Northeastern University astrophysicist Jonathan C. Blazek knew to expect stunning views of galaxies when the new Vera C. Rubin Observatory in Chile released its first images of the night sky on June 23.
And the sights were extraordinary. With a telescope as wide as a tennis court and the world’s largest digital camera, the observatory captured more than 10 million galaxies in one image.
What surprised Blazek, an expert in observational and theoretical astronomy, was the observatory’s detection of 2,104 new asteroids, including seven near-Earth objects.
“Seeing those asteroids was amazing. In several nights, they discovered thousands of asteroids that have never been seen before. I was not expecting that,” he says.
Asteroid detection is just part of the observatory’s overall mission, but it can play an important role in planetary defense, Blazek says.
“The fact that we’ve been around for a long time as a species means we don’t get hit by big things that often,” he says. “But it’s possible, and this is by far the best tool we’ve ever had to find asteroids that might be a problem.”
“There’s also an intermediate category of objects which are not necessarily planet killers” but could still cause destruction, Blazek says. He cites the example of the Tunguska asteroid that exploded over a sparsely populated area in Siberia on June 30, 1908, flattening millions of trees and setting off massive forest fires.
“If that happened now in a populated area, you would want to have some warning to get people out of the way,” or to use asteroid-redirecting technology, he says. “This gives you that warning.”
Funded by the National Science Foundation and Department of Energy, the Rubin Observatory is conducting the Legacy Survey of Space and Time (LSST) that will capture images of the Southern Hemisphere’s entire sky every three to four nights for 10 years, creating a time-lapse movie of the universe.
The unprecedented amount of data collected is expected to yield clues about the formation of the Milky Way as well as a map of the mysterious dark matter that, with dark energy, makes up 95% of the universe, says Blazek, who is conducting research as part of the LSST’s Dark Energy Science Collaboration.
He says the Rubin telescope’s wide field of view and SUV-sized camera create color images of big chunks of sky by combining a series of short, 30-second exposures.
The telescope “is looking at the same patch of sky many times and can go and see faint objects,” Blazek says.
He says that when searching for asteroids in the past, astronomers had to choose from either a telescope with a small field of view that can find faint objects — which in the case of asteroids tend to zoom out of frame quickly — or one that “has a wide field of view but can only find fairly bright objects or things that require a longer exposure time.”
“When you have one of the world’s largest telescopes and the world’s largest digital camera (working) together, you can get all these things at once. That’s really what you need to find asteroids that are not huge, and that’s why they found so many so quickly.”
Near-Earth objects are asteroids, comets and other objects whose orbits bring them into proximity with the Earth’s orbit, raising the potential, however remote, of a collision.
The asteroid known as the Chicxulub impactor that killed the dinosaurs 66 million years ago was six miles wide.
The Rubin observatory expects to identify 90% of potentially hazardous asteroids over 140 meters, or about 153 yards, Blazek says.
In total, the LSST says it will discover millions of new asteroids, large and small, in the first one to two years of operation. Scientists currently know of 1.45 million asteroids, most of which are found in a wide zone between Mars and Jupiter.
“In general, it will provide a much better census of things that are close to us, things that are worth tracking,” says Blazek, who belongs to a group of scientists and professors called Rubin in Boston that meets about twice a year.
He says anyone with any interest in the world around them should take a look at the images and video from the Rubin Observatory’s test run and keep tabs on developments once the LSST is fully operational this fall.
“It’s the difference between someone telling you something’s beautiful and seeing that something is beautiful,” Blazek says.