In 1960, a young American astronomer named Frank Drake steered a big radio telescope to a nearby star system eager to listen to an alien world. But so far, even after five decades, the answer is an uncanny silence.
Frank Drake's mission to embark upon the alien hunt has since grown to be a large enterprise beginning its operations in 1985, and is known as SETI (Search for Extraterrestrial Intelligence). The core premise of their search is based on the assumption that our cosmos is teeming with life -- not in its primitive form -- but technologically sophisticated ones, similar or possibly better than ours.
The Drake equation estimates the number of detectable civilizations in the observable universe as something around 10,000, with the most neighboring one at least about 1000 light years away. That itself speaks the major difficulty in the alien search -- literally distances of astronomical proportions.
It is assumed that advanced civilizations are capable of using electromagnetic waves to communicate, or even to get our attention. Consequently, the researchers are looking for "narrow band signals," which would serve as the finger print of the extra terrestrial civilizations.
The natural astronomical objects also produce electromagnetic signals, but those are wide spread and could be distinguished from the artificially produced narrow bands. So far, no confirmed, artificially-produced extraterrestrial signal has ever been found. The SETI@home screen saver software asks the general public to contribute their free computing time to analyze the data SETI receives.
Some experts now caution us about the risk of contacting aliens while others advocate a different approach in seeking aliens.
Recently, the renowned British cosmologist, Stephen Hawking warned that "if aliens ever visit us, I think the outcome would be much as when Christopher Columbus first landed in America, which didn't turn out very well for the Native Americans."
As we know, the laws of physics do not allow any travel beyond the speed of light, limiting the possibility of an alien visit. Even if the alien civilizations could accomplish such a high speed travel, that must be at the expense of their enormous resources and time. What on earth would make them to do that? Unless they have mastered laws of physics unknown to us, similar to time travel to breach the space and time, they won't be vacationing on this planet for fun.
In 2008, NASA broadcast the Beatles' song "Across the Universe" aimed at Polaris, the North Star. It would take 431 years for this beam, traveling at the speed of light, to reach the target location. These attempts are more symbolic in nature and reveal the unfathomable nature of space and time that compose our universe.
What if the aliens are so much more advanced than us? Say, their civilization has been around for at least a million years more than ours -- then it's a different game. They might have a completely different mode of communication or transportation. If such aliens want to convey us a message, then broadcasting may not be the best way for them to do that.
They could have genetically engineered us in such a way that we transmit their message in a chemical form called DNA. Our body, which may be nothing more than a carrier of that message, then passes it on to generations that follow. The non-coding DNA, which makes up about 95% of the human genome, is called junk DNA, the functions of which are not completely understood. Some researchers suggest that the evolutionary traits in the junk DNA may help us to identify our alien connection. For now, these suggestions are purely hypothetical in nature. As Carl Sagan noted, "extra ordinary claims require extra ordinary evidences."
Paul Davies, the author of "The Eerie Silence: Renewing Our Search for Alien Intelligence", and director of the Beyond Center for Fundamental Concepts in Science at Arizona State University, has refuted Hawking's arguments in a Wall Street Journal blog. He says that a very advanced civilization may not be aiming for our resources, or even be interested in us, as they might have mastered the know-how of extracting plentiful resources available elsewhere in the universe.
Are we the result of a unique cosmic accident or just one among the many life-infected planets that share a common legacy? There is no guarantee that every intelligent civilization will survive for a long time, as they might destroy themselves or face the inevitable destruction caused by the cataclysmic events that are often unleashed in the cosmos. We don't even know how life began on this planet. How can we be sure that intelligent life exists and flourishes on another planet?
We may never find the alien civilization in our life time, or ever, but I assume we will continue to investigate. There is a fundamental question that arises in the mind of every one of us, "are we alone?" So far, the universe hasn't disclosed all its secrets. As the famous science fiction writer Arthur C. Clarke once said "Either we are alone in the Universe or we are not. Both are equally terrifying."
Our posturings, our imagined self-importance, the delusion that we have some privileged position in the Universe, are challenged by this point of pale light. Our planet is a lonely speck in the great enveloping cosmic dark. In our obscurity, in all this vastness, there is no hint that help will come from elsewhere to save us from ourselves.
The Earth is the only world known so far to harbor life. There is nowhere else, at least in the near future, to which our species could migrate. Visit, yes. Settle, not yet. Like it or not, for the moment the Earth is where we make our stand.
It has been said that astronomy is a humbling and character-building experience. There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly with one another, and to preserve and cherish the pale blue dot, the only home we've ever known.
http://en.wikipedia.org/wiki/Pale_Blue_Dot
From this distant vantage point, the Earth might not seem of particular interest. But for us, it's different. Consider again that dot. That's here, that's home, that's us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every "superstar," every "supreme leader," every saint and sinner in the history of our species lived there – on a mote of dust suspended in a sunbeam.
The Earth is a very small stage in a vast cosmic arena. Think of the rivers of blood spilled by all those generals and emperors so that, in glory and triumph, they could become the momentary masters of a fraction of a dot. Think of the endless cruelties visited by the inhabitants of one corner of this pixel on the scarcely distinguishable inhabitants of some other corner, how frequent their misunderstandings, how eager they are to kill one another, how fervent their hatreds.
It's very likely our definition of intelligence is too basic and hence our assumptions in the "search" inadequate. Although drawing on our own experiences of terrestrial life, Stephen Hawkins parallel to "invasive species" seems reasonable, in an island-hopping scenario, as would be the metaphor of existing deep within enemy territory: You don't send a signal flare high into the sky locating your position to the enemy. Besides would we want our destiny shaped by an outside influence anyway?
And what is that destiny? Perhaps finding outside examples of life (microscopic primitive forms even) would surely aid our understanding of origins of life on this planet and extend our understanding of the properties of life in the solar system/galaxy and universe beyond. Would that data lead us to consider that human civilization could be an inceptive agent towards dispersing future technology and/or life into other areas of the universe? This appears to be what life successfully achieves on this planet for the last 3.5Ga, at least. Life's evolution seems successful (to date) at abstracting away from the universe and it's trend towards entropy and the emergence of intelligence. The pinnacle of that intelligence might be when that intelligence understands itself?
I suspect that we're like people on an island searching for people on other islands by listening for the sound of drums. I also suspect that someone out there knows we're here -- and is watching us but refraining from contact --- for our own good..
Somethings are already understood about some of that DNA. Read up on epigenetics. Non coding sections appear to facilitate the functions and interactions between the coding sections (I think it can form switches that turn other sections on or off for example.)
Why choose to put in some stuff about how are genes are possibly manipulated by space aliens? Do tin foil hats guard against that?
The comments section here is certainly bringing out some -- uh --- unconventional opinions!
Of course, the universe has been around for billions of years, so when I say they don't last long, that may actually be 10,000 years or more. The way we are going, we might not even last that long before we do ourselves in.
Hundreds upon hundreds of thousands of UFO sightings
Thousands of contactees and abductees
Crop circles
Cattle mutilations
Government whisleblowers
Channeled contacts (many of which have predicted very accurate future events)
Very credible evidence supporting the ancient astronaut theory
http://www.amazon.com/dp/0345409469
Probably the only way that we'll find anyone is if they want to be found and are sending out very directed radio signals our way. Humans have done this a small handful of times, including last year when NASA beamed a Beatles song at Polaris. (The signal will get there in 430 years).
Even though I believe that the galaxy abounds with life, we may never find it using SETI, unless we use an active approach and regularly beam radio or light signals at known planets and see if anyone responds. Once Kepler starts finding rocky planets in the habitable zones of their stars, we can make decisions on whether or not to try to get their attention. Of course, as Hawking points out, this could be really dangerous.
The rest of the silence is just distance and the limitations set by the speed of light.