Abstract for the 30th Review Meeting of the SETI.
October 1-5, 2001, Toulouse, France, 2001.
RADIO SIGNALS TO EXTRATERRESTRIALS
Alexander L. Zaitsev, alzaitsev@ms.ire.rssi.ru
IRE RAS, Vedensky Square 1, 141190 Fryazino, Russia
Spectral approach is a universal tool of both astronomical observations and SETI. Furthermore, it has a clear physical meaning – spectrometer finds the energy distribution of photons, in human sensing it is color and pitch. Under the hypothesis on identity of physical laws in our part of Universe, it may be proposed that spectrometry also are using by those aliens, who know radio and lead theirs own SETI, too. Also, in order They will be able easier to conceive our spectral information, the better if it will represent the single-valued function of time. The second argument for such function is a fact of transmitter's energy concentration inside one band, which will lighten to aliens to solve their SETI Problem.
Further, there are three thinkable types of single-valued function – continuous, discrete and constant. The transmission of constant, extremely narrow spectral line may be used for information about "unknown" knowledge. In other words, if we shall transmit the signal with slow frequency drift, which accounts the Earth's rotation and our moving around Sun, in order to imitate the radio emission from the Sun's center, They definitely understand it and try to extract from such signal the useful astrophysical information about secular change of radial velocity and propagation effects in interstellar medium. Such method, also called radio sounding, now widely used in Solar System space research. And here is suggested to extend it on radio probing of Galaxy.
The second function, or transmission the spectral line, which is coherently jumping among two-three discrete positions is a well-known way to transmit the logical messages.
The third type of our spectral behavior is a show of continuous function at the alien's SETI indicator. It may be supposed that this function might be used for information about our emotional world. The most well known and easy way to express our emotional condition is music. Further, there are two main types of musical sources. The first type produces the damped oscillations, it's a piano, guitar, tam-tam, etc, and the second one produces the self-oscillation, it's a violin, organ, singing, theremin, etc. You see the second type is an adequate to a process of implementation of continuous radio signals. And the theremin is the most preferable source of space music, because it produces a quasi-sinusoidal signal with smooth frequency and continuous phase under performance, and so is better detectable across interstellar distances.
To resume, it may say that radio signal with constant frequency and so, with zero initial information uses the "language of nature" to report Them some useful astrophysical data, discrete variation is a tool of "language of logic", and continuous one may be used as an instrument of "language of emotions" in order to inform extraterrestrials about our unique inward experiences.