New Study Eases Concerns Over Possible ‘Doomsday’ Asteroid Swarm
UMD Astronomer and Team Found Fewer Dangerous Space Rocks in Earth’s Neighborhood Than Expected
A nearby asteroid swarm is far less of a deep-space threat than previously thought, new UMD-led research has shown.
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Astronomers have good news about potentially hazardous asteroids lurking near our planet: There aren’t as many as we thought.
A team of researchers led by the University of Maryland surveyed a large expanse of sky to investigate a stream of space debris drifting near Earth called the Taurid swarm. Thought to be remnants that broke off of a large comet called Encke, the Taurids can be seen from Earth as highly visible meteor showers in October and November. This region has long intrigued astronomers due to its potential for harboring hidden, dangerous asteroids, but researchers could not confirm or disprove the existence of such hazards—until now.
The group’s findings were announced at the American Astronomical Society's Division for Planetary Sciences annual meeting on Monday. The team also included researchers from Poolesville High School in Maryland, the University of Western Ontario and the University of Washington, Seattle.
Photo by NASA/JPL-Caltech/Univ. of Minnesota
“We took advantage of a rare opportunity when this swarm of asteroids passed closer to Earth, allowing us to more efficiently search for objects that could pose a threat to our planet,” said Quanzhi Ye, who supervised the project and is an assistant research scientist in UMD’s Department of Astronomy. “Our findings suggest that the risk of being hit by a large asteroid in the Taurid swarm is much lower than we believed, which is great news for planetary defense.”
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Prior to this study, which used the Zwicky Transient Facility (ZTF) telescope, researchers speculated that the Taurid swarm contained a considerable number of large space rocks at least a kilometer in diameter that were left behind by a large object possibly up to 100 kilometers (62 miles) wide. Large objects can cause regional damage if they were to impact Earth, such as the Chelyabinsk asteroid that hit Russia and injured more than 1,600 people in 2013. Even larger objects can cause extinction-level events, such as the asteroid 10 or more kilometers in diameter that killed the dinosaurs over 66 million years ago.
The researchers found that its likely only a handful of large asteroids—perhaps nine to 14—are hiding in the swarm, Ye said.
“Judging from our findings, the parent object that originally created the swarm was probably closer to 10 kilometers in diameter rather than a massive 100-kilometer object,” he said. “While we still need to be vigilant about asteroid impacts, we can probably sleep better knowing these results.”
According to Ye, the Taurid swarm holds important clues about planetary evolution, especially due to its connection to the comet Encke. It has the one of the shortest orbital periods of known comets, taking just 3.3 years; Encke is also unusually large and dusty for a short-period comet (which orbit the sun in 200 or fewer years). Considering available evidence, scientists believe that Encke experienced significant fragmentation in the past—and may continue to fall apart similarly in the future.
“Studying the Taurid swarm helps us understand how small celestial bodies like comets and asteroids form and break apart over time,” Ye said. “Our research has implications not just for asteroid detection and planetary defense, but also for our broader understanding of solar system objects.”
While the study’s results are reassuring, the team believes that they also underscore the need for ongoing vigilance and improved detection capabilities. Using advanced facilities such as the ZTF telescope, which can efficiently conduct vast sky surveys and track potentially hazardous near-Earth objects, the researchers plan to conduct follow-up observations during the coming autumns.
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