What would you do with the world’s biggest camera? Take the greatest Instagram selfie ever? Capture a stunning wildlife scene? What about probing the very structure of the universe ?
That’s what astronomers at the Vera Rubin Observatory in Chile have opted for. Under construction at the peak of the 9,000-foot-tall Cerro Pachón in the Chilean Andes, the observatory will sport the largest digital camera in history, a pristine telescope mirror as wide as a London bus, and a fast-moving mount to study the universe like never before.
“The major strength of this technology is to see faint objects and the dynamic universe—things that are changing,” says Sandrine Thomas, deputy director of Rubin Observatory Construction. “That gives us a lot of information about the beginning of the universe, galaxies, and objects in our own solar system.” Construction on Rubin—named for the late astronomer Vera Rubin, who pioneered work on dark matter—is set to be completed next year, when it will take its “first photons,” says Thomas, referring to its initial glimpse of the universe. In 2025, it will then begin work on its primary goal, the Legacy Survey of Space and Time, for which it will spend a decade taking exquisitely detailed images of the heavens.
Over those 10 years, the telescope will take 700 pictures a night, totaling some 20 terabytes of data every day. After a decade, it will have captured 800 pictures of each portion of the southern sky. To do this, it’s been designed to move quickly, switching between targets in just five seconds, instead of the minutes required by other telescopes. There are 189 charge-coupled device sensors in the telescope’s camera, each sporting a 4,096 x 4,096 pixel sensor, which will snap an image of the light collected in the 8.4-meter-wide primary image to create a 3.2-gigapixel snapshot of the universe.
No survey of the sky has ever deployed such a fast-moving telescope coupled with such a powerful camera, giving Rubin an unparalleled ability to study the universe. Over 10 years, the telescope is expected to snap some 40 billion cosmic objects, including billions of galaxies. This will enable astronomers to learn more about dark matter, the mysterious, invisible substance that accounts for 85 percent of all matter but that we can only discern from the way it distorts the appearance of galaxies.
Astronomers like Rachel Mandelbaum at Carnegie Mellon University in Pennsylvania will use Rubin’s galaxy images to study an effect called weak gravitational lensing, where massive objects “distort spacetime and change the paths that light rays would have taken,” she says. “Dark matter doesn’t interact with light, but it has a gravitational effect, so weak lensing is a great way to map out the distribution of dark matter in the universe.”
Rubin is particularly well-suited to this technique because of its wide field of view, which makes each snapshot it takes as wide as seven full moons. With this capability, it can do much more than explore the distribution of dark matter. The telescope will image millions of asteroids in our solar system, many undiscovered, and perhaps confirm or deny the existence of “Planet Nine”—a hidden planet that’s theorized to be lurking at the edge of the solar system. Rubin will also provide rapid alerts on supernovae exploding throughout the cosmos, as well as charting an accurate map of stars in our own Milky Way.
Construction will have taken nearly a decade by the time it’s completed, but results from the telescope will be timeless. “It’s extremely exciting,” says Thomas, “and stressful at the same time, because we want to make sure that it all works.” Now, the end is in sight. Space and time await.
This article first appeared in the November/December 2023 issue of WIRED UK.
This article was originally published by WIRED UK
