1. Begin with a new file, 400x400, with a black bakground, then create a new layer in the layers palette, now take the Polygonal Lasso Tool and make something similar to the shape below.
2. Now right click inside your shape and choose Fill, fill the shape with white, then go to Filter>Distort>Ripple and set the Amount to 999% and the Size to Large. Now should it look something like this.
3. Go to Filter>Blur>Radial Blur and set the Amount to 100, Blur Method Zoom and Quality Good. And that's it you are done!
This is what I came up with.
