Hi, I'm a little confused about positronium. Accouring to this article http://www.answers.com/topic/positronium it states on the one hand that it is just an electron and a positron orbiting around their common center, held together by electro-magnetic forces due to their charge. On the other hand it states it behaves very similar to a hydrogen atom just that the proton is replaced by the positron and due to its much lower mass the positron's movement will not be negligible (as it is for the proton). But still the energy of the system seems to be quantized (so the spinning particles are not continuously spiraling into each other until annihilation) and the electron/positron seems to move in orbitals just as electrons in a hydrogen-atom (s-/p-orbitals and so on) which would be somewhat in conflict of stating that the electron is actually orbiting the nucleus/positron because in hydrogen the electron would not orbit the nucleus but instead being "spread out" into an orbital cloud and not being in a single spot at any time. So now what is the valid picture here ? The spread out electron-cloud orbital thing or actually (point) particles orbiting each other ?