Does anybody have any thoughts on why atoms that are warm need to radiate heat in order to stop vibrating or bond back together? The obvious example is the thermos. That is a thermos has the hot liquid contained in a glass container with a mirrored surface towards the inside and then a vacuum around that. Why do the vibrating atoms need a reflective surface? Is this so that they can see how pretty they are? Why does the vacuum transport heat energy at a slower rate and not a faster rate than having air around the glass? You would think the bouncing air would add heat not take more away? And ultimately, why can't the atoms rebond or reduce vibration without the need to radiate heat? You see planets form from asteroids being drawn together. You would think atoms would also draw together in the same fashion. Why is heat radiated as part of the process of cooling down? In a thermos no external heat is supplied. How does the liquid stay hot? It does cool down eventually but only by radiating the heat over a long time.