SETI, the Search for ExtraTerrestrial Intelligence, is a serious undertaking. SETI@home is a combination of radio astronomy and distributed computing organized at the University of California, Berkeley, in which a radio receiver "piggybacks" on the radio telescope at Arecibo. The receiver records signals from whatever direction other users of the telescope have pointed it. The recordings are sent to Berkeley where they are broken into many pieces that are each small enough for computer analysis.
A typical 2GHz home PC may complete the analysis of a 9766 Hz wide, 107 second long slice of the recording in about 3-1/2 hours. Each 107 second recording at the telescope contains approximately 256 such slices. If the recorder is in operation continuously, it would produce many, many such slices each day and easily overwhelm even a modern supercomputer, even if U.C. - Berkeley had one for this purpose.
The computer analysis searches the usual random "cosmic noise" looking for "order", i.e. coherent signals that may signify an "intelligent source. According to the SETI website, the analysis makes use of a computationally intensive algorithm called "coherent integration" and "performs fast fourier transforms on the data, looking for strong signals at various combinations of frequency, bandwidth, and chirp rates." This is "serious computing."
Instead of trying to buy this much computer power, this SETI project taps the leftover capacity of thousands of volunteer participant's computers around the world. The project is aptly named, "SETI at home" or, sometimes, "SETI@home". There are over 5,000,000 volunteer accounts, of which more than 400,000 are still actively analyzing work from SETI. I have been volunteering my leftover computer time since October, 2001, and currently have two 2Ghz computers working for SETI. Some really serious participants have many computers working, and some have gained permission to have their company computer(s) doing analysis. Since the project began in 1999, approximately 1,700,000,000 analysis results have been received accounting for a total CPU time of about 2,200,000 years.
Of course, the activity is interesting as it is. However, some friendly competition between the various volunteers adds to the appeal. Teams have been formed based on some common thread of interest. Participants also compete as individuals, so they are interested in where they rank and how they are progressing. Since my education was in mathematics and my work experience has included extensive computer programming, I undertook a program that I have been running once a week to sample about 8000 participants status and show the various "benchmarks" and to project how they are moving. The results are a web page which show the tables and allows SETI participants to enter their own status and processing rates and get back an individualized projection of when they would reach their next benchmark.
SETI@home is about to make a major change in its software. A replacement program is being phased in which allow a variety of distributed computing applications to make use of the underlying concepts, and expands SETI@home to more telescopes.
One experience in participating with the SETI@home project stands out: I relate the saga of Great Aunt Millie here.
Originated: 12/26/2004
Latest update: 11/14/2008
Copyright 2004, 2008 © by Stan Pope. All rights reserved.