Today in class we started talking about waves. I understand waves to be energy. This makes sense to me when thinking about sound waves, because the energy can travel from one particle to the next to travel; but I don't understand how things like electromagnetic waves can travel through a vacuum. The wave's energy can't be passed from one particle to the next because there are no particles in a vacuum and I don't understand how the energy could move because well, it's energy. I accept that it travels because otherwise we wouldn't be able to see the planets and Martians and what-not. Is this something to do with E=mc2? Do we even know the answer? This isn't a homework question, just me questioning things, but it's still related to school so I'm sorry if this is the wrong place.