Is my understanding of electromagnetic waves correct

My understanding of electromagnetic waves is that earths core has charged particles, so there is an electric field, when those charged particles move they will create a magnetic field and earth has a magnetic field. Electromagnetic waves are caused by electric and magnetic waves, so sense the earth supports both of these, electromagnetic waves can exist in the air, am I correct, if not please tell me how electromagneitc waves work. I have asked why don't electromagnetic waves need a vaccum to move through but the answer are to complicated , so if your going to answer please answer as if you were talking to your fiend who knows nothing about physics, please do not anwers as if you were talking to another physicist.