover approximately 17 billion stars and 20 billion galaxies that we have never seen before – and that’s just the beginning.
“There’s so much that Rubin will do,” said Clare Higgs, the observatory’s astronomy outreach specialist. “We’re exploring the sky in a way we’ve never done before, allowing us to answer questions we haven’t even thought about asking yet.”
The telescope will survey the night sky for exactly ten years, taking a thousand photos every night. “Ten years from now we will be talking about new areas of science, new classes of objects, new types of discoveries that I can’t even tell you about now because I don’t know what they are yet. And I think that’s something really exciting,” Higgs adds.
Prepare for switching on
The telescope, which has been under construction since 2015, is named after pioneering American astronomer Vera Rubin, who died in 2016 and, among other things, confirmed for the first time the existence of dark matter – the elusive substance that makes up most of the matter in the universe, but never observed.
The project was kickstarted in the early 2000s by private donations, including from billionaires Charles Simonyi and Bill Gates. It was later jointly funded by the Department of Energy’s Office of Science and the U.S. National Science Foundation, which also manages it along with SLAC National Accelerator Laboratory, a research center managed by Stanford University in California.
Although Rubin is a US National Observatory, it is located in the Chilean Andes, a location it shares with several other telescopes for a number of reasons. “For optical telescopes you need a location that is high, dark and dry,” says Higgs, citing the problems of light pollution and humidity, which reduce the sensitivity of the instruments. “You want a very quiet and well-understood atmosphere, and the quality of the night sky in Chile is exceptional. That’s why there are so many telescopes here,” she adds. “It’s remote, but not so remote that getting the data off the mountain is a problem. There’s an infrastructure that Rubin can lean on.”
The telescope is currently in the final stages of construction and is expected to be switched on in 2025. “We’re currently in the process of assembling all the parts, but they’re all on the mountaintop – that’s a big milestone we achieved this summer,” says Higgs. “We expect things to happen in the spring of next year: bringing everything together, aligning everything, making sure that all the systems from the top down to our pipelines and the data look the way they should and are optimized as best as possible. we can. This has literally taken decades of preparation, but you never know until you turn everything on.”
After a few months of testing, the observatory will make its first observations in late 2025, although Higgs warns there is “liquidity” in this schedule.
“10 million alerts per night”
Rubin’s main mission is called LSST, which stands for Legacy Survey of Space and Time. “This is a ten-year study where we look at the southern sky every night, and we repeat that every three nights. So we’re essentially making a movie of the southern sky over ten years,” says Higgs.
The camera can take a photo every 30 seconds, which generates 20 terabytes of data every 24 hours, the same amount as the average person watching Netflix for three years or listening to Spotify for fifty years. When completed, the research will have generated more than 60 million gigabytes of raw data.
However, it only takes 60 seconds to transfer each image from Chile to California, where AI and algorithms will first analyze it, look for any changes or moving objects, and generate an alert if anything is found.
“We expect about 10 million alerts to come from the telescope per night,” Higgs said. “The alerts cover anything changing in the sky, covering a range of scientific cases, such as solar system objects, asteroids and supernovae. We expect millions of stars in the solar system and billions of galaxies, and that’s why machine learning is really essential.”
The data will be released each year to a select group of astronomers, and after another two years each dataset will be made publicly available for the global scientific community to work on, Higgs says.
There are four main areas of research that it is hoped the data will cover: creating an inventory of the solar system – including discovering several new celestial bodies and perhaps the hidden planet known as Planet Nine; mapping our entire galaxy; investigating a special category of objects called ‘transients’ that change position or brightness over time; and understanding the nature of dark matter.
“There are probably 10 different areas of science where I can tell you Rubin is going to do a great job,” Higgs says. “I think within a few months we will have more Type I supernovae than have ever been observed. Interstellar objects, we have two candidates now, but Rubin is going to take that from two to hopefully more than a few.
“There are so many fields where we can go from a few things to a statistically large sample of something, and the scientific impact of what that can do is enormous.”
“Revolutions are coming”
The astronomical community is very excited about the Vera Rubin Observatory, says David Kaiser, professor of physics and Germeshausen professor of history of science at the Massachusetts Institute of Technology. According to Kaiser, the telescope should help clarify long-standing questions about dark matter and dark energy – two of the most persistent and mysterious features of our universe.
“The Vera Rubin Observatory will allow astronomers to map the distribution of dark matter like never before, based on how dark matter bends the path of ordinary starlight – a process known as ‘gravitational lensing’,” explains Kaiser out. “Dark matter appears to be ubiquitous across the universe, but how exactly it has clumped or clustered over time remains difficult to quantify for large parts of the night sky,” he says, adding that collecting more data on the distribution of dark matter. the Vera Rubin Observatory could help astrophysicists discern its properties.
Another long-standing cosmic riddle that Rubin could solve is the hunt for Planet Nine. Konstantin Batygin, a professor of planetary sciences at the California Institute of Technology who has written several academic papers on the subject, says that the telescope not only offers “a real opportunity to directly detect Planet Nine, but even if the planet eludes direct observation, Detailed mapping of the dynamical architecture of the outer Solar System – in particular the orbital distribution of small bodies – will provide critical tests for the Planet Nine hypothesis.” In short, he adds, the Vera Rubin Observatory will revolutionize our understanding of the outer solar system, and is poised to be a “game-changer.”
Few astronomers aren’t excited about Rubin, says Kate Pattle, a lecturer at University College London’s department of physics and astronomy, because it will map space on scales ranging from the most local: tracking asteroids in near Earth our own solar system – to the largest, which maps the distribution of dark matter across the universe.
“Rubin will return to the same parts of the sky again and again, meaning it will break new ground in the study of astronomical transients – identifying variable stars, tracking supernova remnants as they decay, and observing very high-energy gamma rays. jet bursts and the variability of quasars, very distant, very active galaxies. In doing so, it will provide unprecedented insight into how our universe and the stars and galaxies within it evolve.”
According to Priyamvada Natarajan, professor of astronomy and physics at Yale University, the Rubin Observatory is poised to break records on many fronts and the entire astronomy community is waiting for its first flight. The research will provide data for a large number of scientific projects that will answer many fundamental open questions at once – ranging from the near to the distant universe, including not only a wealth of galaxies, clusters, quasars, supernovae and gamma-ray bursts. and other transients – “It will also sharpen our view of the solar system with a previously unparalleled inventory of near-Earth asteroids, objects from the Kuiper Belt (a region of icy objects beyond Neptune’s orbit ) – in short, there is something for everyone,” she says.
She adds that the most exciting find would be if the telescope revealed the true nature of dark matter – a discovery that would certainly please Vera Rubin.
“After all, it was her pioneering work on the detection of dark matter in spiral galaxies in the 1970s that kick-started this endeavor,” says Natarajan. “The prospects are tempting – and revolutions are certainly coming.”
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