Yes, There Have Been Aliens

[link to online.liebertpub.com]

conclusion of the paper:
"In conclusion, we have shown that recent advances in
astrobiology and exoplanet studies mean that an empirically
derived lower limit can now be placed on the probabilities
that even one other technological species has ever evolved
in the Universe or in our galaxy. This limit provides a
framework for discussions of both life in its cosmic context and questions about trajectories of technological species relevant to our own issues of global sustainability."

in other words if u cross the line maybe u can meet a ET

Aye!