Circular Area-Light awesome effect

Hi everyone, i've found this amazing video:

and i'm (unsuccesfully) trying to emulate that effect.

There are no lights, so i made a shader for the light ball (just full white color) and a shader for the surface (that use as properties the position and size of the light ball).
Then i tried a diffusion/specular shader effect, but it's nowhere near to this...
if you know, could you explain me how to do it? at least point me in the right direction, i cannot even find on google an article about sphere lights emission, so i'm pretty lost^^
Thanks in advance!

 

http://forum.unity3d.com/threads/single-unreal-engine-spherical-area-light.244415/

 

thanks, it looks quite similiar, i'll give it a shot!