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Eyes Turned Skyward
A star gazing, rocket riding, moon walking quote collection

Search for Extra-Terrestrial Intelligence



Even if we never reach the stars by our own efforts, in the millions of years that lie ahead it is almost certain that the stars will come to us. Isolationism is neither a practical policy on the national or cosmic scale. And when the first contact with the outer universe is made, one would like to think that Mankind played an active and not merely a passive role — that we were the discoverers, not the discovered.

— Arthur C. Clarke, The Exploration of Space, 1951.

To consider the Earth as the only populated world in infinite space is as absurd as to assert that in an entire field sown with millet, only one grain will grow.

— Metrodorus of Chios, 4th century BCE.

There are innumerable worlds of different sizes. In some there is neither sun not moon, in others they are larger than in ours and others have more than one. These worlds are at irregular distances, more in one direction and less in another, and some are flourishing, others declining. Here they come into being, there they die, and they are distroyed by collision with one another. Some of the worlds have no animal or vegetable life nor any water.

— Democritus, according to Hippolytus, Refutation of the Heresies (trans. W. K. C. Guthrie) 4th centruy BC.

If atom stocks are inexhaustible,
Greater than power of living things to count,
If Nature's same creative power were present too
To throw the atoms into unions &mdashexactly as united now,
Why then confess you must
That other worlds exist in other regions of the sky,
And different tribes of men, kinds of wild beasts.

— Titus Lucretius Carus, De Rerum Natura (trans. Alban Dewes Winspear, 1955), 1st Century BCE.

Since stars appear to be suns, and suns, according to the common opinion, are bodies that serve to enlighten, warm, and sustain a system of planets, we may have an idea of the numberless globes that serve for the habitaton of living creatures.

— William Herschel, 1795.

We all confidently believe that there are at present, and have been from time immemorial, many worlds of life besides our own… . [This] may seem wild, and visionary; all I maintain is that it is not unscientific.

— Sir William Thomson (later Lord Kelvin), presidential address to the British Association for the Advancement of Science, August 1871.

The idea that in other worlds life may exist in conditions widely different from those prevailing on this world in which we live, however plausible at first, becomes highly improbable when tested by the light shed on this subject by the accumulated knowledge of modern research in the fields of astronomy, geology, spectroscopy, and chemistry, especially that branch of the latter science pertaining to organic compounds… .
We conclude, then, that our earth is a highly distinguished planet, at present favored above hundreds and perhaps above thousands with conditions which have not alone rendered the existence of vegetable and animal life possible, but developed it to the highest stage of organic existence: namely, civilized and enlightened human races, able to investigate and discuses the highest problems in the universe, which are the laws of its creation, progress and ultimate purposes.

— 'Is Earth The Only Inhabited World?', Scientific American, 17 May 1873.

If they be inhabited, what a scope for misery and folly; if they be na inhabited, what a waste of space.

— Attributed to Thomas Carlyle (1795-1881) on the first page of John Burroughs' 1920 book Accepting the Universe. It may have been the inspiration for a more optimistic line in the 1997 movie Contact, where in the first scene Ellie's dad (played by David Morse) says:

The Universe is a pretty big place… And the one thing I know about nature is it hates to waste anything. So I guess I'd say if it is just us, an awful lot of space is going to waste.

The earth is not alone, it is not like a single apple on a tree; there are many apples on the tree, and there are many trees in the orchard.

— John Burroughs, The Breadth of Life, 1915.

The reader may seek to consign these speculations wholly to the domain of science-fiction. We submit rather, that the foregoing line of argument demonstrates that the presence of interstellar signals are entirely consistent with all we now know… . We therefore feel that a discriminating search for signals deserves a considerable effort. The probability of success is difficult to estimate; but if we never search the chance of success is zero.

— Giuseppe Cocconi & Philip Morrison, 'Searching for Interstellar Communications,' the first formally argued rationale for SETI published in a scientific journal, Nature, vol. 184, no. 4690, pages 844-846, 19 September 1959.

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 we are the only living things in this enormous immensity.

— Wernher von Braun, quoted in the New York Times, 29 April 1960.

Drake Equation

Where N = the number of civilizations in our galaxy with which communication might be possible.
R* = the average rate of star formation per year in our galaxy.
fp = the fraction of those stars that have planets.
ne = the average number of planets that can potentially support life per star that has planets.
fℓ = the fraction of the above that actually go on to develop life at some point.
fi = the fraction of the above that actually go on to develop intelligent life.
fc = the fraction of civilizations that develop a technology that releases detectable signs of their existence into space.
L = the length of time such civilizations release detectable signals into space.

— Frank Drake. This is now known as the Drake Equation, first presented at a conference in Green Bank, West Virginia, it helped establish SETI as a scientific discipline. 1961.

Forty years as an astronomer have not quelled my enthusiasm for lying outside after dark, staring up at the stars. It isn't only the beauty of the night sky that thrills me. It's the sense I have that some of those points of light are the home stars of beings not so different from us, daily cares and all. who look across space with wonder, just as we do.

— Frank Drake, originator of the Drake equation, Is Anyone Out There?, 1992

The estimated equilibrium temperature of GJ 581g is 228 K, placing it squarely in the middle of the habitable zone of the star and offering a very compelling case for a potentially habitable planet around a very nearby star… . If the local stellar neighborhood is a representative sample of the galaxy as a whole, our Milky Way could be teeming with potentially habitable planets.

— Steven S. Vogt, R. Paul Butler, Eugenio J. Rivera, Nader Haghighipour, Gregory W. Henry and Michael H. Williamson, 'The Lick-Carnegie Exoplanet Survey: A 3.1 M⊕ Earth Planet in the Habitable Zone of the Nearby M3V Star Gliese 581.' The planet is the most earthlike planet yet discovered, at a press conference the same day Steven Vogt said, "the chances of life on this planet are almost 100%." Submitted for publication in The Astrophysical Journal on 29 September 2010

Our passionate preoccupation with the sky, the stars, and a God somewhere in outer space is a homing impulse. We are drawn back to where we came from.

— Eric Hoffer, the New York Times, 21 July 1969.

A single message from space will show that it is possible to live through technological adolescence… . It is possible that the future of human civilization depends on the receipt of interstellar messages.

— Carl Sagan, 'The Quest for Extraterrestrial Intelligence.' Smithsonian magazine, May 1978.

Arecibo Message

— Arecibo message. First intentional outbound extraterrestrial communication. This single message was broadcast from Earth in the direction of the globular star cluster M13 during the dedication of the Arecibo Observatory. It includes (from the left) the numbers one through 10, atomic numbers of hydrogen, carbon and other atoms in DNA, more DNA facts, a human figure graphic and scale, our Solar System and data on the telescope that transmitted the message (color added for human reading clarity, the original message carried no color coding in its 1679 pixels). Frank Drake et al., 16 November 1974.

Cosmic Call

— First page of the Cosmic Call or Dutil-Dumas Lincos message sent by the (now defunct) Team Encounter. First sent towards Cygnus from the Evpatoria RT-70 radio telescope in the Ukraine, 24 May 1999.

The dishes remind me of big flowers pointing their petals to the skies, waiting to receive whatever's out there. There's nothing between my dish and the end of the universe.

— Rachel Tortolini, Wired magazine issue 5.01, January 1997.

Today, rock 84001 speaks to us across all those billions of years and millions of miles. It speaks of the possibility of life. If this discovery is confirmed, it will surely be one of the most stunning insights into our universe that science has ever uncovered. Its implications are as far-reaching and awe-inspiring as can be imagined.

— President Clinton, regarding the Mars meteorite, White House South Lawn, 7 August 1996.

Chances are, when we meet intelligent life forms in outer space they're going to be descended from predators.

— Michio Kaku, string theorist, City University of New York, Alien Planet, Discovery Channel TV special, 2005.

We know the number of stars in the universe is something like one followed by 23 zeros. Given that number, how arrogant to think ours is the only sun with a planet that supports life, and that it's the only solar system with intelligent life.

— Edward J. Weiler, NASA Director, Washington Post newspaper, 20 July 2008.

I suspect there could be life and intelligence out there in forms we can't conceive. Just as a chimpanzee can't understand quantum theory, it could be there as aspects of reality that are beyond the capacity of our brains They could be staring us in the face and we just Don't recognise them. The problem is that we — re looking for something very much like us, assuming that they at least have something like the same mathematics and technology.

— Lord Martin Rees, President of the Royal Society and astronomer to the Queen, the Daily Telegraph newspaper, 22 February 2010.

Sometimes I think the surest sign that intelligent life exists elsewhere in the universe is that none of it has tried to contact us.

— Calvin and Hobbes cartoonist Bill Watterson.

Imagine how foolish you would feel if you didn't try only because someone said you're a lunatic.

— Paul Horowitz, Harvard physicist and SETI veteran, Discover magazine, July/August 2010.

We stand on a great threshold in the human history of space exploration. If life is prevalent in our neighborhood of the galaxy, it is within our resources and technological reach to be the first generation in human history to finally cross this threshold, and to learn if there is life of any kind beyond Earth.

— Sara Seager, MIT astrophysicist, testimony to the US House Committee on Science, Space and Technology, 4 December 2013.

With billions of rocky worlds life would have to be extremely picky not to be able to evolve out there.

— Lisa Kaltenegger, Harvard lecturer and leader of a research group at the Max Planck Institute for Astronomy, Time magazine, 13 January 2014.

Sometimes I think we're alone in the universe, and sometimes I think we're not. In either case the idea is quite staggering.

— attributed to Arthur C. Clarke

In the deepest sense the search for extraterrestrial intelligence is a search for ourselves.

— Carl Sagan, 'The Quest for Extraterrestrial Intelligence,' Smithsonian magazine, May 1978.



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