Part 3/5:
The core approach to planetary defense hinges on understanding asteroid orbits with precision. Scientists and engineers aim to identify objects on potentially hazardous trajectories and determine how their paths might be altered—should a collision be imminent. The primary goal is to modify the asteroid's orbit just enough so that it safely misses Earth, ideally years or even decades in advance.
One effective method to achieve this is by changing the asteroid’s velocity slightly. For example, if a 20 or 30-year window exists before a predicted impact, shifting the asteroid's speed by a mere millimeter per second could suffice to avoid disaster entirely. This incremental change, accumulated over time, results in a significant deviation from the original course, ensuring Earth remains safe.