Why is life apparently so scarce in the universe ?
347063
Well extraterrestial planet hunting is only just beginning to be able to discover "smaller" planets. As before only the giant ones indicated their presence, by the effect of their gravity on the parent star.\nRemember even the most powerful telescopes on earth merely see a distant star as a point of light.\nAs for a signal, surveillance equipment is steadily becoming more sophisticated, and discoveries are continously being made to enhance the resolving power of the apparatus. \nMy view is life will not be that common, but a fair few systems will have, or have had life on them at some point. I am sure that in the next twenty years, an umistakeable signal, either intentional or not will be received on earth, and we will know that we are not alone.
1171069
If you consider the size of the known universe and the immense number of stars and planets out there, it is virtually impossible for alien life to not exist.\n\nMost alien life would have evolved naturally like humans.  There is probably also artificial life that was created by those who evolved naturally.\n\nHumans have already created artificial intelligences that are the equals of small insects.  Every year they become more complex.  The only thing that still needs to be done before humans create the first artificial life is that a robot must be designed which is able to reproduce (probably by building copies ... much like the process of budding in primitive organic life).\n\nTo think that life, natural and artificial, does not exist anywhere but Earth is extremely arrogant and naive.
244698
Because it is enormously incredible that in a universe made up of billions of stars, we are the only "intelligent" life that the universe has developed over millions and millions of years. The only thing more exciting than finding fellow intelligent ctreatures in the universe would be for them to find us.\n\nWe know that evolution on this planet was interrupted several times by earth-shattering events. What if those events did not happen on another planet in another galaxy (yes, even one)? How much further evolved and developed would they be? And if that other planet did not have the dead end dinosaurs turned out to be? Millions of years and no sign of intelligence. It took giving a little shrew-like creature a chance to evolve to get to us.\n\nHumans have gotten where we are because of curiosity, a need to find out why things happen and what is happening. Societies that stifle curiosity are the backward ones, destined to be lost in history.
212132
most scientists agree that it is only mere human egocentricism to believe that in the vast expanse of the universe we are the only form of intelligent life, on this microcosm that we like to call Planet Earth.\n\nthe probability of life existing on only one single palnet is unbelievably low..in about 99999999 cases out of 100000000 life evolves in more than one planet, in most case within a few light years of each other on an average.\n\nit is a fair assumption that our universe contains life within a range of a hundred or two hundred light years from here.\n\nas for contacting aliens, it is definitely possible..no civilisation can develop without trampling on common properties of the universe like radio waves,etc. hence we are already concentrating our efforts in this direction since around the '50s , trying to listen for any regularities in the radio wavws that we recieve from the universe..and sending out our own messages in the hope somebody will listen to them \n\nthe difficulty lies in speed..radio waves travel at the speed of light and you can't get faster..but this means that it will take a message sent now from a planet 200 light years away, two more centuries to reach us..but we are still in with a good chance of intercepting such messages..
435187
Of course we're not. How truly arrogant of human race to think we are the only life in the universe. There are billions of star out there with billion of planets. There is no way we are the only ones.
666417
Probably not.  That doesn't mean that we are the only life forms in the universe.  It only means that the probability that these life forms advanced to intelligent life, and have developed the technology to visit us is pretty slim.  Life on earth as we know it could be destroyed by a single meteor.
185479
It would be very arrogant to think that this would be the only planet in the whole universe where any sort of life has developed.  There are so many stars and planets in the universe that even if only a fraction of a percentage were capable of supporting life as we know it, and only a small number of them developed "intelligent" life forms, there would still be billions of alien species.
219187
I do.  There are at least 7*10^22 or 70000000000000000000000 stars out there, so how could anyone really think that only one of those stars have life.  It has been estimated that there are about 1 billion planets with life on them in the entire universe.
612672
well unfortunately, outerspace is a whole lot of nothing, so it doesnt have to take up any space.  granted there are molecules floating around out there, but for the most part there isnt any matter in empty outer space
243321
In space probably not, on another planet almost certain. Look in the sky at night there is something like 100 billion stars that we know of. If each star has say 5-10 planets orbiting it that means there are about 500 billion to 1 trillion planets out there. How can any logical person believe that were are the only 1 that can and does support life?
510802
the universe is too big dude. there has to be other life.
333414
Definitely. What are the odds that, among all the gazillions of planets and stars and galaxies, not ONE other life-form has developed? Hell, I don't even care if we can find sentiency, if there's just LIFE somewhere I'll be happy.
1089748
no, but it would be very stupid to assume that Earth is the only planet that can sustain and contains life.  the universe is gigantic.  i don't think any human can truly grasp how vast the universe is.
940433
Well, if there are billions of stars in an average galaxies, and there are countless galaxies in the universe, even if there is an odd of 1 to trillion, then the probability of having life forms in other galaxy systems appears to be good. \nHowever, life-forms as we know on earth may not be duplicated elsewhere.  Ours is carbon-based.  It is not improbable for other forms of life to exist.  \nBecause of limitations to speed of light, and hence to travelling speed, we, earthlings, may never be able to encounter alien life, as some galaxies are hundreds of millions of lightyears (a lightyear is the distance travel by light in 1 year) away, that is it takes light hundreds of millions years to reach us from that distant galaxy.\nSo even if the intelligent life-form on the outskirts of our known universe were to evolved a million years before us, and if such intelligent life-forms were to be able to travel at the speed of light, they cannot reach us in another hundreds of million years.\nBy then, our enlarged sun would have scorched our earth into an uninhabitable region, meaning all lives on earth would be wiped out.
494685
You must not be a native English speaker. I think what you are asking is:\n\n1. Is outer space empty besides planets and stars...?\n2. How and when did the universe come into existence?\n\nNo; space is not empty it is filled with gas and dust(known as the "interstellar medium"). The density of the ISM varies widely between a few to hundreds of molecules per cubic meter. Even intergalactic space is not empty. It also contains traces of gas and dust. Latest estimates are 15 billion years for the age of the universe
705988
My gut agrees with you, but I wouldn't jump to any conclusions. A sobering (and excellent) read is Rare Earth by Ward and Brownlee. One is an astronomer, the other a geologist. They make a convincing case that sentient life elsewhere in the universe is probably quite rare. At a minimum, they make minced meat out of the Drake Equation. Still, with so many possibilities ...\n\nThe other thing to remember is that first and possibly second generation of post-Big Bang stars could never have supported planets with life of any kind. It took billions of years before stars produced sufficient quantities of heavy elements that are essential for life.\n\nand, all those stars and all those galaxies don't exist simultaneously. As we look farther out into space, we are more and more likely looking at objects that no longer exist.\n\nso, having said all that, we must consider this. a) sentient beings are probably quite rare - whether you accept Ward and Brownlee's extreme argument or not. b) that life could only have existed for, say, the last 8 or 9 billion years of the universe's existence. c) the distances to other stars in our galaxy are vast, but the distances *between* the galaxies are mind boggling vast (there's a reason that even in Star Trek, with it's fantasy warp drive, the story lines are all confined to our own galaxy).\n\nJust food for thought.
762604
Because living forever would get boring! And there would be too many people on earth! Not enough space!