Nine comps of animated northern lights using AE's built-in Fractal Noise and Trapcode Shine. Trapcode Particular used for the stars. Resurrected from trapcode-people.
Download AE 6.0 AEP
Description: Fractal Noise is used on the bottom layer to create the base for the effect. It has keyframes on "Evolution" which means it will change shape over time. Switch off all layers above it to see how it looks. Above that is a colorization layer that uses Colorama (built-in AE effect) to generate the color gradient. Then a mask is applied. Trapcode Shine is used in an adjustment layer above to create the look of light rays / northern lights. For finish, a starfield is added on top and then the layer with trees.