Arthur C Clarke once wrote that a trillion years from now an advnaced civilization will look back at us with envy and say "They knew the Universe when it was young."
We may soon discover that intelligent life, indeed, may be in it's "very young" stage in the observable Universe. Its 200 billion galaxies show a clear potential to continue on as we see them today for hundreds of billions of years, if not much longer. Because planets and life are so young in our Universe, says Harvard's Dimitar Sasselov, perhaps "the human species are not late comers to the party. We may be among the early ones."
That may explain why we see no evidence of "them" and may go a long way to explaining the famous Fermi Paradox, which asks if there's advanced intelligent life in the Universe, where are they? Why haven't we discovered any evidence of their existence
The story of the Universe according to Sasselov in is new study, The Life of Super-Earths, looks like this: generations of stars made enough iron and oxygen, silicon and carbon, and all the other elements from the original hydrogen and helium about 13 billion years ago to be able to form the Earth we live on and the planets the Kepler Mission is discovering today.
Stable environments in galaxies that were enriched enough to have planets only became available some nine billion years ago and rocky Earth-like planets and larger super-Earths, only some 7 to 8 billion years ago. And Life had to wait until that time if not later to begin its emergence throughout the Universe. Between 7 and 9 billion years ago, enough heavy elements were available for the complex chemistry needed for life to emerge were in place along with the terrestrial planets with stable environments necessary for chemical concentration.
Enrico Fermi argued that given the old age of the Universe and given the large number of stars and planetary systems and the incredibly short timescale it took humans to develop technology that other origins of life and civilizations in the Milky Way could have had a significant head start and should be significantly more advanced than we are.