Spore is releasing one of their prototypes they’ve used to check out different aspect of the game. In this, called the Particleman, we can see how the gravity, star formations and other things work.
ParticleMan has the following elements:
Particles — point masses which interact with each other
Gravity Wells — fixed point masses which attract or repel particles(depending on magnitude, which can be negative), but do not move or change mass without user input
Particle Guns — sources that spit particles out at a given angle and velocity
Gravity Wells and Particle Guns may only be placed on the green grid in the z=0 plane.
The Iso Surface — an isosurface geometry object derived from the positions and masses (which act as field strengths) of the particles.
Check out Spore.com for more info and download.