This is a cool effect called zooming. While the photo is exposing and the shutter is tripped, you zoom the lens while keeping the camera steady. That way, the middle of the frame is sharp but the edges have cool motion blur. I used it here on some trees in my yard, and at the bottom you can see our clothes line (we avoid the dryer to save energy). It looks like the world is exploding!
Read more about the technique in How to Use Zooming for Explosive Photos.
Since the zoom effect is in-camera, there wasn’t much to edit here. I just added contrast and toned the colors a bit.