Research Says Nuclear Blast Effective For Late-Stage Asteroid Impact

A new space study has revealed that using a nuclear disruption method is an effective solution in an emergency scenario where an asteroid is in the late stages of a collision course with Earth. When it comes to avoiding a potentially catastrophic asteroid impact, there are multiple theories that are currently being tested based on how much preparedness is needed and, of course, the size of the incoming celestial body. The kinetic deflection model, for example, proposes a small detonation on the asteroid surface to veer it off course and avoid an impact.

Another version of the strategy is sending a spacecraft into space and ramming it against the asteroid to knock it off course. NASA is actually testing this approach as part of its DART planetary defense project. The asteroid gravity tractor model proposes using a massive spacecraft that hovers over an asteroid and gravitationally interacts with it so that the asteroid is pushed into a non-threatening orbit. There’s also a tactic that involves using a focused solar beam to vaporize some material off the asteroid’s surface, a process that will create some thrust and deflect the asteroid from its collision path. However, a majority of the aforementioned solutions require a lot of time and preparation, which is where the disruption tactic sounds more effective.

Related: Massive NASA Deep Space Antenna Just Caught Its 1,000th Near-Earth Asteroid

But so far, the risk associated with disruption is that breaking up an asteroid into multiple small pieces might attract some fragments to Earth and cause smaller impacts. Now, a new study that employed an advanced impact simulation technique has revealed that a nuclear disruption technique can indeed save the Earth from an asteroid impact that pops up on the radar a little too late for preparations. Scientists used software called Spheral that modeled the nuclear destruction of an asteroid and then studied the gravitational trajectory of the fragments to see if they can safely fly past the Earth. The hydro simulations tested on at least five asteroids prove that nuclear disruption is a viable late-time method for averting an asteroid impact.

As part of the study, scientists virtually deployed a 1-Megaton-yield nuclear device that explodes a few meters away from a Bennu-shaped asteroid that is 100 meters across in size. To recall, Bennu is the same asteroid that has a 0.037 percent probability of making an impact with Earth in 2182. The team behind the latest study, which has been published in Acta Astronautica, says that if a calculated nuclear disruption is performed two months before the asteroid hits the Earth, 99.99 percent of the Asteroid’s mass will miss the Earth. The proposed disruption event is said to bring down the fraction of impact mass by a factor of 1,000 or more. And even if the asteroid is bigger, a nuclear disruption that is performed six months before the impact date will be effective enough that 99 percent of the broken fragments fly past Earth without posing any risk.

However, it is a daunting task to follow each broken fragment’s trajectory by studying its gravitational interactions with other fragments in the debris cloud, the Earth, and the Sun. Plus, there is still a small chance that some broken fragments after the nuclear disruption might enter the Earth’s atmosphere. Overall, the team concludes that nuclear disruption is still the most effective method to avert a late-time asteroid impact emergency, but kinetic methods should preferably be used if there is enough time to prepare. But asteroids come in all shapes and sizes, so more advanced simulations are needed to better assess the viability of a nuclear disruption event as the last resort.

Next: The Largest Comet Ever Detected Is Creeping Closer To Earth

Source: Lawrence Livermore National Laboratory

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