StellarHeat Transfer
You see heat transfer everyday in life. When a hot mug of coffee is placed in a room, the coffee matches the temperature of the room after a long time. Or when you touch a hot pan (don’t do this), the pan heats up your hand, causing discomfort. This can all be explained chemically through heat transfer. Particles in a warmer body have a higher average kinetic energy, or thermal energy, than those in a cooler body. As the warm and cool bodies are placed in contact, the particles in them collide, causing energy to be transferred from the warm to the cool body.
After a long enough time, the particles in the warm and cool body reach the same average kinetic energy, which is seen macroscopically as them reaching the same temperature. This is known as |thermal equilibrium|.