Yes earth is magnetic. The chemicals present in the crust produce a magnetic effect . The geographical north pole is actually the magnetic south pole and vice-versa . This happens because of attraction between unlike poles.
For one, it helps block projectiles and keep some from getting to our atmosphere. It also holds the moon in place. And the last thing I can think of at the moment is that it helps us determine...
I saw a show on this topic. Every once in a while the sun shoots out solar flares, these are made out of the suns material and are dangerous, they also go pretty far. Occasionaly one heads straight...