Many asteroids survive violent plunges into Earth’s atmosphere. If they’re big enough, they can be incredibly destructive, like the 60-foot-tall Chelyabinsk meteor that exploded in Russia’s southern Urals region in 2013, releasing an explosion with 30 times the energy of the atomic bomb dropped on Hiroshima.
If a larger space rock threatens humanity, we’ll have to get creative to prevent it from colliding with our planet. Given the many uncertainties involved, crashing a spacecraft into it like a billiard ball to change its path — as NASA will do with its Double Asteroid Redirect Test (DART) proof-of-concept mission in 2022 — may not always be feasible.
In a new paper published in the journal nature communicationsan international team of researchers – including scientists from CERN and the University of Oxford – revisited the idea of ​​using a nuclear warhead to blow up an incoming asteroid.
There are intuitive concerns. What if asteroids shattered, turning cosmic sniper shots into shotgun blasts of debris raining down on our planet?
But the team used CERN’s Super Proton Synchrotron (SPS) to study how asteroid materials respond to varying degrees of physical stress, including large-scale simulations of nuclear deflection, and found that the space rock is surprisingly resilient.
“Planetary defense represents a scientific challenge,” Karl-Georg Schlesinger, co-founder of Outer Solar System Company (OuSoCo), a nuclear deflection startup working with scientists, said in a statement. “The world must be able to execute nuclear deflection missions with confidence, but without real-world testing in advance.”
In one experiment, the team exposed metal-rich meteorite samples to 27 short, intense proton beam pulses at CERN’s HiRadMat facility. The research team then moved the meteorite to the ISIS neutron and muon source at the Rutherford Appleton Laboratory in the UK to analyze changes in its internal structure at a microscopic level.
To their surprise, “the material became stronger, showed an increase in yield strength, and exhibited self-stabilizing damping behavior,” explains OuSoCo co-founder Melanie Bochmann.
This discovery could have major implications for how we approach asteroid redirection efforts in the future.
“Our experiments show that, at least for metal-rich asteroid materials, it is possible to use larger devices than previously thought without causing catastrophic damage to the asteroid,” Bochmann said. “This leaves an emergency option open for situations involving very large objects or very short warning times, where non-nuclear methods are insufficient and current models may assume that debris will limit the size of available devices.”
Fortunately, researchers will soon have more data to work with. Both NASA and the European Space Agency plan to study Apophis, a massive asteroid about 1,000 to 1,500 feet wide that is expected to pass very close to Earth in April 2029, closer than many geostationary satellites that are only 20,000 miles away.
“Next, we plan to study more complex rocky asteroid materials,” the researchers said in a statement. “One example is a class of meteorites called olivines, which consist of a metallic matrix similar to the meteorite materials we have already studied, with magnesium-rich crystals up to centimeters in size embedded inside.”
Upcoming research could also have fascinating implications beyond asteroid redirection.
“Because these objects are thought to have originated at the core-mantle boundary of early planetesimals,” they added, “such experiments could also provide valuable insights into the planet formation process.”
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