 And now we get to the third and final way in which heat can go from one place to another, radiation. What's the basic idea here? Well, space is full of invisible electric and magnetic fields. Normally they don't do very much, unless you've got a big electromagnet nearby your electric field. But if you take some atoms and you jiggle them around, because they're hot, it turns out that actually makes these invisible electric and magnetic fields jiggle as well. And when you get jiggling electric and magnetic fields, ripples of jiggling fly through space, which are called electromagnetic waves. Also known as things like light, radio waves, x-rays, gamma rays, infrared ultraviolet. These are all electromagnetic waves, and they're all produced whenever atoms jiggle. And these wiggling electromagnetic fields can fly through space until they find some atom somewhere away. And when you apply a wiggling electric field to an atom, you make it jiggle too. And so, not only does everything emit electromagnetic waves, but when there's electromagnetic waves of any sort hit anything else, they make it jiggle too. So for example, the atoms in the surface of the sun are jiggling like crazy because they're about 6,000 degrees, and that causes them to glow, and this radiation is mostly visible light, mostly yellow light, and this yellow light flies through space. That's a big advantage of radiation you see. It can actually go right through a vacuum, which certainly can't happen with conduction or convection. And these jiggling electromagnetic waves, visible yellow light, comes and hits your skin as you sunbathe and makes your skin atoms jiggle faster and warms you up, and that's how the sun brings heat to the world. So it's incredibly useful.