Mads writing for hagbarth.net:

Nuke 8 secretly introduced a undocumented node called ParticleToImage. This node can be used to turn a particle system into raw image data, containing XYZ positions, Scale, and Color data.

I assume the node was introduced to bridge the gab between 3D scenes and the new BlinkScript node.

The Blinkscript Node is going to be huge. The ParticleLights Gizmo isn't bad either. Have a look.