Rubin Tracks Skyscraper-Size Asteroids, Failed Supernovas, and Interstellar Visitors

Once the full survey begins this summer, Rubin is expected to produce 7 million alerts and 20 terabytes of data a night.

For just one example of how this firehose of data is expected to transform our understanding of the cosmos, consider supernovas, the brilliant death throes of exhausted stars.

Back in the late 1990s, two teams of astronomers used observations of under 100 “Type Ia” supernovas to make a revolutionary discovery about our universe: Its expansion is accelerating due to a still-mysterious force called dark energy. Once Rubin is fully up and running, researchers expect to find 250,000 such supernovas in a year.

Scientists hope that Rubin’s supernova data can help resolve the Hubble tension, the observation that the recent universe appears to be expanding faster than predicted when compared to the early universe. “We want to collect huge samples of Type Ia supernovae to probe this acceleration in much greater detail,” Smartt said.

Smartt is also interested in finding failed supernovas, which occur when stars collapse in on themselves rather than exploding outward. They might have their origins, paradoxically, in the most massive stars. In February 2026, scientists pinpointed a possible candidate in the Andromeda galaxy.

Rubin, with the exquisite detail of its images, is well placed to find these types of events, in which stars disappear in explosions that can be too faint for other surveys to see. “It goes down 100 times fainter than other sky surveys,” Smartt said.

Visitors From Afar

Rubin can also be used to track interesting and unusual objects passing through our solar system. It’s traditionally been difficult to catch such speedy travelers, at least without a survey that can pick out very faint objects at a rapid pace. Scientists have only ever observed three such interstellar objects — asteroids and comets that were ejected from other stars and fired into our vicinity — giving us insight into material from other solar systems. Rubin has already proved its ability to spot them.

Scientists announced the observation of an interstellar comet called 3I/ATLAS on July 1, 2025. They detected it without Rubin, via a network of four other telescopes that forms the Asteroid Terrestrial-Impact Last Alert System (ATLAS), which usually finds objects formed nearby.

Other astronomers followed up by looking through Rubin’s initial data and discovered that the observatory had also detected 3I/ATLAS, 10 days earlier. If a similar visitor from afar appears in Rubin’s data during the survey, astronomers will receive an alert.

Scientists don’t know exactly how many more interstellar objects Rubin will find, but they expect it to find at least some. “It could be five to 500,” depending on how often these objects are ejected from their home systems, said Rosemary Dorsey, an astrophysicist at the University of Helsinki in Finland. “I am optimistic there will be some, but if there aren’t, then that is a really interesting problem.”

Going the Distance

One way that astronomers determine the distance to an object in space is by studying its light. As light makes its way toward Earth while traveling through the expanding universe, it shifts toward the red side of the electromagnetic spectrum. The higher the redshift, the more stretched the light is, and the farther its source is from Earth.

Rubin’s preview data allowed scientists to test how well it could measure this light via a technique called photometric redshift, which will let it map galaxies across the universe to probe dark energy and dark matter. “The preview data tells us how accurate those photometric redshifts are going to be,” said Kristen Dage, an astronomer at Curtin University. Rubin performed at least as well as other cutting-edge telescopes, Dage said, but it will measure the redshift of many more galaxies, about 4 billion of the 20 billion galaxies it will find.

Dage expects that this data will also help scientists study fast radio bursts (FRBs), bright, unexplained flashes of radio waves in the sky possibly linked to highly magnetized stars called magnetars. While Rubin cannot detect radio waves, photometric redshift data will help scientists work out the distances to FRBs if they can be sourced to a host galaxy Rubin can measure, which could help scientists determine the processes that trigger them.

All of this is just a smattering of what scientists are hoping to explore when Rubin comes online. With it, a new era of astronomy is set to begin.

“Rubin is going to be putting out so much data, so many alerts every night, that everybody’s going to struggle to keep up with [the] information,” Frazer said — a challenge, but a delightful problem to have.