Extraterrestrial life is life that does not originate from Earth. It is also called alien life, or, if it is a sentient and/or relatively complex individual, an "extraterrestrial" or "alien" (or, to avoid confusion with the legal sense of "alien", a "space alien"). These as-yet-hypothetical life forms range from simple bacteria-like organisms to beings with civilizations far more advanced than humanity. Although many scientists expect extraterrestrial life to exist, there is no unambiguous evidence for its existence so far.
- People have been willing to accept that the government is lying to us, but [are now also] more willing to accept the concept of aliens and other life forms. There's just a slew of stuff out there right now. It's been people's closet belief system, and now it's coming out of the closet.
- Our sun is one of 100 billion stars in our galaxy. Our galaxy is one of billions of galaxies populating the universe. It would be the height of presumption to think that we are the only living things in that enormous immensity.
- Wernher von Braun, Text of the Address by von Braun Before the Publishers' Group Meeting, The New York Times Text of the Address by von Braun Before the Publishers' Group Meeting Here 29 April 1960 L. 20, column 2 Wells (April 29, 1960), l. 20, column 2.
- Two possibilities exist: Either we are alone in the Universe or we are not. Both are equally terrifying.
- The only thing that scares me more than space aliens is the idea that there aren't any space aliens. We can't be the best that creation has to offer. I pray we're not all there is. If so, we're in big trouble.
- Ellen DeGeneres, Seriously... I'm Kidding, (2011)
- Any entity – no matter how many tentacles it has – has a soul.
- Guy Consolmagno Vatican Astronomer Pope Francis says he would baptize aliens
- If, for example, tomorrow an expedition of Martians came to us here and one said ‘I want to be baptised!’, what would happen? Martians, right? Green, with long noses and big ears, like in children’s drawings? When the Lord shows us the way, who are we to say, ‘No, Lord, it is not prudent! No, let's do it this way’. Who are we to close doors?
- It [the beauty of physics] has nothing to do with human beings. Somewhere, in some other planet orbiting some very distant star, maybe another galaxy, there could well be entities that are at least as intelligent as we are, and are interested in science. It is not impossible. I think there probably are lots. Very likely none is close enough to interact with us, but they could be out there very easily. And suppose they have [...] very different sensory apparatus and so on, they have seven tentacles, and they have fourteen little funny-looking compound eyes, and a brain shaped like a pretzel, would they really have different laws? Lots of people would believe that, and I think it is utter balony. ... They [the three principles in nature] are emergent properties. ... Life can emerge from physics and chemistry plus a lot of accidents. The human mind can arise from neurobiology and a lot of accidents.
- They stared at each other, man and alien, or more correctly alien and alien—for this is what they were to each other. Alien meaning different, alien meaning unknown.
- Harry Harrison, Plague from Space (1965), Chapter 13.
- Mark well each little Star, whose rays
In distant splendor meet thy gaze;
Each is a world by Him sustained,
Who from eternity hath reigned.
Each, kindled not for earth alone,
Hath circling planets of its own,
And beings, whose existence springs
From Him, th' all-powerful King of kings.
- Felicia Hemans, The Stars, from Hymns for Childhood, first published 1824.
- A Man that is of Copernicus’s Opinion, that this Earth of ours is a Planet, carry’d round and enlighten’d by the Sun, like the rest of the Planets, cannot but sometimes think that it’s not improbable that the rest of the Planets have their Dress and Furniture, and perhaps their Inhabitants too as well as this Earth of ours.
- And pray that there's intelligent life somewhere up in space...
...'cos there's bugger-all down here on Earth
- But who shall dwell in these worlds if they be inhabited? … Are we or they Lords of the World? … And how are all things made for man?
- Johannes Kepler, quoted in "The Anatomy of Melancholy".
- Recently, the press has been filled with reports of sightings of flying saucers. While we need not give credence to these stories, they allow our imagination to speculate on how visitors from outer space would judge us. I am afraid they would be stupefied at our conduct. They would observe that for death planning we spend billions to create engines and strategies for war. They would also observe that we spend millions to prevent death by disease and other causes. Finally they would observe that we spend paltry sums for population planning, even though its spontaneous growth is an urgent threat to life on our planet. Our visitors from outer space could be forgiven if they reported home that our planet is inhabited by a race of insane men whose future is bleak and uncertain.
- I don’t believe in any of Earth’s monotheistic religions, but I do believe that one can construct an intriguing scientific definition of God, once you accept the fact that there are approximately 100 billion stars in our galaxy alone, that each star is a life-giving sun and that there are approximately 100 billion galaxies in just the visible universe. Given a planet in a stable orbit, not too hot and not too cold, and given a few billion years of chance chemical reactions created by the interaction of a sun’s energy on the planet’s chemicals, it’s fairly certain that life in one form or another will eventually emerge. It’s reasonable to assume that there must be, in fact, countless billions of such planets where biological life has arisen, and the odds of some proportion of such life developing intelligence are high.
- Now, the sun is by no means an old star, and its planets are mere children in cosmic age, so it seems likely that there are billions of planets in the universe not only where intelligent life is on a lower scale than man but other billions where it is approximately equal and others still where it is hundreds of thousands of millions of years in advance of us. When you think of the giant technological strides that man has made in a few millennia - less than a microsecond in the chronology of the universe - can you imagine the evolutionary development that much older life forms have taken? They may have progressed from biological species, which are fragile shells for the mind at best, into immortal machine entities - and then, over innumerable eons, they could emerge from the chrysalis of matter transformed into beings of pure energy and spirit. Their potentialities would be limitless and their intelligence ungraspable by humans.
- Some contend that encountering a highly advanced civilization - even one whose technology is essentially comprehensible to us - would produce a traumatic cultural shock effect on man by divesting him of his smug ethnocentrism and shattering the delusion that he is the center of the universe. Carl Jung summed up this position when he wrote of contact with advanced extra terrestrial life that the "reins would be torn from our hands and we would, as a tearful old medicine man once said to me, find ourselves 'without dreams'...we would find out intellectual and spiritual aspirations so outmoded as to leave us completely paralyzed. I personally don't accept this position, but it's one that's widely held and can't be summarily dismissed.
- Why would a vastly superior race bother to harm or destroy us? If an intelligent ant suddenly traced a message in the sand at my feet reading, "I am sentient,; let's talk things over," I doubt very much that I would rush to grind him under my heel. Even if they weren't super intelligent, though, but merely more advanced than mankind, I would tend to lean more toward benevolence, or at least indifference, theory. Since it's most unlikely that we would be visited from within our own solar system, any society capable of transversing light-years of space would have to have an extremely high degree of control over matter and energy. Therefore, what possible motivation for hostility would they have? To steal our gold or oil or coal? It's hard to think of any nasty intention that would justify the long and arduous journey from another star.
- Anything we can imagine about such other life forms is possible, or course. You could have psychotic civilizations, or decadent civilizations that have elevated pain to an aesthetic and might covet humans as gladiators or torture objects, or civilizations that might want us for zoos or scientific experimentation, or slaves or even food. While I am appreciably more optimistic, we just can't be sure what their motivations will be.
- As all regions below are replenished with living creatures... so may the heavens above be replenished with beings whose nature we do not understand. He that shall well consider the strange and wonderful nature of life and the frame of the Animals, will think nothing beyond the possibility of nature, nothing too hard for the omnipotent power of God. And as the Planets remain in their orbs, so may any other bodies subsist at any distance from the earth, and much more may beings, who have sufficient power of self motion, move whether they will, and continue in any regions of the heavens whatever, there to enjoy the society of one another, and by their messengers or Angels to rule the earth and convers with the remotest regions. Thus may the whole heavens or any part thereof whatever be the habitation of the Blessed, and at the same time the earth be subject to their dominion. And to have thus the liberty and dominion of the whole heavens and the choice of the happiest places for abode seems a greater happiness than to be confined to any one place whatever.
- Can we and all nations not live in peace? In our obsession with antagonisms of the moment, we often forget how much unites all the members of humanity. Perhaps we need some outside, universal threat to make us recognize this common bond. I occasionally think how quickly our differences worldwide would vanish if we were facing an alien threat from outside this world. And yet, I ask you, is not an alien force already among us? What could be more alien to the universal aspirations of our peoples than war and the threat of war?
- President Ronald Reagan, United Nations General Assembly, 21 September 1987.
- Star Trek offers an almost infinite number of exciting Science Fiction stories, thoroughly practical for television? How? Astronomers put it this way:
- Ff^2 (MgE) - C^1R1^1 x M = L/So
- Or to put it in simpler terms, by multiplying the 400,000,000,000 galaxies (star clusters) in the heavens by an estimation of average stars per galaxy (7,700,000,000,000,000,000,000,000,000,000,000), we have the approximate number of stars in the universe, as we understand it now. And so…
- …if only one in a billion of these stars isa “sun” with a planet…
- …and only one in a billion of these is of earth size and composition…
- …there would still be something near 2,800,000,000,000,000,000,000,000,000 worlds with a potential of oxygen-carbon life…
- or… (by the most conservative estimates of chemical and organic probability), something like three million worlds with a chance of intelligent life and social evolution similar to our own.
- Vina: They found me in the wreckage, dying. A lump of flesh. They rebuilt me. Everything works. But they had never seen a human. They had no guide for putting me back together.
- Since, in the long run, every planetary society will be endangered by impacts from space, every surviving civilization is obliged to become spacefaring — not because of exploratory or romantic zeal, but for the most practical reason imaginable: staying alive.
- Carl Sagan, Pale Blue Dot.
- I believe much of it. Some of it I will take in a neutral fashion. I’ll say, “I’m not sure you’re right. But somebody else give me something else by way of a projection.” I feel much of what he said can be put to scientific test and found pretty valid. The most negative reaction has come from theologians. They hate it. Because obviously everything Von Daniken suggests by way of theory – evolutionary and otherwise goes very much against the New Testament. So when you read read a book like Crash Go the Chariots, which was supposed to be the definitive knockdown of the Von Daniken book, you look at the critic’s credits. He’s written nothing but theological books. What he’s defending is the Mother Church. So his rebuttal to Von Daniken is subject to considerable thought and second guessing.
- I would vote for Bach, all of Bach, streamed out into space, over and over again. We would be bragging of course.
- Lewis Thomas in The Lives of a Cell: Notes of a Biology Watcher, on what message to send to an extraterrestrial civilization.
- I think the surest sign that there is intelligent life out there in the universe is that none of it has tried to contact us.
- No one would have believed in the last years of the nineteenth century that this world was being watched keenly and closely by intelligences greater than man's and yet as mortal as his own; that as men busied themselves about their various concerns they were scrutinised and studied, perhaps almost as narrowly as a man with a microscope might scrutinise the transient creatures that swarm and multiply in a drop of water. With infinite complacency men went to and fro over this globe about their little affairs, serene in their assurance of their empire over matter. It is possible that the infusoria under the microscope do the same. No one gave a thought to the older worlds of space as sources of human danger, or thought of them only to dismiss the idea of life upon them as impossible or improbable. It is curious to recall some of the mental habits of those departed days. At most terrestrial men fancied there might be other men upon Mars, perhaps inferior to themselves and ready to welcome a missionary enterprise. Yet across the gulf of space, minds that are to our minds as ours are to those of the beasts that perish, intellects vast and cool and unsympathetic, regarded this earth with envious eyes, and slowly and surely drew their plans against us. And early in the twentieth century came the great disillusionment.
- H.G. Wells, "The War of the Worlds".
- Across an immense ethereal gulf, minds that are to our minds as ours are to the beasts of the jungle - intellects vast, cool and unsympathetic - regard this Earth with envious eyes and slowly and surely drawtheir plans against us...
- I believe we are the only sentient beings in the universe, and I believe that 500 years from now, we will still be the only sentient beings around.