When I think of thermal energy I have always imagined that it some "wave" radiating off molecules (like light) but now it seems like heat is not radiating off molecules at all. Heres my understanding:
Molecule have thermal energy if they are vibrating. If a vibrating molecule hits another molecule moving less quickly, it causes it to speed up (I think of it like 2 cars- If one car is speeding towards a parked car then it makes the parked car go flying away). So, thermal energy isn't really a wave like light is-its just when molecules start moving fast.
Is this correct? And if it is then why is heat part of the electromagnetic spectrum? If this spectrum is defined as emitting electromagnetic waves then how is heat within this description?