A nuclear blast could save Earth from an asteroid, but there's a catch
A nuclear explosion might save Earth from a deadly asteroid, but new research suggests that hitting the wrong side could make the difference between success and disaster. Scientists found that an asteroid's irregular shape can dramatically affect how it responds to an X-ray blast, with deflection effectiveness varying nearly fivefold depending on the angle.
Key points
- A new study found the direction of a nuclear X-ray burst can nearly quintuple an asteroid's deflection velocity.
- Simulated spin changes varied by a factor of 17 depending on blast direction.
- The new model is over 1,600 times faster than earlier approaches, its lead researcher said.
A nuclear explosion could push a threatening asteroid off course by releasing X-rays that heat its surface, but new research suggests the outcome depends heavily on which side of the asteroid is hit. The study, published in Icarus, found that changing the direction of an X-ray burst can produce vastly different results even on the same asteroid.
In one simulation, an asteroid's speed changed by 3.9 millimeters per second when irradiated from one direction, compared with 0.8 millimeters per second from another, a nearly fivefold difference. For another simulated asteroid, the change in spin rate varied by a factor of 17 depending on blast direction.
Why shape matters
Real asteroids have uneven surfaces and irregular shapes, unlike the smooth spheres often used in computer simulations, and these differences affect how they respond to intense radiation. The team, led by Sandia National Laboratories physicist Nathan Moore, developed what they describe as the most accurate asteroid deflection model yet, combining two simulation systems used at Sandia.
Moore said the new algorithm is "over 1,600 times faster" than earlier models, which could not handle both complex shapes and detailed force calculations at once.
Pick the right side and you win. Guess wrong and it could be a bad day.
— Nathan Moore
Remaining limits
The simulations cannot yet predict every consequence of a nuclear blast. Moore said the model only considers breakup of rocks on the surface and cannot accurately predict breakup of an entire asteroid body.
The software also needs accurate shape data from every direction, which might not be available in time if an asteroid were found on a collision course with Earth. Delivering and positioning a nuclear device at the right location would require extraordinary precision.
