Draft: Handling particles that leave the atmosphere

The purpose of this MR is to find a way to handle the particles that leave the atmosphere. This bug was noticed using radio when querying the refractive index of a particle. The problem is that when the particle has left the atmosphere, the node becomes a null pointer and when trying to fetch model properties at this point a crash is produced.

There is a preliminary class in this MR that checks if the particle has left the atmosphere and deletes the particle if so, to avoid the crash.

The particles to which that happens are usually very very few, but just one can produce the crash.