Scientists and Hollywood producers alike have pondered the use of nuclear bombs as our savior in the event of a massive asteroid on a collision course with Earth.
With recent advancements, this concept may now be grounded in reality.
Researchers at Sandia National Laboratories, a key U.S. government facility known for ensuring the security of the nation’s nuclear arsenal, have performed the first comprehensive demonstration of nuclear-assisted planetary defense.
They documented, in nanosecond detail, how the intense radiation from a nuclear blast could vaporize one side of a nearby asteroid, potentially pushing it off its deadly trajectory.
The process envisioned works by rapidly heating the asteroid’s surface to tens of thousands of degrees, forming a blistering ball of gas that can shove the space rock away from its path toward Earth.
Dr. Nathan Moore, the study’s lead author, explained, “The vaporized material shoots off one side, pushing the asteroid in the opposite direction. It’s like turning the asteroid into its own rocket.”
The dire necessity for such measures is underscored by Earth’s own history.
Although significant asteroid impacts are rare, the event that caused the extinction of the dinosaurs 66 million years ago serves as a grim reminder of space rocks’ potential for devastation.
Even smaller meteors, like the one that exploded over Chelyabinsk, Russia, in 2013, demonstrated the destructive power by injuring over 1,200 people.
NASA’s Double Asteroid Redirection Test (DART) positively altered the orbit of the moonlet Dimorphos in 2022, proving the effectiveness of kinetic impact as a means of defense.
However, such methods require years of foresight to be effective.
Nuclear explosions, on the other hand, could provide a solution for larger asteroids and those that show up with little warning.
Unlike dramatic Hollywood depictions, this real-world approach doesn’t involve shooting directly at the asteroid.
Rather, it involves a standoff explosion that vaporizes part of the asteroid’s surface, leveraging Newton’s third law to redirect the remaining mass.
To test this theory, Moore and his team replicated a nuclear blast’s effects by using the world’s strongest lab radiation source, the Z machine.
They exposed pieces of a mock asteroid to intense X-ray pulses, observing how these pulses obliterated supports holding the material and vaporized its surface.
This method propelled pieces of the mock asteroid to speeds nearing 200 mph.
The study’s results, published in Nature Physics, suggest the strategy could work for asteroids up to 2.5 miles wide, assuming sufficient warning time.
However, the researchers acknowledge that scaling these results to full-size asteroids necessitates further study, a gap the European Space Agency’s upcoming Hera mission aims to fill by studying DART’s impact aftermath.
Despite the successful demonstration, there remains some skepticism.
Professor Gareth Collins from Imperial College highlighted the need for non-nuclear options like kinetic impactors, which are more technologically achievable.
Yet, Moore’s “spectacular” experiments suggest that when dealing with very large asteroids or short warning times, nuclear might be our most viable option.
As nations worldwide probe various planetary protection tactics, including China’s ongoing deflection experiments, this nuclear strategy stands as a promising, albeit last-resort, measure to protect our planet from catastrophic asteroid impacts.