Things that give off light often also give off heat. Heat is produced by mechanical and electrical machines, and any time one thing rubs against something else. When warmer things are put with cooler ones, the warm ones lose heat and the cool ones gain it until they are all at the same temperature. A warmer object can warm a cooler one by contact or at a distance. Some materials conduct heat much better than others.
Poor conductors can reduce heat loss.
Changes in speed or direction of motion are caused by forces. The greater the force is, the greater the change in motion will be. The more massive an object is, the less effect a given force will have. How fast things move differs greatly. Without touching them, a magnet pulls on all things made of iron and either pushes or pulls on other magnets.