The possibility of life on other planets has been one of our oldest doubts.... and oldest hopes. Many believe that we are the only ones here in an infinite and lonely universe, but, as put so eloquently by in the film Contact, based on the novel by Carl Sagan, "If it is just us, it seems like an awful waste of space."
So, could life really exist elsewhere? Why haven't we found other civilizations by now? I hope to be able to provide you with a bit of understanding to the possibility of extraterrestrial life.
The way we can calculate the possibility of life is by the Drake Equation, created by Frank Drake in the early 1960s. It states:
N= [r* x fp x ne x fl x fi x fc] L where:
N = number of possible civilizations to communicate with
R* = is the rate at which stars capable of sustaining like are formed
fp = the fraction of these stars which have planets
ne = the number of planets similar to Earth in the planetary system
fl = the fraction of the Earth-like planets that hold life
fi = the fraction of life that becomes an intelligent civilization
fc = the fraction intelligent civilizations that attempt to communicate
L = the number of years the civilization remains able to communicate.
When these numbers are taken into consideration, we realize that there is a great possibility of life out there. There are about 400 billion stars in our galaxy, so there could be life right next door (relatively speaking, since that may be hundreds of thousands of light years away). Even if there is no life in the Milky Way, there are billions of other galaxies to turn to. We likely will not contact such civilizations in our lifetime, but it gives us a new kind of hope and dream for the future of our planet and the future of mankind.
Stanton Friedman has humorously and quite scientifically shredded the Drake equation. I think his doc doing so is on his website.
http://www.stantonfriedman.com
Hey, I won’t argue the Drake equation...Carl Sagan...don’t get me started on how flawed his work on TTAPS was. I even love sci-fi. I just am not convinced Aliens are visiting us and grabbing people in the middle of the night and/or mutilating cows, or even playing tag with the world’s air forces. Yeah, I am a skeptic..sue me.