DEFENDING THE EARTH FROM LONG-PERIOD COMETS AND SNEAKY ASTEROIDS: SHORT TERM THREAT RESPONSE REQUIRES LONG TERM PREPARATION
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Comets, such as the recent Comet C/2013 A1 (Siding Spring) can impact terrestrial planets with very short warning times: for Siding Spring the time from discovery to closest approach to Mars (135,000 km) was less than 22 months. Short warning times are also po... ...
