Reported by ScienceDaily
A nuclear explosion could potentially protect Earth from an incoming asteroid by releasing powerful X-rays that heat its surface and push it onto a safer trajectory. However, new research suggests that the success of such a mission could depend heavily on which side of the asteroid receives the blast.
Unlike the smooth, round objects often used in computer simulations, real asteroids have uneven surfaces and irregular shapes. Those differences can dramatically influence how an asteroid moves when exposed to intense radiation.
A new study published in Icarus found that changing the direction of an X-ray burst could produce vastly different results, even when targeting the same asteroid. In one simulation, the asteroid's speed changed by 3.9 millimeters per second when irradiated from one direction, compared with only 0.8 millimeters per second from another. That represents a nearly fivefold difference in deflection velocity, the change in the asteroid's forward speed caused by the burst.
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"We expected aim to matter," said Nathan Moore, a physicist at Sandia National Laboratories who led the research. "What surprised us was how much."
The effects on an asteroid's rotation could be even more dramatic. For another simulated asteroid, the change in how quickly it spun varied by a factor of 17 depending on the direction of the X-rays.
These findings suggest that understanding an asteroid's shape and carefully selecting where to direct a nuclear blast could be essential to protecting Earth from a future impact.
The research received funding through Sandia's Laboratory Directed Research and Development program.
To investigate how different asteroid shapes respond to nuclear blasts, Moore and his colleagues developed what they describe as the most accurate asteroid deflection model yet.
Earlier computer models faced a major limitation. Researchers typically had to choose between representing an asteroid's complex shape and performing highly detailed calculations of the physical forces involved. Combining both approaches demanded more computing power than was practical.
The new system overcomes that obstacle, allowing scientists to study realistic asteroid shapes while maintaining the precision needed to calculate their response to an X-ray burst. The result is the most detailed simulation of asteroid…