Id have thought one of the major changes would be the gravitation point where the earth and moon rotate around? maybe this point would now be outside the earth body... either way it would change the way the moon rotates around us and in so changing the orbit around the sun...
i am no astro physicist but this make sense to me
and when you say half, i automatically thought layers from the outside. that would leave the molten core exposed to space cause i dont think there would be any ozone layer or atmosphere or anything....
gah! my head hurts