  The Cauchy problem is revisited for the so-called relativistic Vlasov-Poisson
system in the attractive case. Global existence and uniqueness of spherical
classical solutions is proved under weaker assumptions than previously used. A
new class of blowing up solutions is found when these conditions are violated.
A new, non-gravitational physical vindication of the model which (unlike the
gravitational one) is not restricted to weak fields, is also given.
