Plat - Some of the answers you have gotten are based on theories not yet proven, as Steve accurately noted. Also, Steve is correct that hydrogen, the fuel for new star formation, will still predominate for trillions, perhaps quadrillions, of years in our universe. <br /><br />Some of this depends on whether dark energy is constant, as in the cosmological constant, or varies over time.<br /><br />In effect, it depends on the springiness of dark energy. <br /><br />Also one must factor in the Pioneer effect, whereby the Pioneer space probes are slowing down for an unknown reason. <br /><br />One theory to account for the latter is that not only mass, but also pressure, exerts gravity - and that negative pressure exerts negative gravity.<br /><br />Locally this would serve to stop any "Big Rip" effect due to positive pressure- if I understand this model correctly.<br /><br />See "Science News," 5/22/04, pp.330-332 for this and other models astronomers are now researching - however, the article does not mention the Pioneer effect - I made that connection on my own.<br /><br />The local portion of universe is not expanding but is more or less gravitationally bound- and this is actually observed. One way is the simple blue shifting of the light spectrum of many local galaxies`<br /><br />Combine this with Steve's accurate noting that hydrogen gas still predominates and you can see why it could be untold vast future time for new star formation in our local portion of universe involving hundreds of millions of light years in diameter.<br /><br />Remember also that astronomers have observed an increase in new star formation during galactic mergers - and that local galaxies will be involved in many future mergers and interactions on the journey towards the Great Attractor and beyond.<br /><br />Finally, you should not ignore the cause of the origin of our universe.<br /><br />Simply stated, Genesis 1:1 states that God created the heavens [perhaps universes in plural] and earth.<br /><br />How