If it hits Mars, it could help to terraform the planet. The CO2 ice caps would melt and heat the atmosphere. It would melt a significant amount of frozen water

If it hits Mars, it could help to terraform the planet. The CO2 ice caps would melt and heat the atmosphere. It would melt a significant amount of frozen water in the soil and thicken the Martian air with water vapor too. Wikipedia is predicting a 1 in 1250 chance of hitting Mars. Outgassing as the comet nears the sun could change its trajectory significantly also. http://en.wikipedia.org/wiki/C/2013_A1 http://en.wikipedia.org/wiki/C/2013_A1