Saturday, October 30, 2010

The Arecibo Message and the search for extraterrestrial life

In 1974, mankind put forth its first attempt at communication with extraterrestrial intelligence (CETI). The effort consisted of a message beamed toward the star cluster M13 by the Arecibo radio telescope. This star cluster is the most prominent globular cluster in the northern half of the sky, and happens to lie in the constellation, Hercules. It spans well over 150 light-years, although the bulk of its over one million stars are concentrated into a core region with a diameter of about 100 light-years.

The Arecibo message consists of a string of 1679 binary digits that can be arranged into 73 rows and 23 columns (prime number multiples of 1679) to represent a picture describing human life on Earth. The uppermost portion of the message establishes that the number system on Earth is binary through a display of dots in formations one through ten, reading right to left. Beneath this appears the atomic numbers for the main biological elements: carbon, hydrogen, oxygen, nitrogen, and phosphorous, beneath which is a model of the chemical structure of DNA. The remaining portion of the message addresses the appearance, size, and number of human beings, as well as our location within our solar system.

Realistically, over the course of its 25,000-year-long journey, its likely that the Arecibo Message will be degraded beyond recognition by its interaction with cosmic dust and particles in the interstellar medium. With the loss of even a few bits of information, the signal will most likely be rendered undecipherable, however, a much larger duplicate message was sent on the 2001 Encounter Mission to address this problem.

The search for extraterrestrial life (SETI) initially began with microwave observation, and has just recently been expanded to include an optical search for extraterrestrial laser pulses. The basic strategy first involves the search for an indicator – a focused radio beam, a brilliant pinpoint of light – that is identifiable as intelligently controlled rather than a purely natural phenomenon (pulsars or quasars) or a human artifact (unexpected transmission from a “lost” satellite). However, the conformation that so many SETI scientists base their career upon could occur today, tomorrow, or never. A thorough search really depends on the exact magnitude of space, the number of technologically advanced civilizations that coincide with ours, as well as the search rate.

In searching for extraterrestrial life, some researchers probe galaxies beyond ours; however, most searches are limited to subsets of the billions of stars within our own galaxy. Additionally, of the searches that are performed, researchers either use an “all sky survey” mentality, which involves an encompassing but superficial look at unselected stars or a “targeted” search which is based on a closer inspections of the five to ten percent of stars that are believed to be promising hosts for life-bearing planets. With the advent of newer, more advanced, technologies, the search for extraterrestrial life by astronomers is looking more and more promising.

What I find to be a particularly interesting aspect of SETI today are the often-overlooked cultural, intellectual, and emotional factors that shape the search as well as the mindsets of the searchers. These factors bring an anthropological, psychological, sociological, as well as historical aspect to the discovery of extraterrestrial life that could help outline interstellar communications that can be understood in cultures that are radically different from our own. Specifically, anthropology (including archaeology and linguistics) along with psychology and cognitive science could be used to decrypt and interpret any message that we may intercept. Then, social psychologists and communications specialists could be used to facilitate the orderly dissemination of news to the public. The understanding of the media and mass communications, organizational functioning, social and psychological influences on attitude formation and change, as well as rumor control can make a huge difference when presenting information to the public. The way in which the information is presented to the public plays a huge role in their response, thus an understanding of human reactions is imperative when it comes to SETI discoveries. It seems like this would be an incredibly difficult task for these specialists appeal to the interests, knowledge, and beliefs of not just one or two nations or regions, but rather the entire human race though. The way that our cultures and societies have diverged in our time on Earth has made it incredibly difficult for these specialists to make this information culturally relevant and available to everyone – as all humans deserve to know if we are not alone in our universe.

1 comment:

  1. I mentioned this in my blog today, but when I was listening to Jeffrey Carver yesterday I was thinking about how similar SETI is to science fiction. It seems to me that many astrobiologists would regard much of science fiction as unfeasible, however, SETI seems just as realistic. We are assuming that aliens would be soooo similar to us as to have the technology to detect our message, have same cognitive abilities as to be able to decode our message, and lastly to care at all.