I'm pretty sure light is colored and visible outside our atmosphere. Our atmosphere may change the wavelength/color due to interference, but light is due to electrons absorbing energy and jumping to a higher energy level, eventually releasing it, dropping back to their regular level, and producing a ohpyon or 2 of a certain wavelength.
As for what energy is, energy is power. Electrical energy allows us to power up electrical devices. Eating gives us the power (energy) to move and do things. That's the best way I can describe it without using energy in the definiton
