The snarky answer would be to just leave this link https://en.m.wikipedia.org/wiki/Orbital_mechanics https://en.m.wikipedia.org/wiki/Orbital_mechanics. But to

The snarky answer would be to just leave this link https://en.m.wikipedia.org/wiki/Orbital_mechanics https://en.m.wikipedia.org/wiki/Orbital_mechanics. But to more fully answer the question look to https://en.m.wikipedia.org/wiki/Elliptic_orbit https://en.m.wikipedia.org/wiki/Elliptic_orbit Notice that the object with an eccentricity of 0.8 has a much faster speed as it approaches the mass it is orbiting. So, to extrapolate, objects with a high eccentricity will be moving much faster as their semi major axis decreases (as they get closer to the mass it is orbiting). Faster means less time to detect the object. Less time to detect the object means we have less time to react to the object. Less time means planet killer. And keep in mind the time periods we're talking about for some of these objects measure in the tens of thousands of years. So we don't really get a chance to record these objects for "next time".