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.
"We expected aim to matter," said Nathan Moore, a physicist at Sandia National Laboratories who led the research. "What surprised us was how much."
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