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Calling Et, Or Not Even Answering the Phone? Calling ET, or JBIS,Not Even Vol. Answering 67, pp.xxx-xxx, the Phone? 2014 CALLING ET, OR NOT EVEN ANSWERING THE PHONE? ALEXANDER L. ZAITSEV Institute of Radio Engineering and Electronics, Prospekt Mira 24/2 - 117, 141196 Fryazino, Russia. Email: [email protected] The complex query (in the Title) can be divided into two more simple questions: To Send or not to Send? (“Calling”) and To Answer or not to Answer? (“Answering”). The second question will be vital maybe tomorrow morning (if the SETI-signal was detected) or maybe never. And in any case, such answering requires a careful analysis of any ET-message received. The first question is quite suitable and feasible for analysis right now. There are two ‘pro’ arguments: Asteroid Hazard and Loss of Interest. Keywords: Extraterrestrial intelligence, SETI, METI, interstellar flight, active SETI, contact 1. THE ISSUES TABLE 1: Asteroid Hazards: Residuals for Several NEO (Near-Earth Object) Orbits Using Optical Data (O) and Also This complex subject can be divided into two simple questions: for an Orbit Using Both Radar and Optical Data (O + R). • To Send or not to Send? (“Calling”) Object O O + R O/(O + R) • To Answer or not to Answer? (“Answering”) 4769 Castalia 24" 0.4" 60 o o The second question will be vital either tomorrow morning 1991 AQ 57 0.1 380 (if the SETI-signal detected), or maybe never. And in any 6489 Golevka 3600" 4.6" 780 case, answering requires a careful analysis of any ET-message 1986 JK 114o 0.1o 910 received. However, the first question is quite suitable for unambiguous analysis right now. Also such kind of real human activity, as calling (or messaging) is quite feasible right now. Therefore, I would like to offer two ‘pro’ arguments: Asteroid Hazard (Table 1) and Loss of Interest. You can see the key role of radar astrometry in identification of dangerous NEOs – we have no other methods for it. Thus, we cannot forbid using and sending powerful radar signals! And it is very important to understand: both NEO Radar Research and Messaging to ETI are using the same powerful instruments: Arecibo Radar Telescope (ART), Goldstone Solar System Radar (GSSR), and Evpatoria Planetary Radar (EPR). 2. RADAR ASTRONOMY TRANSMISSIONS VERSUS MESSAGING TO ETIS Fig. 1 Angular space of asteroid and planetary radars from Earth. As to the danger related to transmission of interstellar radio the size of stars and “belts of a life” around the stars. Therefore messages (IRMs), a careful analysis shows that the pointed at pointless casual radiation transmission the probability radiation of IRMs sent using planetary and asteroid radar of getting into inhabited zones is insignificantly small. It telescopes, apparently, is not as dangerous as pointless is important to mention the following feature of the radar transmissions of the same radars. Figure 1 indicates all observations of Solar system bodies: a slow scanning over the transmissions during radar observations of planets, asteroids celestial sphere that is related to the proper motion of targets of and comets. the radar observation. From this fact two important conclusions follow. First, this may explain why we do not detect any radar Analysis of radar data has revealed the following signals from other civilizations. Ostro and Sagan explained the experimental fact: any among the 1223 transmissions does absence of signals from Their radar telescopes by the idea that not get to stars [1]. This means that the interstellar space is They may not use radar astronomy and, consequently, are not almost empty; the distance between stars is much greater than protected against asteroid or comet hazard. We have another, This paper was presented at the Royal Society Satellite Meeting rather reasonable explanation. If the probability of our radar ‘Towards a Scientific and Societal Agenda on Extra-Terrestrial Life’, transmissions to get into the habitable zones of cataloged stars Kavli Center, Chicheley Hall, UK, 4-5 October 2010. is very low and They do not see us, then the probability to get 1 Alexander L. Zaitsev to the Earth at similar pointless transmissions implemented by other civilizations is also very low. For this reason, we also do not see Them. The second, not less essential conclusion from that fact that any of our 1223 transmissions have not gotten into a habitable zone of Type I civilizations when the radar beams slowly scan the sky, illuminating greater areas of the Galaxy, consists that such radiation is much easier to be detected by those unknown aggressive and super-power civilizations which scare so much the METI opponents. In this sense rare pointing transmissions of interstellar radio messages represent considerably smaller danger than numerous addressless radar astronomy transmissions. There are two reasons for that. First, IRMs are precisely directed to target specific stars, and, second, the radar beam is motionless relatively to other stars and, hence, during radiation does not scan and does not illuminate the celestial sphere (Fig. 2). An estimate of this is ratios of fluence from and times of the transmissions is SRADAR/SMETI ~ 2000, TRADAR/TMETI ~ 500, where S is the total area of the sky, illuminated by transmissions and Fig. 2 Angular space of radio messages from Earth. T is the total duration of both transmissions. Therefore, the probability to detect the radar astronomy transmissions by a hostile super-civilization is in (2000 × 500) = 1,000,000 times higher than that of the METI transmissions. And it is very important to understand: “addressless” RADAR transmissions and targeted METI are absolutely equivalent, because monster super-aggressive and super- powerful ETIs may live anywhere. It is clear that a ban on radar investigations of small solar- system bodies would make it impossible to provide a protection against asteroid and comet hazard. Moreover, there is rapid growth in the number of new radar detections of asteroids and comets, Fig. 3, and this tendency will grow even stronger when more powerful and dedicated asteroid and comet radar systems are created (Fig. 4). This will result in more complete coverage of the celestial sphere by terrestrial power electromagnetic radiation. 3. RADAR ASTRONOMY PROGRESS Fig. 3 Growth of asteroid and planetary radars from Earth. Probability of detection of the Earth because of radiation of powerful radar signals tends to increase in time. And also you Fig. 4 Future growth of asteroid and planetary radars from Earth. can draw the conclusion that struggle against mythical ET-threat by prohibition of any power Radar Astronomy transmission creates real asteroid threat! 4. LOSS OF INTEREST Sebastian von Hoerner was the first, who in the 1960s indicate that “Loss of Interest” represents real cause of extinction of advanced Civilization. In Russian is the word “odinochka”, which corresponds to “one-man cell” in English. Prohibition of interstellar transmission converts the Earth into “one- civilization cell”. I think that it is not INTERESTING for inhabitants to live in such enforced self-isolation, in such lurker-like Civilization! We cannot speak for all, but we do not want to live in a cocoon, in “one-man cell”, without any rights to send a message outside, because such life is not INTERESTING! Civilizations forced to hide and tremble because of farfetched fears are doomed to extinction. 2 Calling ET, or Not Even Answering the Phone? Summing up, we can conclude that the struggle against CONCLUSIONS one mythical ET-threat by prohibition of any power Radar Astronomy transmission and Messaging to ETI creates two Finally, “weighty arguments” adduced by creator and adduced real problems: defenselessness in the face of Asteroid Hazard by critic possess different weight. To create ET radio message and the threat of very probable extinction such self-isolated or to allow its transmission, one must be a professional, but to civilization due to “Loss of Interest” [2, 3]. destroy or prohibit it is quite enough to be a dilettante. REFERENCES 1. A. Zaitsev, “Sending and Searching for Interstellar Messages”, Acta www.setileague.org/editor/meti.htm. (Last Accessed 11 March 2014) Astronautica, 63, pp.614–617, 2008. 3. A. Zaitsev, “Rationale for METI”, http://arxiv.org/abs/1105.0910. (Last 2. A. Zaitsev, C.M. Chafer and R. Braastad, “Making a Case for METI”, Accessed 11 March 2014) (Received 14 February 2014; Accepted 17 February 2014) * * * 3.
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