In past eons, new stars have replaced the dying stars by the action of gravity pulling together cosmic clouds of gas. But the universe has been expanding and thinning out since its Big Bang beginning, large concentrations of gas are gradually being disrupted, and in the future the density of gas will not be sufficient for new star formation. In addition, the lighter chemical elements that fuel most stars, such as hydrogen and helium, will have been used up in previous generations of stars. At some point in the future, new stars will cease being born. Slowly but surely, the stars of our
...more
