How can I create a material that looks like this?
Thanks!
3 Concentric Spheres with Emission Particles
Blur in Compositor
Render result and 3 Concentric Spheres each with a particle system. Image above.
Click on images to see larger view.
Compositor with Blur and Alpha Over Nodes. Image Above.
Particle Settings. 3 Panel of which 2 are pinned. Unpinned is the largest sphere particle system. Image above.
The 3 Object particles and the material settings. 2 are pinned.
Please experiment to your taste and improve. Consider using a more irregular sphere in the center. You may look at the movement of particle system on many frames and choose some particular frame.
Sloppy Imitation which may serve as a starting point. Of course there are alternative and more CPU intensive ways to do this.