A thought has cross my mind for some time. What if the universe is expanding, and will start, at a certain point, to collapse (like Fridman's point-of-view). but, if you look at the space-time as finite but limit-less (as Steven Hawking propose), than all of the physics we know today, will be valid throughout the whole process (big bang -> expanding -> colliding). Even the Energy-Conservation principle will be valid. so if I'd say that there was a big bang (with X energy), the energy will be converted to velocity immediately after the big-band(sum of Kinetic energy X of all the particles and the gravity). them, the particles will start to expand (the life we know). they will start losing their Kinetic energy over the potential energy (the gravity). there will be a phase shift to collapse (when the gravity will overcome the kinetic energy). then, all the particles will return to their origin - the big Smash). by that, all the energy will return to the first origin and there will be further more big bangs. this is all true (to my opinion), if there is no other particles at first. also, if there are other phenomenons like other collisions and so, which preserve the general energy/mass and gravity). can anyone help me foundation my opinion or contradict it? pardon my English, i'm Israeli.