Halloween fireballs could signal increased risk of cosmic impact or airborne explosion in 2032 and 2036, research suggests

Every year, the Taurids meteor shower lights up the night sky from late October to early November. Sometimes called “Halloween fireballs,” they are named after the constellation Taurus, the bull, from which the meteors appear to radiate. The shower is best viewed from dark places.

In New Mexico, where wide open spaces and low light pollution offer some of the clearest skies in the country, astronomers have a front-row seat to witness the spectacle.

Meteors are flashes and streaks of light that appear when dust, pebbles, and rocks burn as they enter Earth’s atmosphere. These fragments come from comet Encke, which left a trail of debris orbiting the sun.

Twice a year this stream crosses Earth’s orbit: once around Halloween, when the Taurides are visible at night, and again in June, during the day. June meteors, known as beta-taurids, can only be seen in the daytime sky if they are exceptionally bright fireballs.

But what would happen if much larger Taurids got a little too close to Earth?

New research led by Research Professor Mark Boslough, published in a special issue of Acta AstronautiqueThe proceedings of this year’s Planetary Defense Conference in Cape Town, South Africa, explore this idea.

The research titled “Enhanced 2032 and 2036 Risks from Tauride Stream NEOs: Is There a Significant Consistent Element to Impact Risk? » explores risk assessment for planetary defense.

“Planetary defense is a multidisciplinary, internationally coordinated effort to protect the Earth and its inhabitants from the impacts of near-Earth objects (NEOs),” Boslough explained.

“This requires surveys to discover and track near-Earth objects, campaigns to characterize which ones are dangerous, modeling efforts to understand and predict impact effects and associated consequences, and mitigation through impact avoidance and/or civil protection.”

A near-Earth object, or NEO, is an asteroid, comet or fragment whose orbit approaches or may cross the path of the Earth around the sun. These objects have the potential to collide with our planet, but only if their orbit crosses that of Earth and they arrive there at exactly the same time.

Small particles, such as the dust and rocks that create the Taurid “Halloween fireballs,” regularly enter our atmosphere. Larger objects, like those responsible for the Chelyabinsk and Tunguska meteor events, strike much less often.

Mitigation requires developing means to deflect or disperse an object on a collision course with sufficient warning, as well as planning for emergency responses in the event of unexpected or unavoidable impacts.

The research incorporated recently published data from observational campaigns associated with the Tauride Stream. Researchers have found that the risk from airburst-sized near-Earth objects (NEOs), small enough to explode in the atmosphere instead of hitting the ground, could be greater than currently estimated. Likewise, researchers have also investigated the possibility of a Taurid Resonant Swarm (TRS).

“The resonant swarm is theoretical, but there is evidence that a sparse swarm of small objects exists, as bright fireballs and seismic signatures of impacts on the moon have been observed at times that theory predicted,” Boslough explained.

Objects in the Taurid Current orbit the sun seven times for every two orbits of Jupiter. This cycle, called resonance, means that part of the flow approaches Jupiter at regular intervals. Because Jupiter is the largest planet in the solar system, its strong gravity can bring these objects together, creating dense clusters. It’s a bit like a prospector panning for gold: spinning the pan at just the right pace so the particles gather in one place.

The results suggest that if a Taurid swarm exists, it will pass near Earth in 2032 and 2036. During this time, Earth could experience a higher impact risk.

“Our conclusions are that we have the technology to test the Taurid resonant swarm using existing telescopes for targeted surveys of the sky in 2032 and 2036, when the hypothetical swarm will come very close,” Boslough said.

According to the researchers, in 2032 and 2036, objects in a hypothetical Taurid swarm could be observable, and the risk from near-Earth objects the size of an airburst could be greater than currently estimated. A concentration of larger objects (the size of Chelyabinsk or Tunguska) in a swarm would be observable by telescopes, if they exist, but only after missing Earth and receding into the night sky.

Boslough’s airburst models during his time at Sandia National Laboratories (SNL) explored the Chelyabinsk explosion and estimated that the asteroid was approximately 60 feet in diameter and had an explosive power of approximately half a megaton (TNT equivalent).

Likewise, the Tunguska was probably about 10 times more powerful (3-5 megatons), also based on Boslough’s SNL analysis.

“If we discover the objects with sufficient warning time, then we can take steps to reduce or eliminate the risk. If the new infrared telescope (NEO Surveyor) is operational, we can potentially have a much longer warning time,” he said.

Boslough suggests that it is important for citizens to be aware of various geohazards, including weather, fires, earthquakes and volcanoes, and to put them into perspective and be prepared to take action.

“Asteroid impacts represent a small but significant risk, and New Mexico National Laboratories have some of the best minds working on this problem,” he said.

One of the main lessons of the Chelyabinsk event is that most injuries were caused by broken glass as people rushed to windows to watch the bright flash in the sky. If a similar event were to occur in New Mexico, it would likely be the leading cause of injury. Experts say the public can learn from Chelyabinsk and stay away from windows and avoid looking directly at the explosion.

The 2032 passage of the hypothetical swarm will arrive on the night side of the Earth. Boslough says the likelihood of an air strike or explosion could be higher than average, if the significant concentration assumption is correct.

Boslough explains that daytime fireballs exist, but they have to be extremely bright to compete with the sun. A concentration of objects in a swarm (if it exists) would be observable by telescopes after missing Earth and receding into the night.

“The average probability is extremely low, so even an increased risk means the probability would still be low. The swarm will come from the direction of the sun in 2036, so the fireballs will not be visible in our blue sky unless they are extremely bright,” he explained.

The Magdelena Ridge Observatory near Socorro is involved in the observation portion of planetary defense, and SNL and LANL both have active planetary defense programs. As the university and national laboratories continue their research into TRS, Boslough cautions the public about the origins of its information.

“A lot of misinformation and mythologies about this have been spread on social media, online sources and sensational TV shows. These media outlets give the public a false impression about near-Earth objects, impacts and airbursts, and what we can do to reduce the risks,” he said.

Boslough has also been active in debunking this misinformation. His published research was instrumental in a journal’s decision to retract, due to the authors’ misunderstanding of the phenomena and evidence of aerial explosions, a highly publicized claim that an ancient city in Jordan was destroyed by an aerial explosion the size of Tunguska.

He also co-authored a comprehensive refutation of the fringe idea that the Taurid swarm was responsible for a climate catastrophe 12,900 years ago.

Would you like to see the Taurids spectacle up close soon? Boslough says there are a few opportunities to see, including on Halloween night after 2 a.m. They should be visible when the moon is not in the sky. A few days after the next full moon on November 5, the Taurid spectacle should be visible in the sky in the evening before moonrise.