Does Intelligent Life Exists in the Cosmos?
The question is most likely wrong. It is not: “Does intelligent life exist on other worlds” but “How could intelligent life not exist on other worlds.
The study of the Universe is designed to answers three fundamental questions; 1) why are we here? 2) where did we come from? and 3) where are we going. To this end the opening lines of the original Star Trek TV series defined the whys and hows: “to explore strange new worlds, to seek out new life and new civilizations, to boldly go where no man has gone before.” Humankind’s quest to answer these questions led to the creation of a belief structure called religion and a knowledge based system enveloped in science.
Prior to jettisoning people way beyond Earth’s surface, mankind peered into the sky to unravel the universe. With super-sophistication, our eyes in the sky now identify exoplanets almost on a daily basis. The Hubble Ultra Deep Field Image shows the universe as it was a mere 400 million years from its birth, that is 13.3 billion years ago. The image allowed scientists to determine that the Universe contains at least 100 billion galaxies. New estimates of the number of stars in the universe is about 300 sextillion, that is 300 x 10(exp21).
Topical results from NASA’s Kepler Space Telescope estimates “Our Milky Way galaxy, with at least 100 billion stars, is home to at least 100 billion alien planets,” that is one planet for every star.  Its then reasonable to project about 300 sextillion exoplanets in the cosmos or 300 x10(exp21), that is 300,000 trillion.
Other than a direct comparison to the size of the US debt, in order to comprehend this number, a group of scientists at the University of Hawaii recently estimated there are 7.5 x 10(exp18) grains of sand on Earth, that is 7.5 trillion grains. In other words, there are 300,000 / 7.5 or 40,000 times more exoplanets in the Universe than grains of sand on Earth.
The major obstacle in our quest to contact other life forms is distance. The closest star, Proxima Centauri, is 4.243 light years from earth. For example, “the Voyager 1 spacecraft is on an interstellar mission. It is traveling away from the Sun at a rate of 17.3 km/s. If Voyager were to travel to Proxima Centauri, at this rate, it would take over 73,000 years to arrive. If we could travel at the speed of light, an impossibility due to Special Relativity, it would still take 4.22 years to arrive!” So meeting alien life is out of the question for the foreseeable future.
This leaves radio waves, which move at the speed of light. Bilateral communication by electromagnetic radiation with advanced life forms from Proxima Centauri would take about 8.5 years. Possible if the life form is sufficiently advanced and enjoys public broadcasting. Hopefully, they have an ear for Opera, first broadcasted ‘in 1910 from the stage of the New York City Metropolitan Opera Company when Enrico Caruso and Emmy Destinn sang arias from Cavalleria Rusticana and I Pagliacci.” We leave it up to SETI, which has been in existence since 1984, to make that determination.
EMR communication precludes the existence of primitive life forms. Using earth as a model, only 100 years of Earth’s 4.5 billion years existence was inhabited with life forms sophisticated enough to communicate electronically. Observatories today are as much, if not more, electronics and computers as optics. All three of which run by a set of mathematical and physical rules. The point is, as long as the mathematics is correct, it is possible to predict the outcome with a high degree of certainty.
So what are the rules governing intelligent life? First and foremost, the Earth has some “intelligent” life. The Earth is one of eight planets. That is, given some 4.5 billion years there is a 100% probability that a planet in a habitable zone will eventually generate intelligent life and a 12.5% probability of a planet in a solar system will be in a habitable zone. Working quite conservatively, if only one in a million solar systems have a mature planet in the habitable zone with the right chemistry to spawn life, then there is a 0.0001% [(1.0 x 10(exp-6)) x (1 x(10(exp2))] probability life will form. Discounting this by another million that life on the exoplanet will evolve into intelligent life, then only one in a trillion exoplanets [1.0 x 10(exp-12)] planets will have intelligent life.
Therefore, 300 billion exoplanets in the universe have intelligent life; [(300 x10(exp21)) x [(1.0 x 10(exp-12))]. The question then becomes “where are they,” not “are there any.” With the incompressible numbers representing the cosmos, betting on the probably that at least one other planet in the universe harbors advanced life forms, is a sure bet. It’s no different than playing a slot machine with all 300 billion slots painted red. Only a fool would play black.
Sooner or later, space exploration of our solar system may identify the foot print of primitive life forms. The likelihood of finding little green men and women from our solar systems is close to absolute zero. The likelihood of finding aliens from another solar system roaming our sky or soil is dubious at best. Though, findings like the Antikythera Mechanism dating from around 65 B.C. are somewhat perplexing. Possibly we just don’t give our ancestors nearly the credit they deserve.
In closing, like sand throughout Earth, so is intelligent life beyond our sky.
 Hubble Digs Deeply, Toward Big Bang, NASA; http://www.nasa.gov/vision/universe/starsgalaxies/hubble_UDF.html
 Scientists Find 200 Sextillion More Stars in the Sky, Associated Press, December 1, 2010; http://www.foxnews.com/scitech/2010/12/01/scientists-sextillion-stars
 Milky Way’s Alien Planets May Number 100 Billion Or More, Surprising New Study Suggests, Huffington Post, January 3, 2013; http://www.huffingtonpost.com/2013/01/02/milky-way-alien-planets-100-billion_n_2399178.html
 Are there more grains of sand on Earth or stars in the sky? Scientists finally have an answer, Mother Nature Network, Bryan Nelson, September 25 2012; http://www.mnn.com/earth-matters/wilderness-resources/stories/are-there-more-grains-of-sand-on-earth-or-stars-in-the-sk
 The Nearest Star, NASA; http://heasarc.nasa.gov/docs/cosmic/nearest_star_info.html
 Birth of public radio broadcasting, Wikipedia; http://en.wikipedia.org/wiki/Birth_of_public_radio_broadcasting
 High tech helps solve mystery of ancient calculator, Network World, John Cox, November 22, 2006; http://www.networkworld.com/news/2006/112706widernet.html?page=2