conventional radio astronomy observations. SERENDIP is currently piggybacking
on the 1,000-foot dish at <A HREF="http://www.naic.edu/">Arecibo Observatory
</A> in Puerto Rico, the largest radio telescope in the world.<P>
SERENDIP is dedicated to providing an answer to the age-old question <I>"Are
we alone?"</I><P>
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<A NAME="rationale"><H2>Rationale for radio SETI</H2>
Radio is the best and perhaps only chance we have at interstellar
communication, considering the distances involved. Radio waves, like all
electromagnetic (EM) radiation, travel at the speed of light, 300,000
kilometers per second. This is the fastest velocity possible, and yet even
Proxima Centauri, the closest star to our own sun, is far enough away that
light takes approximately four years to make the journey. Most stars are much
further away.<P>
In contrast to the speed of light, the fastest space vehicle we have with
current technology travels about 25,000 miles per hour, or about 4 kilometers
per second. At such speeds, it would take a rocket 300,000 years to reach our
nearest neighbor. SETI researchers must be patient by nature, but such a wait
is too much to ask.<P>
Radio waves are thought to be the electromagnetic medium of choice for
interstellar communication because the radio wavelengths are relatively free
of the absorption and noise that plagues other areas of the spectrum. Radio,
visible light, and the near infrared are the only EM radiation frequencies
able to penetrate the earth's atmosphere, and of the three, radio is not as
easily absorbed by interstellar gas and dust. In addition, stars are generally
quiet (or dim) in the radio wavelengths. This makes radio a natural candidate
for a deliberate beacon by an advanced civilization, or for interstellar
communications between civilizations.<P>
Besides deliberate interstellar transmissions, other civilizations could
display radio "leakage," or unintentional transmissions beyond their own
planets. As a matter of fact, nearly all of the artificial electromagnetic
radiation emitted from the earth is in the radio spectrum. Technological
civilizations within about a 50 light-year radius of the solar system could
now be watching first-run broadcasts of "I Love Lucy" and "The Honeymooners."
By the same token, SERENDIP researchers may one day serendipitously pick up
the Tau Ceti equivalent of terrestrial TV shows.<P>
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<A NAME="description"><H2>Description of the SERENDIP project</H2>
<H3><A HREF="ao_full.gif"><IMG SRC="ao_full.thumb.gif" ALIGN=top ALT=[Arecibo Image]>Arecibo Observatory</A> plays host to the SERENDIP instrument</H3>
<BR>
Piggybacking makes SERENDIP extremely cost-effective and allows it to run
full-time on Arecibo. The observatory houses the SERENDIP III spectrum
analyzer, which examines 4.2 million channels every 1.7 seconds in a
12 MHz-wide band centered at 429 MHz. This is only a small piece of the EM
spectrum, but it is by far the largest segment ever examined so
comprehensively. The SERENDIP instrument stores signals that peak
significantly above the background noise.<P>
On a weekly basis, this data is transferred across the Internet to the
SERENDIP lab at Berkeley. There researchers run the data through a series of
algorithms designed to reject radio frequency interference and detect signals
that have some possibility of being both artificial and extraterrestrial.<P>
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<A NAME="results"><H2>Current results</H2>
The 4 year SERENDIP III sky survey at Arecibo Observatory has recently been
completed,
logging a total of 10,000 hours of observation time. The project has observed 93
percent of the sky visible from Arecibo at at least once, and has passed over
43 percent of the Arecibo sky at least 5 times. Along the way, SERENDIP
has probed more than 100 trillion radio channels at very high sensitivity.<P>
Final SERENDIP III data analysis is currently under way.
So far, no signal has been so amazing that it sent SERENDIP researchers
rushing to Arecibo seeking dedicated telescope time, but the entire run of
data is getting a fresh look. When all of the data are
considered together, some candidates, such as those in which strong signals
recur several times, become more interesting. SERENDIP scientists then run
these candidates through additional algorithms, such as one to determine if
there is a likely star in the vicinity of the signal. If the same point in the
sky shows up on several different algorithms, it of course becomes much more
interesting.<P>
This page will be updated when the analysis is complete.
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<A NAME="history"><H2>History of SERENDIP</H2>
<H3><A HREF="hatcreek.gif"><IMG SRC="hatcreek.thumb.gif" ALIGN=╥top╙ ALT=[Hat Creek Image]>Hat Creek Observatory</A> is the first telescope that SERENDIP ever used</H3>
<BR>
SERENDIP has been in operation for 15 years, beginning with SERENDIP I in
1979, which consisted of a 100-channel spectrum analyzer at UC Berkeley's Hat
Creek Observatory.<P>
Since that time, SERENDIP has undergone a series of sequential improvements.
SERENDIP II, which ran from 1986 to 1988, was thousands of times more powerful
than its predecessor. The second-generation instrument was able to observe
65,000 channels per second on the 300-foot NRAO radio telescope and to a
lesser extent on four other high-quality telescopes around the world.<P>
SERENDIP III has been up and running at Arecibo since April 15, 1992, and
SERENDIP IV is due out in 1996.<P>
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<A NAME="next"><H2>What's next?</H2>
SERENDIP IV, due in the fall of 1996, will boost the project's number of channels
observed per second by a factor of 40, allowing researchers to collect 160
million channels worth of data every 1.7 seconds. SERENDIP IV, like SERENDIP
III, will be piggybacked to the Arecibo telescope. In addition, dedicated
telescope time will be used to look back at the most interesting candidates
from this and previous searches.<P>
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<A NAME="funding"><H2>Funding status</H2>
The search at UC Berkeley is extremely cost-effective, working on an annual
operating budget of $80,000. In the past, funding has been provided by a
combination of private donors and NASA, but with NASA SETI funding cut to
nothing by a budget-conscious Congress, SERENDIP is entirely dependent on
financial contributions and equipment donations from interested benefactors.<P>
<A HREF="http://planetary.org/tps">The Planetary Society</A>, a non-profit
organization headed by Carl Sagan, is the main financial sponsor of the SERENDIP
program.
Toshiba has been an especially generous equipment benefactor.
Harris Semiconductors, Microtec Research
and Intel have also provided equipment contributions.<P>
It is very rare for any project to get the prime telescope time that SERENDIP
has been able to get, but thanks to the piggybacking technique envisioned by
SERENDIP founder Stuart Bowyer, and the outstanding capabilities of the
SERENDIP instrument, SERENDIP has been able to remain a leader in world-class
SETI efforts. However, in order to ensure its future success, the project
needs donors. A small group of private donors called the Friends of SERENDIP
is headed by science and fiction writer Arthur C. Clarke and includes SETI
noteworthies such as Frank Drake and Carl Sagan, as well as Nobel Laureate
Glenn Seaborg. All contributions are administered by UC Berkeley.<P>
For more information about the Friends of SERENDIP, contact
