CIERA Postdoc Shanika Galaudage and graduate student Jacob Sprague answer space questions at the Ask A Scientist table.
On Friday, October 3, 2025, a record-breaking audience of 350 filled Northwestern’s Ryan Auditorium for the Annual Public Lecture hosted by the Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA). This year’s speaker, Professor Christopher Stubbs of Harvard University, delivered a compelling talk titled “A New Eye on the Universe Opens—The Vera C. Rubin Observatory,” chronicling the decades-long effort to bring one of the most ambitious astronomical observatories ever built to first light.
Located high in the Chilean Andes, the Rubin Observatory is equipped with a 3,200-megapixel camera—one of the largest digital imaging devices in the world. In June, the telescope captured and released its first scientific images, opening the door to an unprecedented view of the universe.
“Chris has been deeply engaged with the Rubin Observatory all the way from its beginning going back 30 years,” said Vicky Kalogera, the Daniel I. Linzer Distinguished University Professor and Director of CIERA and the NSF-Simons AI Institute for the Sky. “In fact, he spent the past year in Chile as the project was coming up to first light, taking the first observational data. He was also heavily involved with the last stages of engineering.”
Stubbs, an experimental physicist whose work spans particle physics, gravitation, and cosmology, played key roles in the search for dark matter and was a member of the team that discovered the accelerating expansion of the universe.
Over the next decade, the Rubin Observatory will scan the entire southern sky repeatedly, producing a 10-year time-lapse movie of the universe at unmatched resolution and depth. 
“The goal of this observatory is to take sequential images of the entire southern sky sweeping back and forth,” Stubbs explained, “and take a ten-year-long time-lapse image to unprecedented depths and find really faint objects.”
The telescope is named after pioneering astronomer Vera Rubin, who in the 1970s provided crucial evidence for the existence of dark matter. “It’s named after Vera Rubin, I think, entirely appropriately,” Stubbs said. “She really showed the physics community how little we understand about the universe that we inhabit.”
In his lecture, Stubbs walked the audience through the 13.8-billion-year history of the cosmos, highlighting how quantum fluctuations in the early universe seeded the formation of stars and galaxies. He then turned to one of the most surprising discoveries in modern physics: that the universe’s expansion is accelerating, driven by a mysterious force known as dark energy.
“There’s a tension between the gravitational pull of dark matter, which promotes the growth of structure, and this repulsive effect of dark energy,” Stubbs said.
Closer to home, the Rubin Observatory is already making a mark. Its camera is sensitive enough to detect subtle motions of stars within our own galaxy—capturing the sky not as a fixed tableau, but as a dynamic, evolving scene.
Within its first week of observations, the telescope discovered more than 2,000 previously unknown asteroids in the asteroid belt between Mars and Jupiter.
“There is some likelihood that there’s an asteroid out there that has our zip code on it,” Stubbs quipped. Spotting potentially hazardous objects early is one of the observatory’s key missions.
Beyond asteroids, the Rubin data will help scientists study galaxy clusters, variable stars, and Type Ia supernovae—cosmic beacons essential for measuring the expansion of the universe.
CIERA graduate students (from left to right) Nathalie Korhonen Cuestas, Gideon McFarland, and Shafaq Elahi welcome visitors.
Precision is baked into the observatory’s design. Stubbs described a custom-built tunable laser system used to calibrate the telescope’s sensitivity across different wavelengths, and an auxiliary telescope that monitors atmospheric conditions in real time.
“It was a rather jubilant moment when the dang thing worked,” he said.
The project has not been without its engineering challenges—from quirky detector behavior to puzzling image artifacts like the so-called “angel wings.” But for Stubbs, these are simply part of the scientific process.
“You iteratively identify and solve problems,” he said. “There’s no showstopper problem here.”
One of Stubbs’ early concerns was that the scientific community might not rally around the observatory. “I had this unappreciated, deep fear in my heart that we would build this thing and nobody would care,” he admitted. “That has not turned out to be a problem.”
Since the release of the first datasets, researchers—and citizen scientists—have quickly gotten to work. The Rubin team encourages public engagement, offering open access to all data. “There’s no proprietary data, period,” Stubbs emphasized.
“The data flow right out to everybody—K through 12, all universities, and data-entitled institutions.”
CIERA Education and Outreach Coordinator James Schottelkotte, CIERA Assistant Director Tarraneh Eftekhari, Harvard’s Christopher Stubbs, CIERA Director Vicky Kalogera and CIERA Board of Visitors Member Burt Fujishima.
Stubbs also spoke about the growing role of artificial intelligence in Rubin operations. From generating real-time plots to classifying supernovae, AI tools—especially those powered by large language models—are streamlining discovery.
“Could we have written code to do that? Yes,” he said. “It would have just taken 50 times longer.”
As the Rubin Observatory prepares for full survey operations in late 2025, Stubbs sees it as a symbol of what large-scale, collaborative science can achieve.
“It’s going to completely change the way we do our business,” he said. “I think you should be proud of that investment. It’s going to turn out to be just a truly extraordinary thing.”
A recording of the lecture can be found on CIERA’s YouTube.
Story by Lisa La Vallee
Photo Credits: James Schottelkotte (feature image), Lisa La Vallee (other story images)