This article discusses whether SETI has ever received a signal from outer space that was artificial in nature thereby signifying that it came from alien life.
Has or will SETI ever detect a signal from an alien species? One thing is for sure with the SETI program and that is it can be compared to looking for a needle in a haystack. There are billions of stars just in our galaxy and then billions of galaxies out there so it could take thousands of years before you actually hit on one with intelligent alien life. Unfortunately many people do not see this and already consider SETI a failure. I hardly see SETI this way for this reason alone. Earth has been around for 4.5 billion years with life probably being about 4 billion years old. Now think about how long we have had radio and TV where our signals are going out to outer space compared to the lifespan of our planet….Get the point? Let’s be conservative and say that we have been transmitting signals into space for about 150 years so if an alien civilization out there was listening to us 160 years ago then they would have heard nothing and therefore concluded that there is no intelligent life near our sun? The key here is going to be able to find an intelligent civilization that is either at our development or further advanced than us. But this might prove that we cannot detect one that is further advanced than us in that who knows if they would even be using radio or television waves and not have developed another means of communication.
Now for the question: Has SETI ever detected anything? The answer would be possibly yes. SETI has been searching for about 50 years now and has had only one signal that could have been artificial. Unfortunately they have not been able to find this signal again despite numerous efforts; even when going back to the exact location it was found. This signal was discovered on August 15, 1977 at the Big Ear Radio Telescope at Ohio State University. It has been nicknamed the “WOW” signal since the researcher, Jerry Ehman, wrote the word wow next to the results on a printout. The signal lasted for approximately 72 signals and had all of the markings of an artificial signal. There have been many speculations about the signals origin but no one really knows. These include an earth-bound signal that got reflected off some space junk, an alien spaceship, or some burst from a star. I would love it to have been from the alien spaceship but this is probably the most unrealistic explanation out there. Besides this signal, SETI has not detected anything that is definitively artificial since but there have been numerous small signals detected that are most likely from pulsars or other space phenomenon.