8. The fate of galaxies

‘The fate of galaxies’ speculates on the ultimate fate of the Universe. There are three possible scenarios for the end of the Universe: steady acceleration, increased acceleration, or deceleration. If expansion continues at a steady rate, eventually all baryonic matter will be used up. Galaxies will be swallowed by black holes, which will eventually consume themselves. If the expansion of the universe speeds up, eventually the universe will break apart in a ‘Big Rip’. If the Universe begins to contract then the ‘Big Crunch’ will occur, essentially the Big Bang in reverse. However, these theories are all mere speculation, and nobody alive today will ever know for sure.