My personal opinion is that yes, it is worthwhile to continue the search for extraterrestrial life, but there are many arguments both for and against this search.
Many argue that since the probability of finding evidence of intelligent life is so small, it is a waste of money to continue scanning the sky in search of extraterrestrial intelligence. However, supporters of SETI and other programs note that the amount of taxpayer money that goes into these programs is less than one military helicopter per year.
Several estimates exist as far as just how unlikely it is that we will receive a signal from extraterrestrial life. One of these uses the Drake equation, which estimates the number of technological civilizations in the galaxy. This equation takes into account the number of stars in the galaxy, fraction of those stars having planets, fraction of those planets which are habitable, fraction of those habitable planets on which life originates, fraction of that life which evolves to become intelligent, fraction of those intelligent civilizations which develop technology, and the chance that these technological civilizations are alive at the same time as us. Using generous estimates for the factors in the Drake equation, there are about a million civilizations in the galaxy, which puts the nearest one at about 150 light-years away.
It seems that searching for intelligent life is a discouraging task, due to the huge distances involved and the fact that we may never find anything at all. However, the arguments against continuing SETI and other programs fade in my mind when I think about just how exciting it would be if we could get in touch with another civilization who may be asking themselves the same questions we ask ourselves, or may have some answers. Some people are afraid of what SETI may find, imagining malevolent aliens who may come and eat us all up, and others, like me, are excited by the idea, but I believe it is worth it to keep on looking, if for no other reason than the other discoveries that go along with it. The search for extraterrestrial life is one of the big motivations for further study of the rest of our solar system, especially Mars and the satellites of Jupiter and Saturn. Also, listening to the radio signals that arrive here from the rest of the universe has resulted in several important discoveries that may not have occurred if we were not listening for other life.
This page was last updated June 27, 2015.