http://copernico.dm.unipi.it/~milani/resret/
Abstract:
The Earth passes very close to the orbit of the asteroid 1999 AN twice per
year, but whether or not this asteroid can have a close approach depends
upon the timing of its passage across the ecliptic plane.
The uncertainty of this timing grows with time: by 2027 it is days. Among the possible orbital solutions there are some that undergo a close approach in August 2027, but no impact is possible. However, the period of the asteroid may be perturbed in such a way that it returns to an approach to the Earth at either of the possible encounter points.
We have developed a theory which successfully predicts the 25 possible such returns up to 2040. We have also identified 6 more close approaches resulting from the cascade of successive returns.
None of these encounters can result in an impact, except one in August 2039: the probability that the true asteroid actually follows a collision course for that date is less than the probability of being hit by an undiscovered asteroid within any given day. Because of this extremely chaotic behaviour there is no way to predict all possible approaches for more than a few decades after any close encounter, but the orbit will remain dangerously close to the orbit of the Earth for about 600 years.
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# Max M Rasmussen, New Media Director http://www.normik.dk Denmark
# Private mailto:maxm@maxmcorp.dk http://www.maxmcorp.dk
$TheWorld =~ s/Microsoft Corporation//g;