HOW CAN WE STOP THE ASTERIOD FROM HITING EARTH !!!

how do we do to stop the rock hiting our earth  nasa said it will take a couple of years or so before we can save our planet from asteriods and comets . also asteriod 2012 d4 just miss earth late friday afternoon at 2pm est local time nasa said we are lucky today that didnt hit us if did it takes a little damage ,

nasa said that the next asteriod or comet wont hit our planet till year 2029 in april ,