Frank Daivs, who contributed a lot of words and computer jiggling to the Tall Bloke's Talk Shop debate on the February Chelyabinsk meteor (over Russia) that continued well into August, has now cast his somewhat beady eye at several comets about to visit the inner solar system (late 2013 and 2014). We are in for a treat, it seems, as he begins by looking at two of them, Comets ISON and Siding Spring, and then he realised there were another two on the way, comets Lovejoy and Encke – see http://cfrankdavis.wordpress.com/2013/09/20/9695/ and http://cfrankdavis.wordpress.com/2013/10/06/three-comets/
Comet ISON is in the vicinity of Mars right now and is due to reach perihelion on the 28th November, before heading back into deep space. The Earth will come within 3.5 million km on it initial journey – and it may not survive the encounter with the Sun.
Comet Siding Spring comes close to Mars in October of 2014 – next year. It will come so close that Mars will sail through its coma – what will happen? The plasma discharge theory of comets is about to be tested.
Comet Lovejoy willbe visible near Mars as ISON is on its way out.
Comet Encke is coming through too – just short of ISON.