See more at
FAIL Blog
"We have found a habitable environment," said John Grotzinger, project scientist for the Curiosity mission. "The water that was here was so benign and supportive of life that if a human had been on the planet back then, they could drink it."
Presently, astronomers only have a short period of observations to forecast the comet's path through the inner solar system and they know the probability of Mars "taking one for the celestial team" on Oct. 19, 2014, is small — in all likelihood the comet will fly by, creating a wonderful astronomical event for Earth and Mars-based observers alike.