So i was walking to midnight snack the other day, and i happend to look up at a brilliant full moon. I wondered to myself, just how much energy the moon is giving off to illuminate the world around me by exciting the individual atoms within each structure to give off the frequencies of light that i precieve. Then my mind traveled to the amount of energy it even takes to excite an atom enough to give off light and the amount of energy within the light to travel distance.

 

So just how much energy is required for that?

The moon is just reflecting energy, nothing is being excited to give off energy, you are seeing reflected light from the moon and from the objects around you.

The bright side of the moon is the side that is in full daylight. This is why you only get lunar eclipses during a full moon and solar eclipses during a new moon.

Then my mind traveled to the amount of energy it even takes to excite an atom enough to give off light and the amount of energy within the light to travel distance.

 

So just how much energy is required for that?

 

The amount of energy required for an atom to admit light is a function of the ferquency, or wavelength, of the light:

 

[math]E=hv=\frac{hc}{\lambda}[/math]