Cornell News: Arecibo message anniversary

Larry Klaes (
Fri, 12 Nov 1999 20:35:39 -0500

>Date: Fri, 12 Nov 1999 16:41:02 -0500
>Subject: Cornell News: Arecibo message anniversary
>X-PH: (Cornell Modified)
>X-Sender: cunews-mailbox@
>It's the 25th anniversary of Earth's first (and only) attempt to phone E.T.
>FOR RELEASE: Nov. 12, 1999
>Contact: Bill Steele
>Office: (607) 255-7164
>ITHACA, N.Y. -- Twenty-five years ago next week, humanity sent its first
>and only deliberate radio message to extraterrestrials. Nobody has called
>back yet, but that's OK -- we weren't really expecting an answer.
>The message was sent during the dedication of a major upgrade to the
>Arecibo radio telescope in Puerto Rico on the afternoon of Nov. 16, 1974,
>and contained some very basic information about the human race. It
>included representations of the fundamental chemicals of life, the formula
>for DNA, a crude diagram of our solar system and simple pictures of a human
>being and the Arecibo telescope.
>"It was strictly a symbolic event, to show that we could do it," explains
>Donald Campbell, Cornell University professor of astronomy, who was a
>research associate at the Arecibo Observatory at the time. Arecibo
>Observatory is operated by the National Astronomy and Ionosphere Center,
>managed by Cornell University for the National Science Foundation.
>The real purpose of the message was to call attention to the tremendous
>power of the radar transmitter newly installed at Arecibo and the ability
>of the telescope's 1,000-foot diameter dish antenna to project a powerful
>signal into space. But many of those present took the event seriously,
>according to Harold Craft, Cornell's vice president for services and
>facilities, who was then director of the Arecibo Observatory. "We
>translated the radio-frequency message into a warbling audio tone that was
>broadcast over speakers at the ceremony. When it started, much of the
>audience spontaneously got up and walked out of the tent and gazed up at
>the telescope."
>While the audience that had gathered beside the huge Arecibo dish was
>impressed by the idea of sending messages to space, others were critical.
>Some actually suggested that sending such a message was dangerous, because
>it might attract the attention of hostile aliens.
>They probably needn't have worried. The chance that the message might
>actually be detected by some extraterrestrial intelligence is extremely
>small. It was sent only once, over a period of about three minutes, on a
>narrow beam directed toward a group of about 300,000 stars called the Great
>Cluster in Hercules, Messier 13. The globular cluster is 25,000
>light-years away in our galaxy, the Milky Way. So far, moving at the speed
>of light, the message has traveled only one thousandth of the distance, or
>about 147 trillion miles. There are stars closer to our solar system than
>that, but none of them is in the path of the message.
>Ironically, the globular cluster at which the signal was aimed won't be
>there when the message arrives. It will have moved well out of the way in
>the normal rotation of the galaxy. But "anyone" in the target area when the
>signal arrives, they could detect it with a radio telescope of similar
>size, and it would appear at 10 million times the intensity of the normal
>radio signals from our sun. From there, the message will continue on its
>course through outer space, ultimately, millions of years hence, reaching
>distant galaxies.
>Since the transmitter was installed in 1974, Arecibo radar has been used
>for extensive explorations of the solar system, including detailed mapping
>of the surfaces of the moon and Venus. The radar was upgraded to even
>higher power in 1997. No other formal messages have been sent, but many of
>the radar signals have continued on out of our solar system and if detected
>would clearly be seen as created by intelligent beings, Campbell says. In
>addition, a message, engraved on copper plate, accompanied the Pioneer 10
>spacecraft launched in March 1972 and now is about 7 billion miles from
>Meanwhile, researchers constantly use the huge dish antenna to listen for
>signals from alien intelligence. One project, known as Phoenix, aims the
>telescope at specific stars; another, called Serendip, collects data on
>certain likely frequencies during all the telescope's other operations, and
>distributes the data to thousands of volunteers to process on personal
>computers. Project Phoenix is directed by the non-profit SETI Institute,
>based in Mountain View, Calif. Serendip is a project of the University of
>California at Berkeley.
>The 1974 message was transmitted on a frequency of 2380 MHz and consisted
>of 1,679 binary bits representing ones and zeros, sent by shifting the
>frequency of the signal up and down over a range of about 10 Hz, a method
>similar to that used by computer modems to send binary code over a
>telephone line. If the ones are translated into graphics characters and
>the zeros into spaces, the message forms a symbolic picture 23 characters
>wide by 73 long.
>The content of the message was developed by Frank Drake, then professor of
>astronomy at Cornell and now a professor in the Division of Natural
>Sciences at the University of California at Santa Cruz and president of the
>SETI Institute; Richard Isaacman, then a Cornell graduate student and now
>working at Research and Data Systems Corp. in Greenbelt, Mass.; Linda May,
>another graduate student now professor of physical sciences at Wheelock
>College in Massachussetts, and James C.G. Walker, then a member of the
>Arecibo staff and now professor of physical sciences at the University of
>Michigan at Ann Arbor. Others, especially the late Carl Sagan, who
>eventually became the David Duncan Professor of Astronomy and Space
>Sciences at Cornell, contributed to the project.
> Related World Wide Web sites: The following sites provide
>additional information on this news release. Some might not be part of the
>Cornell University community, and Cornell has no control over their content
>or availability.

> --The Arecibo web site: <>
>-- Cornell News Service coverage of the most recent Arecibo upgrade:
>-- The SETI Institute: <>
> -- Profile of Jill Tarter, director of Project Phoenix:
> <>
>The web version of this release, with accompanying graphic, may be found at
>Cornell University News Service
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