For centuries, humanity has been captivated by the idea of finding intelligent life beyond our planet.
In many ways, this is a consequence of astronomers discovering that the planets of our Solar System were not that different from Earth, as well as the fact that our Sun is one of the billions within our galaxy (and our galaxy one of trillion within the cosmos).
However, it has only been within the past century that any efforts to find life beyond Earth have been mounted. These efforts are largely the result of the development of radio astronomy, where radio antennas are used to detect radio waves from cosmic sources.
In the past few decades, our methods have grown and matured, to the point where we are able to search far and wide for signs of life.
But as Enrico Fermi famously said, “where is everybody?” In other words, if the possibility of intelligent life is even remotely possible, why has humanity not found any evidence of life out there?
This question is not only the basis of the famous Fermi Paradox, but it also lies at the heart of humanity’s ongoing Search for Extra-Terrestrial Intelligence (SETI).
So how are we going about this task? What are our methods and what kinds of limitations we are working with? And while we’re at it, just how likely are we to find evidence of extra-terrestrialintelligences (ETIs) in our galaxy or the Universe at large?