Contact is a science fiction novel written by Carl Sagan and published in 1985. Some of Sagan's character traits are evident in the main character, Ellie Arroway, and the novel serves as an entertaining platform in which he encapsulates ideas surrounding many of his life's interests.

A film adaptation of Contact, starring Jodie Foster, was released in 1997.

Plot summary

Warning: Spoilers follow.

Ellie is the director of "Project Argus", in which scores of radio telescopes in New Mexico are used to intensely search the skies for evidence of extra-terrestrial intelligence.

Before long, the project does, indeed, discover the first confirmed communication from extraterrestrial beings, a repeating series of the first 261 prime numbers. (A sequence of prime numbers is a commonly predicted first message from alien intelligence, since mathematics is considered a "universal language", and it is conjectured that algorithms that produce successive prime numbers are sufficiently complicated so as to require intelligence to implement them.) Further analysis of the message reveals that two additional messages are contained in different forms of modulation of the signal. The second message is a primer, a kind of instruction manual that teaches how to read further communications. The third is the real message, the plans for a machine that appears to be a kind of highly advanced vehicle, with seats for five human beings.

A subplot has Ellie interacting with a pair of Christian preachers, and informally debating God's existence. Applying the scientific method to a non-scientific subject, she states that "there isn't compelling evidence that God exists...and there isn't compelling evidence that he doesn't."

Warning: Stop reading now if you don't want to know how it ends.

Ultimately, a machine is successfully built and activated, transporting five passengers—including Ellie—through wormholes to a place near the center of the Milky Way galaxy, where they meet the senders of the message, and have many of their questions answered. Upon returning to Earth, the passengers discover that what seemed like many hours to them passed by in only fractions of a second on Earth, and that all their video footage has been erased, presumably by some phenomenon in the vehicle. They are left with no proof of their stories, and are accused of fabrication.

Thus, though she has traveled across the galaxy and actually encountered extraterrestrial beings, she cannot prove it.

In a kind of postscript, Ellie, acting upon a suggestion by the senders of the message, programs a supercomputer to compute the digits of &pi to record lengths, and to analyze the stream of numbers for a non-random pattern. Very, very far from the decimal point, she finds that a special, statistically near-impossible pattern does exist. It is an unmistakably intelligent artifact, "the artist's signature", woven into the fabric of space.

Conclusion

Sagan's only novel allows the reader to plausibly experience, in the imagination, what he longed to experience in real life: the discovery of extra-terrestrial intelligence. Also, the novel ends with the heroine finding proof of "an intelligence that antedates the universe"; Sagan himself dearly wished, and failed, to find undeniable proof of God's existence. (This should not be taken to imply that Sagan wanted to believe in God. Sagan seems simply to have wanted proof in general, and especially so for God since the ramifications would be so great. According to Ann Druyan, his widow, he "never wanted to believe. He wanted to know.")