Astronomers studying the Taurid meteor shower, which causes brilliant streaks of light in the night sky between late October and early November—sometimes called “Halloween fireballs”—suggest there may be an increased chance of cosmic impacts or airbursts from fireball ‘swarms’ in 2032 and 2036.
While spotting these potential threats has proven challenging, the researchers behind the study suggest that preparing for theoretical Halloween fireball swarms could help reduce property damage, serious injury, or even death from these explosive events.
“In movies about cosmic catastrophes, the comet or asteroid is always huge and would wipe out our entire planet, like the impact 66 million years ago that eliminated the dinosaurs,” Professor Mark Boslough from the University of New Mexico (UNM) told The Debrief, before adding that “the probability of that happening to us is extremely remote.”
Instead, the research professor and study’s lead author said most of the risk is from “small, airburst-sized objects,” such as those that caused the atmospheric explosions above Tunguska, Siberia, and Chelyabinsk, Russia, in 1908 and 2013, respectively.
“There are millions of times more of those than the number of remaining undiscovered dinosaur-killer-sized objects,” Boslough told The Debrief.
Although there are several sources of rocks and dust particles in space, the fragments that constitute the Halloween Fireballs come from the comet Encke, which left a trail of debris orbiting the sun. This orbit and Earth’s orbit intersect twice a year, with the first event occurring in June and the second occurring right around Halloween.
While the Spring event occurs during the day, making it difficult to spot all but the brightest fireballs in the daytime sky, the Halloween Fireballs occur at night, resulting in nature’s annual Fall aerial light show as smaller pieces burn up in the atmosphere. Still, some of the larger rocks can make it through the upper atmosphere before exploding above land in a brilliant flash. For example, the 1908 event that exploded above the remote region of Siberia was later determined to pack the explosive equivalent of a three to five-megaton bomb.
While not as large or explosive, the Chelyabinsk event is still rated at about half a kiloton. It was also witnessed by residents of the area who reported injuries, smashed windows, and other damage from the explosion. An analysis by Boslough and colleagues at Sandia Labs concluded that the 2013 event injured about 1,500 people and damaged more than 7,000 buildings.
While these events are still rare, Boslough’s latest analysis said there is evidence that the chances of these cosmic airbursts could be ‘enhanced’ due to these objects clumping together before intersecting with the Earth. Specifically, the researcher explained that as the Taurid meteor stream approaches Jupiter at regular intervals, the planet’s outsized gravitational pull could pull potential cosmic airburst space rocks closer together, resulting in “dense clusters.”
Although there is no direct evidence of swarms of fireballs on a collision course with Earth, the researcher said that previous impacts from the Taurid stream with the Moon showed some evidence of swarms “at the times the theory has predicted.”
Notably, Boslough told The Debrief that the recorded seismic lunar events, which occurred in 1975, came from objects “much smaller” than the objects that caused the cosmic airbursts above Russia, “and would not have penetrated deeply in Earth’s atmosphere or endangered anyone.”
Because the orbits of both the Earth and the Taurid shower are expected to come closer together in 2032 and again in 2036, the researcher suggests there are both increased risks and increased opportunities during both events. For example, a recently discovered object not part of the Taurid shower, known as 2024 YR4, may collide with the moon during the 2032 intersection. And although the risk of cosmic airbursts or even direct Earth impacts from fireballs is increased, Boslough told The Debrief that there are observatories that could offer some warning of a potentially dangerous event.
“The 2032 encounter will be this time of year (October-November) and the swarm will be coming from the night-time sky, so objects in it will be observable by many Earth-based telescopes that use visible light, including the Vera Rubin Observatory,” he explained.
Still, the researcher said that the small size and large volume of objects make spotting one before it collides with Earth’s atmosphere in 2032 rather remote. Instead, he suggests that observations taken during the 2032 event could reveal any potentially dangerous “Halloween fireball” swarms three and a half years before they occur, when objects in the swarm “will have completed a full orbit (about 3 1/3 years).” Then, the researcher said, any threat would make a close approach to the sun before heading back out toward Earth again from the other direction, “when the Earth is in a different part of its orbit at a different time of year (June).”
“The good thing is that if there is an object on a collision course for the June 2036 encounter (but missing the Earth in 2032), it would probably be discovered in the 2032 encounter,” Boslough told The Debrief. “The same swarm that approaches Earth from the nighttime sky in 2032 will approach from the daytime sky in 2036.”
Overall, the researchers noted that the risk of cosmic impacts or airbursts from swarms is still extremely low. As a result, Boslough said that even an enhanced risk due to swarms “means that the probability would still be low.”
When asked what steps people on the ground could take to prepare for potential cosmic impacts or airbursts from fireballs, Boslough told The Debrief that avoiding windows if there is a bright flash in the sky is recommended since the majority of injuries during the Chelyabinsk event came from shattered glass when people gathered at the windows to gawk at the explosion.
“Avoiding windows is the best advice anytime there is any kind of unexpected bright flash outside, because that indicates some kind of explosion (whether an accident, an act of war, or a cosmic airburst),” the professor explained. “The shock wave arrives after the light, sometimes minutes later if the explosion is far away.”
Boslough also told The Debrief that the “duck and cover” drills that were used during the Cold War are “exactly the methods that would reduce the number of casualties from a natural airburst, too.” Ultimately, the professor said that spotting any swarm of Halloween Fireballs before they burst in the atmosphere would offer even more protection beyond avoiding windows and ducking and covering. He specifically noted that if the proposed new infrared telescope (NEO Surveyor) is in operation, scientists could potentially offer much more warning time to prepare for potential impact or airburst events.
“If the asteroid is discovered in advance, then there will be warnings to evacuate, take cover, or shelter in place (depending on location and warning time, and size of the object),” Boslough told The Debrief.
The research was funded by NASA at UNM and in partnership with NNSA funding at Los Alamos National Laboratory (LANL) in the planetary defense program.
The study “2032 and 2036 risk enhancement from NEOs in the Taurid stream: Is there a significant coherent component to impact risk?” was published in Acta Astronautica, the proceedings of this year’s Planetary Defense Conference in Cape Town, South Africa.
Christopher Plain is a Science Fiction and Fantasy novelist and Head Science Writer at The Debrief. Follow and connect with him on X, learn about his books at plainfiction.com, or email him directly at christopher@thedebrief.org.