
A recent work looked at the past, and set a lower bound on the probability that one or more technological species have evolved anywhere and at any time in the history of the observable Universe \cite{Frank_2016}.
The authors conclude that is very likely that humanity is not the first technological intelligence that has evolved, so far, in the Universe. ``\href{http://www.nytimes.com/2016/06/12/opinion/sunday/yes-there-have-been-aliens.html}{Yes, There have been aliens}'' seems to be the conclusion of this work, although the \href{https://www.authorea.com/25815}{Fermi paradox} seems to point out that either intelligence is a very rare avenue of life and/or alien civilizations do not last very long, or that aliens like to play hide-and-seek with us.
