How can something give out light?

Question: How can something give out light?
- Keywords:
  light,
  object,
  wave
Asked by Zealousy to Rob on 19 Jun 2015.
- Rob Temperton answered on 19 Jun 2015:
  
  It depends on what that something is. There are a bunch of different process that are all slightly different. However, the general explaination is that light is emitted when electrons loose energy – ie they transition from a high energy state to a low energy state and emmit a photon in the process. The wavelength of the light is determined by how big the energy jump is.
  
  Rob

Question: How can something give out light?