Later on Oprah

The project of monitoring the heavens for radio broadcasts assumes that a technological civilization would have invented something that produces intelligible signals in the radio wavelengths. There is no need to assume, however, that the distant civilization actually wants to communicate and is intentionally broadcasting to other worlds. After all, we on the earth have been broadcasting since the early twentieth century and have been doing so intensively for more than 60 years.

Close Encounter

Monitoring the vast heavens for artificial extraterrestrial broadcasts is a daunting task-akin to looking for a needle in a haystack. Where should we look? What frequencies should we monitor? How strong will the signal be? Will it be continuous or intermittent? Will it drift? Will it change frequency? Will it even be recognizable to us?

At the very least, radio searches are time- and equipment-intensive. Frank Drake conducted the first searches in 1960, using the 85-foot antenna at the National Radio Astronomy Observatory in Green Bank, West Virginia. He called his endeavor Project Ozma, after the queen of the land of Oz. This search ultimately developed into Project SETI (Search for Extra-Terrestrial Intelligence), which, despite losing its Congressional funding, remains the most important sponsor of search efforts.

The SETI Institute is a private, non-profit group based in Mountainview, California. When NASA search funding was cut in 1993, SETI consolidated much of its effort into Project Phoenix (risen, like the mythical bird, from the ashes of the funding cut), a program that began in 1995 and that monitors 28 million channels simultaneously. SETI hopes eventually to monitor two billion channels for each of some 1,000 nearby stars. Computer software alerts astronomers to any unusual, repeating signals. So far, no positive findings have been obtained.

Want to do your bit for the Search for Extra-Terrestrial Intelligence (SETI)? Download a screensaver that just might find ET. You never know. It uses cycles on your computer (when not in use) to process one of the largest datasets mankind has ever assembled. (www.seti-inst.edu/science/setiathome.html.)

And if you just want to check the current status of SETI, go to www.seti-inst.edu. The SETI Institute recently received a large financial boost from Microsoft cofounders Paul Allen and Nathan Myhrvold, who have committed $25 million to the construction of a radio telescope array dedicated to the SETI search. Up to this point, searches have depended on cadging time on existing telescopes. The proposed Allen Telescope Array will be dedicated to the SETI project around the clock.

While radio signals at longer wavelengths do not penetrate beyond our atmosphere, those in the higher frequencies, FM radio and television, are emitted into space. We don't intend this to happen, but it is an inevitable by-product of our technological

Astro Byte

Radio signals? Why not an optical laser sent out into space? Because the dust in the plane of our Galaxy absorbs optical photons very well. So an optical-frequency beacon would not get very far. Radio waves, on the other hand, pass through the dust as if it weren't there. We (and our neighbors) cast a wider net in radio waves.

Astro Byte

Radio signals? Why not an optical laser sent out into space? Because the dust in the plane of our Galaxy absorbs optical photons very well. So an optical-frequency beacon would not get very far. Radio waves, on the other hand, pass through the dust as if it weren't there. We (and our neighbors) cast a wider net in radio waves.

The water hole is the span of the radio spectrum from 18 cm to 21 cm, which many researchers believe is the most likely wavelength on which extraterrestrial broadcasts would be made. The name is a little astronomical joke—the hydrogen (H) and hy-droxyl (OH) lines are both located in a quiet region of the radio spectrum, a region where there isn't a lot of background noise. Since H and OH add up to H2O (water), this dip in the spectrum is called the "water hole."

Star Words

The water hole is the span of the radio spectrum from 18 cm to 21 cm, which many researchers believe is the most likely wavelength on which extraterrestrial broadcasts would be made. The name is a little astronomical joke—the hydrogen (H) and hy-droxyl (OH) lines are both located in a quiet region of the radio spectrum, a region where there isn't a lot of background noise. Since H and OH add up to H2O (water), this dip in the spectrum is called the "water hole."

civilization. Perhaps some other civilization is producing a similar by-product. Our first glimpse of another civilization might be the equivalent of its sitcoms, advertising, and televangelists. Yet we keep on listening.

Telescopes Mastery

Telescopes Mastery

Through this ebook, you are going to learn what you will need to know all about the telescopes that can provide a fun and rewarding hobby for you and your family!

Get My Free Ebook


Post a comment