Until now, scientists have been so focused on unlocking the secrets of the universe's past that few have bothered to think much about what will happen in the future. It is equally true that our current cosmological epoch has no central place in time. We live in an important time in the universe's development, but interesting events will continue to occur as long as the universe exists. Each cosmological decade represents a tenfold increase in the number of years which have elapsed since the beginning of time. We live at the mid-point of the Stelliferous Era, a time in the history of the universe when energy is generated by the birth, life and death of stars.
Red dwarfs are real misers at burning hydrogen.
They hoard their energy and some will still be around 10 trillion years from now when the last sun- like star has long since exhausted its fuel supply and collapsed into a white dwarf. When star formation and stellar evolution cease, the universe will move into the Degenerate Era. During this era, galaxies will begin to relax dynamically with some stellar remnants moving out to the edge of the galaxy and others falling to the center. But on average this will happen only once every quadrillion years in a galaxy the size of the Milky Way. As they are depleted from the galactic halo, however, the energy level in the universe will continue to decline.