While we're keeping an eye out for Comets Lemmon (shouldn't they call it "Comet Lime," in view of its color?), PANSTARRS, and ISON here on Earth, Marvin the Martian has other worries.
A newly-discovered comet- C/2013-A1- may well hit Mars in October of next year.
Contrary to the scare-mongers, there was never much of a chance that PANSTARRS- which will come closest to Earth on Tuesday- would hit us.
But scoffing aside, this is a sobering reminder that comets do hit planets- remember Shoemaker-Levy 9?- and that Earth is actually a bigger target than Mars is.
Just because the cries of "Wolf!" have been wolf-less of late doesn't mean that it still might not happen again some day. Ask the dinosaurs what happened last time.