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First, I must apologize for the typos in my post above, especialy confusing NPR and
American Public Media. I also apologize if the following is too verbose.

There has been no large-scale effort to build a beacon. SETI has focused on looking for transmissions. The exceptions are either incidental, such as the radar work at Arecibo, or intended more as a "message to back here", as Sagan described the Voyager record. The Cosmic Call Project shows the latter - their signals reach only a few stars, and last only hours.

The problem is the unknown distance to any aliens. At a minimum, aliens at all similar to us are at least four and a half lightyears away (at Alpha Centauri). Any reply arrives at least a decade after a radio signal goes out. Given arbitrary values for how often life occurs on other planets, how often intelligences develop and build radios, and how long they use them, we can estimate the distance as anything from four and a half lightyears to infinity, the latter where we are alone in the universe. This analysis was developed by Frank Drake, and is a favorite of astronomers. Typical estimates are several hundred to a few thousand lightyears, so that a beacon has no effects that we can know about for centuries. One astronomer called SETI "the archeology of the future".

There _have_ been engineering studies of beacons, especially by the SETI Institute ( Since I think in terms of numbers: for the equivalent of 100 million US dollars, we could build a beacon to reach 300 million stars, last for 1000 years without human intervention and transmit the equivalent of a single book or a constantly tended and repaired beacon that transmits the information contained in a thousand books over the same volume.

In discussions between astronomers, engineers, and members of the public, the first ethical question is "should a beacon be built?". I've heard arguments that "we are alone, so we don't need to talk", although I do not believe that myself. Another argument, perhaps based on _The War of the Worlds_, is "be quiet and the aliens won't invade". Invading a planet lightyears away is probably more trouble than it's worth, but this idea can't be discarded entirely either. An economic argument derived from the long timescale is "a beacon is a waste of resources", although when compared to some projects, 100 million is not large.

Given agreement that a beacon be built, there are more arguments. If the beacon needs people to maintain it, is there an institution to sustain them for a thousand years? Only religion and some philosophies work on such large timescales in human society.

You have asked what information should be included in the message sent by the beacon. That is a very large question, and probably generates the most debate. There are entire books of argument from when Sagan's team was assembling the Record. But before that, how can we establish a common language with someone we have never met? We can use mathematics and physics as a Rosetta Stone: start with arithmetic and work up through chemistry to biology and eventually culture and philosophy. But the details are complex, including linguistic theories of grammar and the extent to which we and any alien experience the universe the same way. All of this happens before we reach the types of questions asked by Dr. Russell.

Some other sources discussing the ethics and philosophy of SETI:

As you note above, Carl Sagan was the grandmaster of this field, both in non-fiction and fictional works. His largest discussion, the novel Contact, was developed into a movie which could not include all of the ideas.

The SETI Institute operates the largest current SETI survey, and as I described above, has considered the design of a beacon. In particular, Jill Tarter, their director of research, is active in considering the ethical aspects. Dr. Tarter was Sagan's inspiration for the heroine of the Contact story.