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Cosmic Decoders: Exchanging Messages with Alien Civilizations

A Resource Guide

by Andrew Fraknoi
(Foothill College)
[Version 1.1; December 2003]

As humanity actively searches for messages from other civilizations among the stars, both physical and social scientists have begun to give some thought to the form that their message and our answer might take. In other words, how will they “speak” our language, and how will be reply in theirs? Below are some print and web resources to help you explore what people have been thinking in this area, together with a few general references on the scientific search for extra-terrestrial intelligence (SETI).

1. Articles about Messages We Might Find or Send

Vakoch, D. “The View from a Distant Star: Challenges of Interstellar Message Making” in Mercury (the magazine of the Astronomical Society of the Pacific), Mar/Apr. 1999, p. 26. (A nice review article; on the web at:

Interstellar Message Construction Web Pages at the SETI Institute (good source to start with; includes articles, interviews, and some history):

Links to Web Sites about Interstellar Communications (Kept by NASA’s Mike Matessa, this comprehensive guide to web sites includes messages already sent, practice messages, and future message ideas):

CETI: Active SETI Site (Two Canadian scientists suggest some messages and encourage readers to decipher them):

Vakoch, D. “Altruism: A Scientific Perspective” (from the Sep/Oct. 2001 issue of Science & Spirit): (Considers how we might let aliens know that we are not just selfish, but can practice altruism.)

2. Books about Messages We Might Find or Send

Benford, Gregory Deep Time: How Humanity Communicates Across the Millennia. 1999, HarperCollins. One section of this fascinating book on long-term communication is the story of how an innovative message was planned for, but then not sent with, the Cassini spacecraft exploring the Saturn system.

McConnell, Brian Beyond Contact: A Guide to SETI and Communicating with Alien Civilizations. 2001, O’Reilly. A telecommunications engineer looks at possible messages we might exchange with aliens in some detail. (This is a book for those who like math and puzzles.)

Regis, Edward, ed. Extraterrestrials: Science and Alien Intelligence. 1985, Cambridge University Press. This collection of articles on the implications and likelihood of contact includes three articles on messages between civilizations (including one by Marvin Minsky.)

Vakoch, Douglas, ed. Between Worlds: The Art and Science of Interstellar Message Composition. 2004, MIT Press. A forthcoming collection of papers from a 2002 conference held in Paris about messages. (Technical) You can read some of the abstracts at:

3. Books and Articles about Earlier Messages

Dick, S. The Biological Universe: The 20th Century Extra-terrestrial Life Debate. 1996, Cambridge U. Press. A history of recent thought about SETI with sections on earlier messages and the first thoughts scientists had about using pictures for messages.

Sagan, C., et al. Murmurs of Earth: The Voyager Interstellar Record. 1978, Random House. All about the contents and planning for the video and audio record (“the sights and sounds of Earth”) carried aboard the two Voyager spacecraft, which have now left the solar system.

“Messages from the Moon, to Mars, to the Stars” (a nice introductory article on the history of SETI messages by Douglas Vakoch of the SETI Institute):

Vakoch, D.: The Martian Morse Code Challenge (introduces early ideas about using simple codes to communicate):

Vakoch, D. Messages from ET (Part 1) — about an earlier message devised in the 1960’s by astronomer Frank Drake; part 1 shows the message and asks if you can figure it out:

Vakoch, D. Messages from ET (Part 2) — part 2 explains Drake’s sample message:

The Arecibo Message: (In 1974, humanity sent its first coded message into space, using the giant radio telescope at Arecibo, Puerto Rico. At this site, you can view the message in various forms, and see if you can figure it out, before jumping to another page with the answer.)

The Voyager (audio-video) Record:
(The two Voyager spacecraft, now on their way to the stars, carry a record that has the “sights and sounds” of Earth on it.)

4. A Few Good Books about SETI in General

Drake, Frank & Sobel, Dava Is Anyone Out There: The Scientific Search for Extraterrestrial Intelligence. 1992, Delcorte Press. Well-written autobiography of Frank Drake, the pioneer scientist in this field, with good background information on the search.

Goldsmith, Donald & Owen, Tobias The Search for Life in the Universe, 3rd ed. 2001, University Science Books. The definitive college textbook on this topic. (Chapter 20 is about messages.)

Harrison, Albert After Contact: The Human Response to Extra-terrestrial Life. 1997, Plenum. A psychologist analyzes what finding life out there might mean for our thinking on Earth.

Lemonick, Michael Other Worlds: The Search for Life in the Universe. 1998, Simon & Schuster. Time Magazine’s senior science correspondent summarizes new ideas and discoveries in the SETI arena.

Shostak, Seth Sharing the Universe: Perspectives on Extraterrestrial Life. 1998, Berkeley Hill. Popular-level thought-provoking essays on the implications of SETI by one of the scientists involved.

Shostak, Seth & Barrett, Alex Cosmic Company: The Search for Life in the Universe. 2003, Cambridge University Press. A new book introducing SETI for beginners.

Swift, David SETI Pioneers. 1990, University of Arizona Press. In-depth interviews with a number of the leading scientists in the SETI field.

Webb, Stephen If the Univere is Teeming with Aliens…Where is Everybody? (50 Solutions to the Fermi Paradox). 2002, Copernicus/Springer Verlag. The great physicist Enrico Fermi wondered one day why, if life out there is common, aliens were not visiting us. Here are many interesting possible answers to his question.

Billingham, J., et al., eds. Social Implications of the Detection of an Extraterrestrial Civilization. 1994, SETI Press, SETI Institute, 2035 Landings Dr., Mountain View, CA 94043. This more scholarly, but interesting, report describes the thinking, during a series of workshop that considered how humanity would be affected if we did discover intelligent life out there.

5. A Few Selected Articles about SETI in General

LePage, A. & MacRobert, A. “SETI Searches Today” in Sky & Telescope, Dec. 1998, p. 44. On the scientific searches for signals from other civilizations. (An updated version is kept on the Web at: )

Sagan, C. “The Search for Extraterrestrial Life” in Scientific American, Oct. 1994, p. 93. Part of an entire issue devoted to how the universe evolved to make life like us possible.

Shilling, G. “The Chance of Finding Aliens: Re-evaluating the Drake Equation” in Sky & Telescope, Dec. 1998, p. 36.

Shostak, S. “When ET Calls Us” in Astronomy, Sep. 1997, p. 36. What do we do when we receive a message.

Shostak, S. “The Future of SETI” in Sky & Telescope, Apr. 2001, p. 42. A nice long review article on new searches and new strategies.

Tarter, J. & Chyba, C. “Is There Life Elsewhere in the Universe?” in Scientific American, Dec. 1999, p. 118. A review of scientific thinking about both intelligent life and life in general out there.

Tough, A. “How to Achieve Contact: Five Promising Strategies” on the web at: An analysis of ways we might find out about intelligent life out there.

Archive of Columns on SETI (written for by the scientists at the SETI Institute, in clear accessible language):

6. Web Sites about SETI in General

SETI Institute: (The Institute is the premier organization involved with the search for intelligent life elsewhere and its site is full of good information at many different levels.)

Sky & Telescope Magazine SETI Articles: (This site from one of the two main astronomy magazines has a number of useful articles.)

The Planetary Society SETI Pages: (Has information about various projects sponsored by this politically active organization that encourages scientific exploration.)

The SETI League: (This organization consists of people around the world doing SETI searches as a hobby.)

7. Some Science Fiction Stories With A Realistic Portrayal of SETI

Gunn, James The Listeners. 1972, Signet. Good early portrayal of a scientifically reasonable search.

McDevitt, Jack The Hercules Text. 1986, Ace. Flawed, but interesting novel about radio communication with a distant civilization.

Sagan, Carl Contact. 1985, Simon & Schuster.The discovery of radio signals from extraterrestrial intelligence leads humanity to re-evaluate its self-image. The heroine is loosely based on Jill Tarter, the scientist who leads one of the major scientific searches for signals today.

Sawyer, Robert Factoring Humanity. 1998, Tor. A radio message from the direction of the nearby star Alpha Centauri helps humanity get in touch with both another civilization and itself.

Spinrad, Norman “The Helping Hand” in Full Spectrum 3,ed. Lou Aronica, et al., 1991, Bantam. An alien message unites humanity, but turns out to be a benevolent lie.

Zerwick, C. & Brown H. The Cassiopeia Affair. 1968, Curtis. An exploration of the effects that an alien radio message might have on Earth. One of the authors is a geochemist.