When you cast this spell, choose an object within close range that has combined hardness and hit points no greater than five times your caster level. Until that object is destroyed, the affected area loses line of sight to it, the affected area loses line of effect to it, or it comes within 10' of the area, the area cannot be entered or exited. While impervious to entry or exit, it is impossible for anything to cross the boundary, and teleportation or planar travel into or out of the area is impossible as well.