 The intricate structure of this stellar debris forms a dramatic Reverse S shape. Looking at the detail, the nebula shows a series of dense knots in the clouds of gas. Now what's going on here is that the radiation from the dying star is carving the knots into shape, much like water flowing around a rock in a stream. And these are all pointing towards the center of the nebula. The knots are a reminder of just how vast the planetary nebula is. Just like in the helix nebula, each and every one is the size of our entire solar system.