These electromagnetic waves can include UV waves, radio waves, microwaves and infrared waves, and other waves as well. So all objects on Earth and in space radiate heat or radiate energy. And that's because every single object has some temperature and zero Kelvin, the absolute zero temperature, is unattainable. So all objects vibrate or move to a certain extent, and therefore all objects at all times radiate energy. Okay? One cool thing about radiation, unlike convection or conduction, is that radiation can occur in the absence of molecules or in the absence of a physical barrier.