What is the likelihood of extraterrestial life existing elsewhere in the universe?

Answer 1

So far, we have no evidence that there is life anywhere else in the universe except here on earth - so the likelihood is 0.

But, knowing that there are billions of stars in thsi galaxy alone, and that there are billions of galaxies, the real likelihood is greater than that.... but it is still small. None of the 200 extra-solar-system planets discovered to date are suitable to sustain life as we understand it... so we need to find a few more candidate-planets, even if they don't have life, before we can begin to say with reasonable certainty that there is a chance of life outside the Earth.

The previous answer is obviously outdated. There are many planets recently found and previously found functional to substain life, if not substaining life already. The moon Titan in our own solar system may even contain life as probes are being sent to evaluate the small ice world around the year 2020. It is claimed to be shooting hot springs once a year on its rotation as the moon actually stretches and ice cracks a bit. This may conclude to water under the surface of the ice, the source of heat is still not of known origin. For more information purchase the box set of the "UNIVERSE" produced by the history channel. If I am exact, the M45 star cluster contains 2 planets that substain an average temperature of 92 degrees and very possibly contain life. It is obsurb to think we are the only planet with intelligent life. While scientists are looking for even molecules and bacteria for evidence, there are greater civilazations to our own with knowledge out of this world, literally. We are predicted ourselves to begin the colonazation of another planet by the year 2100. Parts of our own moon are even being sold off by acres to famous actors and presidents, the Bush family owning land on the moon already, even though they may not live to live on the moon itself their future generations already have a spot. If you don't believe me, Google it. Scientists have discovered a way to make water out of moon dust thus producing the key element to substain life, with a station to produce oxygen and everyday living quarters. The question,"What is the likelyhood of extrterrestial life?" the answer is there is no likely hood. There is extraterrestial life. And we are sure to come into direct contact with many civilizations once we begin our trek into the universe.

Too summarise matts answer is that:

Apparently space (universe) does not end, so people are saying that's it impossible that there is not ONE cell of life in this never ending ness. After all, we are here by chance (big bang) maybe soemone else got lucky....??

I myself do not believe in the Big Bang theory. I understand the universe is expanding but to an extent. I do not believe in the beginning there was space then bang, and everything had spread out. I believe the theory of parallel universes running into each other and mixing. The universe has always been here. There never was a big bang. The stars die and new stars are born. The universe constantly expands to a degree where new matter takes the place of previous matter. There is no one decided point of the center of the universe where matter is expanding from. Thus we have not really but skippied a rock across the lake. The Big Bang is a great theory, because, everything had to come from somewhere, something, so big bang answers those questions to a point. But if that touches the truth of our planets and stars being evolved, where did space come from. The universe or universes is an open ended question. The Big Bang theory does not explain Space, it only explains the evolution of stars and planets. My theory comes from the very little of elements of dust particles and matter that has built up, dissapates and builds up again, it is what Space provides.