Another comet, Siding Spring, is going to pass close enough to Mars on 19 October this fall that some say it's coma will envelope Mars and there is a slight possibility of impact; then there is its debris field for Mars to contend with.
18 posted on 02/27/2014 7:51:51 PM PST by Errant
(Surround yourself with intelligent and industrious people who help and support each other.)