THE SEARCH FOR EXTRATERRESTRIAL INTELLIGENCE (SETI) IN THE OPTICAL SPECTRUM AND A RARE VISIT BY ARTHUR C. CLARKE TO THE UNITED KINGDOM From the author of the January 1992 EJASA article (EJASAV3.N6A - EJASAV3.N6F) on Optical SETI who is presently in England. This message has been sent from UCL (U.K.) via telnet to OSU (U.S.) and is being posted to sci.space, sci.astro, rec.video.satellite and other newsgroups. The following Optical SETI talks have been arranged in the United Kingdom: (a) Venue: King's College, Strand, London WC2R 2LS, Room 2C. Date: Wednesday, June 17, 1992. Time: 5.30 - 6.30 pm. Sponsor: British & Ireland Chapter of the IEEE. For further information, contact Professor A.C. Davies at King's College (071-873-2441) or Dr. S. A. Kingsley. (b) Venue: Loughborough University of Technology, Loughborough, Leicestershire, LE11 3TU, Lecture Theatre WW01. Date: Wednesday, June 24, 1992. Time: 7.30 - 8.30 pm. For further information, contact Professor Nicholas J. Phillips in the Physics Department at Loughborough University (0509-223303). There may also be a talk at University of Southampton, Department of Electronics, Highfield, Southampton S09 5NH on June 9, 10, 11 or 12. For further information, contact Dr. John P. Dakin (0703-593085). For further information about any of the above talks, call Stuart Kingsley on 081-800-6152 (London) or 0202-296377 (Bournemouth). I am off to Bournemouth on Wednesday for about twelve days (June 3 - June 15), so my next message won't be till after June 15. A short description of these talks (which has been posted previously) now follows: THE SEARCH FOR EXTRATERRESTRIAL INTELLIGENCE (SETI) IN THE OPTICAL SPECTRUM by Dr. Stuart A. Kingsley Summary Over the years, the Search for Extra-Terrestrial Intelligence (SETI) has generated a lot of controversy both within and outside the scientific community, not least because so far the "search" has been without success. The conventional wisdom since the 1959 classic paper by Cocconi and Morrison on Searching for Interstellar Communications, has been that the radio frequency spectrum, particularly the quietest region of the electromagnetic spectrum at or near the 21-cm hydrogen line, would be the best place to look for signals. This region of the microwave spectrum between the H and OH resonance lines (1.420 - 1.612 GHz) is known as the water-hole. On October 12 (Columbus Day), the SETI Community starts the search phase of the Microwave Observing Project (MOP). It is therefore an auspicious moment to reassess the rationale for SETI. This lecture re-examines the case for conducting the "search" in the optical region of the spectrum, even though quantum noise and doppler shifts are substantially greater at optical frequencies. It also demolishes the argument put forward by the late Asimov and others, that it is not possible to "see" an extraterrestrial laser transmitter with the light of its star in the background. Despite these so-called problems, it is shown that the gain afforded by the high ratio of antenna diameter to wavelength, more than makes up for these deficiencies. Such transmitters/ receivers are substantially smaller than their microwave counterparts, and are thus also ideal for communication links for deep space probes and spaceships. No claim is made that the idea of Optical SETI is in anyway original. Indeed, it was first suggested by Schwartz and Townes (1964 Nobel laureate for the laser) nearly 30 years ago in their paper "Interstellar and Interplanetary Communication by Optical Masers". However, Dr. Kingsley finds it perplexing that the SETI community has largely ignored the optical approach, and would have the general public believe that ETIs would not use lasers for interstellar communications. On a transmitter power basis, the optical approach to SETI produces greater signal-to-noise ratios and permissible data-rates than is possible with microwaves. Thus, one conclusion drawn is that present- day SETI receivers may well be tuned to the wrong frequencies. Space-deployed Professional Optical SETI Observatories using optical heterodyne receivers or coherent ground-based receivers with adaptive optics, should allow for the transmission of high data-rate signals over distances in excess of 1000 light years. By definition, most technical extraterrestrial civilizations will be more advanced than our own, and be capable of producing very powerful continuous-wave or pulsed signals. It is thus further proposed that Amateur Optical SETI is both feasible and an affordable activity for amateur astronomical societies and clubs. The design, performance and cost of such an Amateur Optical SETI Observatory will be described. Biography Dr. Stuart Kingsley was born in Stoke Newington in 1948 and grew up in South Tottenham. He has a B.Sc. and Ph.D. in electrical engineering from London's City University, and University College, respectively. Stuart is a Member of the IEE and Senior Member of the IEEE. He moved to the United States and Columbus in 1981, and joined Battelle Memorial Institute to lead their fiber-optic sensing activities. In 1984, he shared with his Ph.D. advisor Professor D.E.N. Davies, the prestigious Rank Prize for Optoelectronics. This was awarded for their fundamental work in the development of fiber-optic sensing technology. Since 1987, Stuart has been an independent consultant, specializing in fiber-optic sensing, photonic communications systems, lighting/VDU flicker, possible electromagnetic health hazards, and the optical search for extraterrestrial intelligence. -------------- Recently, I have been having some correspondence with Arthur C. Clarke concerning Optical SETI. Arthur is visiting his family home in Somerset, England in July. The following is extracted from advertizing flyer for a program arranged by his brother Fred Clarke: MINEHEAD Space Age Festival 18-26 July 1992 Celebrating British Industry Space year, 75th birthday of Arthur C. Clarke, CBE (born in Minehead), the International Year of Space. SPECIAL EVENTS: MINEHEAD SPACE AGE EXHIBITION Market House Lane, off The Parade. Open daily 10 a.m.- 6 p.m. A PROGRAMME OF TALKS BY GUEST SPEAKERS At the Regal Theatre: Patrick Moore, CBE, on space music; John Brunner on science fiction; Neil McAleer on his new biography of Arthur C. Clarke, CBE, who will be present; Mat Irvine on model making and special effects for TV and films [Matt is a very active member of ASH and his name may often been seen in the credits at the end of BBC science fiction programs like Dr. Who]; artist David A. Hardy, FBIS, on space painting; Dr. Duncan Steel, of Australia, on Spaceguard - the detection of asteroids from outer space; Fred Ordway (USA) and Harry Lange on the making of the film "2001 - A Space Odyssey". Also at the Regal Theatre: "Watch This Space" - an evening of entertainment by Minehead Amateur Theatrical association on a space theme, including a short play, music, videos, sound and light presentations, and a reading by Arthur C. Clarke, CBE. At the library: Talk by Terry Prachett, fantasy writer - "Truckers, Discworld", etc. PAINTING EXHIBITION AND COMPETITION at the Church Institute, Banks Street, open daily 10 a.m. - 6 p.m. Space age paintings and displays by local artists and Peter Pracownik and Paul Marsh. On the Seafront: ELECTRIC TIME TRAVEL An audio-visual experience and exhibition presented by SWEB. Regular shows daily, admission free. Minehead Space Age Festival, organised by Minehead Town Council. POSTER Sponsored By SWEB Full programme available from Tourist Information Centre, 17 Friday Street, Minehead. Tel. 0643-702624. Watch out for. . . . A FAILED RECLUSE HTV Friday 17th July 1992 at 22.40 hrs A 30 minute documentary feature on ARTHUR C. CLARKE'S links with Minehead. Produced by Serendipity Picture Company. Date: June 2, 1992 File: TALKS_UK.JUN Dr. Stuart A. Kingsley, CEng, Consultant, MIEE, SMIEEE, The Planetary Society, Space Studies Institute, Columbus Astronomical Society, Volunteer, SETI Group, Ohio State "Where No Photon Has Gone Before & The Impossible Takes A Little Longer" __________ FIBERDYNE OPTOELECTRONICS 545 Northview Drive Columbus, Ohio 43209 United States Tel/Fax: (614) 258-7402 Manual Fax Tone Access Code: 33 Bulletin Board System (BBS): Modem: (614) 258-1710, 300/1200/2400/4800/9600 Baud, MNP, 8N1. Email: skingsle@magnus.acs.ohio-state.edu CompuServe: 72376,3545