The SETI Project

Last updated: 30/1/01 - entire text, Optical SETI

In How to find ET life we discussed the various methods that could be used; straightforward interplanetary probes and possibly even interstellar probes, or the SETI project.

The SETI project stands for the Search for Extra-Terrestrial Intelligence. While SETI has been portrayed as simply searching the airwaves for radio signals from other stars, it also conducts a great deal of other research.

It's important not to mistake the whole SETI project with the SETI Institute. The SETI project is a catch-all term for every single experiment that is geared towards the search for extra-terrestrial intelligence. The SETI Institute is an actual non-profit organization that employs scientists to run various projects aimed at listening to other stars and to conduct research in helping the overall SETI effort. The 'listening to stars' part of the SETI Institute is called Project Pheonix, and of course is the institute's largest project.

		The Arecibo radio telescope in Puerto Rico. Arecibo is being used by both the SETI Insitute for Project Pheonix, and by the University of California, Berkeley, for their SERENDIP IV. Photo Courtesy David Parker/NAIC.

The sorts of research that the SETI Institute funds is all related, in one way or another, to Drake's Equation. To recap, Drake's Equation allows researchers to determine the number of intelligent extra-terrestrials in our galaxy that would be able to communicate with us.

Of course, it's not quite as simple as that. Drake's Equation only provides a framework for scientists - we still have to figure out the numbers to put in the equation.

For example, one of the components of Drake's Equation is F_l - the fraction of planets that are suitable for life on which life actually develops. Many of the projects at the SETI Institute are aimed at trying to narrow down a value for F_l, by looking at how life originated on Earth and how life might have originated on Mars in the past.

The Institute is also conducting research to find out which stars they should look at - if they can identify the types of stars that will produce solar systems with planets like ours, then they can narrow down their search. So far, the SETI Institute is conducting over 30 of these projects to narrow down the Drake's Equation values. Eventually they hope to be able to come up with ever more accurate estimates of how many extra-terrestrial civilizations there may be.

The SETI Institute is by far the most prominent SETI effort going on at the moment, being sponsored by a few major donors such as William Hewlett, David Packard, Gordon Moore, Paul Allen, and Barney Oliver, foundations and many individuals. However, as mentioned earlier, it is certainly not the only SETI effort.

		Hat Creek Observatory was the home for the original SERENDIP project, and is the future location for the new One Hectare Telescope. Courtesy Seth Shostak/SETI Institute.

Other major non-SETI Institute projects include SERENDIP IV, run by the University of California, Berkeley. The Planetary Society also operates Project Beta at Harvard University. Another well known project is the SETI@Home project, aimed at involving ordinary computer users in a massive distributed computing project that will analyze the data gathered by the Arecibo radio telescope.

SERENDIP stands for the Search for Extraterrestrial Radio Emissions from Nearby Developed Intelligence Populations. SERENDIP IV is the fourth instrument of the SERENDIP project and collects data by 'piggybacking' on top of the Arecibo radio telescope. The SERENDIP IV instrument is basically a 200 billion operations per second supercomputer that scans 168 million narrow (0.6 Hz) channels every 1.7 seconds for signals that are significantly 'louder' than the background static (like our radio tuning explanation).

The SERENDIP project began in 1979 at the University of California, Berkeley's Hat Creek Observatory , and has been running in one form or another since then. SERENDIP IV was installed at Arecibo on June 11th, 1997.

		The Rapid Prototype Array is a testbed for the technologies that will be used in the construction of the Allen Telescope Array. Photograph courtesy of Seth Shostak/SETI Institute.

The SERENDIP project director, Professor Dan Werthimer, also runs the SETI@Home project. We conducted an interview with Professor Werthimer about SETI@Home, the Allen Telescope Array and optical SETI.

Prof. Werthimer is also involved with the Allen Telescope Array (formerly called the 1hT, or One Hectare Telescope). The $26 million telescope is sponsored by Paul Allen and Nathan Myrhvold, both technologists from Microsoft, and could conceivably be made up of over 700 antennas of 4m diameter each, resulting in an instrument with the effective collecting area of 100 metres.

The Allen Telescope Array is a joint project between the University of California, Berkeley, and the SETI Institute, and will be dedicated towards listening for alien civilizations. To give an idea of exactly how effective the new array will be, it will be able to listen to up to one million nearby stars when it starts up in 2005 - several hundred times more than the SETI Institute's current Project Phoenix telescope can presently. Without a doubt, the ATA will be by far the most powerful instrument SETI researchers will have for the next decade.

A working prototype of the Allen Telescope Array has already been produced by the SETI Institute, called the Rapid Prototype Array.

Optical SETI (OSETI)

Listening to radiowaves isn't the only way in which SETI can be conducted - many SETI researchers have believed that alien civilizations might be sending out pulses of laser light encoded with information in an attempt to communicate with other stars, and so we need to watch out for them. Since 1998, scientists at Harvard University have been conducting a search for laser pulses from other stars using a 61 inch optical telescope and have taken over 20,000 observations.

Another project currently underway is situated at the COSETI Observatory (Columbus Observatory Optical SETI program) in Columbus, Ohio. COSETI has been operating using a smaller 10 inch aperture optical telescope and has been actively publicising and advocating the growth of OSETI methods alongside 'traditional' radiowave SETI methods.

In December 2000, Harvard University began the construction of a new 72 inch optical telescope sponsored by the Planetary Society, dedicated to an 'all-sky' optical SETI project. With 1024 ultrafast detectors that can detect pulses of light as short as a billionth of a second, the new telescope will be able to conduct a full-sky survey in 200 nights - this joint project is by far the most ambitious OSETI program yet initiated.

Scientists don't want to stop at merely watching for laser pulses - they want to send out their own, aimed at other stars that are likely to harbour habitable planets. According to the project leader of the new Harvard telescope, Professor Paul Horowitz, it is now possible to generate a beamed laser pulse that to the receiving civilization appears 5000 times brighter than our sun.