The file is a Maya 8.5 Unl. file.

It will not open with Maya 8 or earlier, sorry

I explained exactly what I did to make the file, so for you to create it yourself, it should only take you about 15-20 minutes

1. Select your outer, rotating, smaller sphere.
2. Goto Particles > Emit From Object.
3. Adjust the particle emitter's rate and speed to taste.
4. Adjust the ParticleShape lifespan to die quickly by setting it to a low value.

Thats pretty much it.

For more details on working with particles and emitters, please check the help under Particles and Dynamics

Good luck!