Inaudible and invisible to humans, transmissible to distant stars at radio frequencies, interstellar messages can be understood as conceptual art. Because of the intangible nature of interstellar messages, the concepts communicated are more important than the physical translations used to convey these ideas to human viewers. And yet, broad-based, international discussion is a prerequisite to actual transmission from Earth, at least if we follow current policies advocated by the Search for Extraterrestrial Intelligence (SETI) community.

The SETI Institute's program in interstellar message composition addresses some of the most critical questions humankind will face if we detect extraterrestrial intelligence: Should we reply? If we do, what should we say? How can we create messages that would be understood on other worlds?

Even an interstellar language that has its basis in a behavioristic, rationalistic, mechanistic account of human interactions might provide a foundation for conveying aspects of the subjective experience of being human--both as an individual and as a social being.

Through analogy, sexual reproduction is illustrated by combining half of the genetic material from each of two parents to form a new individual. Complex family relationships are explained by showing the degree of shared genetic material, describing relationships within and between generations of beings with finite lives. The biological basis of some acts of altruism can also be illustrated. For example, as a predator approaches, the altruist might give a warning call, alerting its relatives but making itself a more likely target for predation. Though the altruistís likelihood of surviving to reproduce is reduced, its inclusive fitness is improved by protecting relatives that share some of the altruistís genes. Individuals in these scenarios can be represented in various ways in interstellar messages

For example, Freudenthal's Lincos provides accounts of humans performing rational cognitive functions and having awareness of these activities; it also introduces basic physical descriptions of time and space. By shifting the focus of interstellar messages from this sort of objectifying, external account of human actions to the subjective experience of finite beings aware of their own limitations, whose individual identities are both distinct from and yet dependent upon relationships with others, one might even provide accounts of authentic and inauthentic modes of existence potentially comprehensible to extraterrestrial beings.

For example, Freudenthal provided accounts of humans who are aware of facts about the external world and the passage of time. One might equally well describe humans who are aware of the inevitability of their own deaths and the impact this awareness can have on fostering more authentic relationships with others, including the freedom to choose to benefit others even at an expense to oneself.

Short-lived intelligence may seem quite alien to artificial or enhanced extraterrestrial intelligence, who may have life spans of thousands or millions of years. Our vulnerabilities living in time are used to introduce notions of altruism. We begin by describing physical objects likely to be known on other worlds as well as on Earth: chemical elements and molecules, the latter communicated both through the atoms comprising them and through their three-dimensional structures. Rather than relying solely on structural or numerical descriptions of elements and molecules, they are also signaled through icons that physically resemble the radiation patterns associated with these chemical constituents, providing a more phenomenologically direct representation of these possibly universal concepts

Framing interstellar messages as art projects is a recent development. The Search for Extraterrestrial Intellligence, or SETI, has been conducted by scientists and engineers, with minimal input from the artistic community. With advances in search technology, the chances of detecting extraterrestrial intelligence are improving rapidly. In recognition of these increasing prospects of success, the SETI Institute and Leonardo/The International Society for the Arts, Sciences and Technology (ISAST) have initiated a series of workshops to encourage discussion between artists, scientists, and technologists about interstellar message composition. Interstellar messages have not typically been construed as works of art themselves, but art and music have played a minor role in the theory and practice of interstellar message construction. For example, German astronomer Sebastian von Hoerner has suggested that some aspects of music may be universal, and two Voyager spacecraft included samples of Earth’s music. Indeed, the intrinsic temporality of radio transmissions lends itself particularly well to messages that share some of the structural characteristics of music. Such a strategy stands in contrast to traditional methods of constructing interstellar messages based on classical information theory. American physicist Lui Lam suggested sending messages based on the Sierpinski gasket, a simple fractal based upon a never-ending series of triangles within triangles, specifiable with a few lines of computer code and manifest in a range of terrestrial cultures. This general approach of tapping into potentially universal aspects of mathematics and physics was suggested for messages inspired by both visual arts (Deihl) and music (Kaiser). Conversely, Dutch astronomer and theoretical computer scientist Alexander Ollongren suggested the use of music to help clarify an interstellar language based on principles of logic .

A handful of interstellar messages have already been broadcast, represented by Russian astronomer Alexander Zaitsev’s transmission of pictorial and musical messages from the Evpatoria radio telescope in the Ukraine.

sources: interstellarmessage, seti.org