Xenology: An Introduction to the Scientific Study of Extraterrestrial Life, Intelligence, and Civilization

First Edition

© 1975-1979, 2008 Robert A. Freitas Jr. All Rights Reserved.

Robert A. Freitas Jr., Xenology: An Introduction to the Scientific Study of Extraterrestrial Life, Intelligence, and Civilization, First Edition, Xenology Research Institute, Sacramento, CA, 1979; http://www.xenology.info/Xeno.htm


24.3.1  Why Probes Are Better

While penurious planetary Type I societies may only be able to afford radio wave communications, we have already pointed out that technically sophisticated civilizations (whose technologies realize theoretical maxima in matter-energy systems) should view signals and probes as energetically indistinguishable alternatives for interstellar communication. Both may be used by advanced Type II or Type III cultures, for a variety of different purposes and functions. But energy efficiency cannot be used to distinguish the two choices when maximum technology is available. We must look elsewhere for distinguishability criteria.

The author believes that probes are probably the method of choice for technically advanced civilizations. In support of this position, he would like to offer several criteria which he believes argue persuasively for the inherent superiority of starprobes in interstellar communication.

First, there is the issue of communications feedback. A probe which discovers a garrulous inhabited world may engage in true conversation with the indigenes, an interchange and interweaving of cultures. Interactive exchanges may take fractions of a second between questions and answers. On-site starprobes, perhaps in orbit around the host’s sun or planet, can carry on real-time educational and linguistic functions with a precision no remote signaling system can match. As an added benefit, such intelligent devices would provide a noise-free channel of communication on any frequency of the contactee's own choosing. By comparison, the traditional beacon scenario appears little more than a sterile data swap requiring millennia for each cycle rather than milliseconds. With photonic transmissions, different sentient species cannot really converse.

Second, there is the question of acquisition efficiency. A beacon may radiate useful energy and information out into space for centuries, millennia, or even longer without getting any response. This energy, since it was detected by no receiver, essentially was wasted and constitutes pure economic loss for the sending society. Such a scheme necessarily assumes an inordinate (and possibly selectively disadvantageous) degree of generalized altruism on the part of the transmitting culture. Starprobes, on the other hand, become independent agents as soon as they are launched. There is no further need for energy expenditure by the transmitting society. Sophisticated messenger probes will be self-repairing, self-programming, and capable of refueling or recharging at every port of call. They can wait patiently in orbit for hundreds or even millions of years, waiting for the emergence of a communicative culture on suitable planets in the system; alternatively, they may hop from star to star until they find communicative lifeforms, and then enter into an exchange at no further cost to the original transmitting society. A subsidiary but nonetheless important benefit of starprobes is that they may function as "cosmic safety deposit boxes" for the cultural heritage of the contacting civilization. If the transmitting society is destroyed or the culture perishes for whatever reasons, the starprobes they sent to other worlds can still tell their story to any willing ears for perhaps geological time periods thereafter.

Third, there is the overwhelming advantage of military security for the transmitting race. Interstellar beacons are an invitation to disaster at the hands of unknown predatory alien civilizations. In any situation involving contact via signals, the transmitting society has given away the position of its home star system at great risk for mere speculative benefits. This terrible breach of military security may be remedied by using starprobes instead of signals. If local intelligent activity is detected by a probe in orbit around a target star, the machine may open contact with the indigenous technical species without ever having to disclose the whereabouts of its creators. If it is necessary for the starprobe to report what it has learned to the transmitting society from time to time, this easily may be accomplished in a manner which is virtually impossible to trace or to decode (e.g., by relaying trapdoor-function-encoded data through a series of widely dispersed and complexly organized repeater stations). In other words, starprobes can safeguard security in an exchange between alien societies.*

For these and many other reasons (see Chapter 17), more and more xenologists are beginning to view the interstellar messenger probe as the preferred mode of communication among extraterrestrial civilizations. (See Benford,3270 Betinus,3156 Bracewell,1041,1040,80 Clarke,3230 Forward,718 MacGowan and Ordway,600 and Niven.231)


* To guarantee the physical security of both races (host and visitor), perhaps each should send a probe to some common neutral meeting place far from the home star of either civilization. The two starcraft could then rapidly interrogate each other, interactively exchange information, and then move off and report back the results to their respective creators without risk. For the contact, a meeting site should be chosen that is known and accessible to both parties but which itself harbors no life (or only insignificant lower forms that pose no threat). Examples might include nearby O or B stars, local pulsars or black holes, white dwarfs, giant or supergiant suns, or very young solar systems located between the two potentially communicative alien civilizations.


Last updated on 6 December 2008