Extraterrestrial intelligence refers to intelligent life originating outside of Earth. Of course, as of this point, there is no evidence to support the presence of either intelligent life or just life outside of Earth. We all would like to believe though that there exists life and intelligent life out there somewhere. And it just isn't mere wishing. Scientifically, it remains a possibility too.

It would be highly inconceivable that we humans are the only living inhabitants (or intelligent inhabitants) of this vast universe. The number of planets and galaxies are mind boggling (just so many) and it would be hard for one to be arrogant and think that only Earth has intelligent life in this whole universe.

Dr. Frank Drake in fact came up with an equation that showed that multiple planets potentially exist, that could potentially have civilizations intelligent enough to communicate with Earth. So, there is a scientific basis for the search for extraterrestrial intelligences.

One of those organizations that searches for extraterrestrial intelligence is SETI (Search for Extra-Terrestrial Intelligence). The way that SETI searches for extraterrestrial intelligence is by scanning the skies with radio telescopes to detect radio signals emanating from outer space. The presumption being that if there does exist intelligent life out there - they would (just as we) have developed the ability to communicate using radio waves. However, thus far nothing has been found extraterrestrial in origin; although, there was a lot of excitement over the "wow" signal that was picked up by one of the SETI researchers. However, unfortunately, that signal could never be verified again and hence the origin of that signal remains a mystery.

So, far SETI has not found anything to prove that extraterrestrial intelligences do exist. But, does every extraterrestrial civilization need the same methods of communication as we've developed. I mean we use radio waves to communicate, but do aliens need to use them as well. Could they have not developed some other forms of communication to communicate amongst themselves. It could be a possibility. So, I am not sure that SETI's way should be the only way; although, at this time - I guess that's our best bet to search for extraterrestrial intelligence.

As of now, we know of no other extraterrestrial intelligences. But, how wonderful would it be to find another species like us, residing in another planet far off from Earth. Wonderful - if they are not an aggressive species. Of course, if they are intent on space domination, it would not be too wonderful, would it? But, I do hope to learn in my lifetime that we are not alone. It would be the wildest "breaking news story" of all time.