such as "Introduction", "Conclusion"..etc
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The SETI Institute predicts that we'll detect an extraterrestrial
transmission within twenty years. If that turns out to be true, it'll
probably be the folks at UC Berkeley's Hat Creek radio observatory who
will have heard the call. Right now, the Allen Telescope Array of more
than three-hundred dishes is under construction at Hat Creek five hours
north of San Francisco. Within a year, the first thirty dishes will be
operational, forming the basis of a giant ear that listens for
intelligent beings in space while simultaneously gathering data for
groundbreaking astronomy research.
William "Jack" Welch, UC Berkeley professor of electrical
engineering and astronomy, has been a driving force in the design and
construction of the Allen Telescope Array (ATA) since the project first
got off the ground five years ago as a joint effort between UC Berkeley
and the SETI Institute. Named for major donor Paul Allen, co-founder of
Microsoft, the array will eventually consist of 350 6.1-meter radio
dishes electronically networked together into a radio telescope with
unprecedented sensitivity. Precisely distributed across 2.6-acres on
the Hat Creek grounds, the combined dishes will have far greater
sensitivity than much more expensive 100-meter telescopes.
The SETI project scours millions of radio channels for narrow-band
signals, indicative of intelligent origin. It's like listening for a
station as you twist your car radio's tuning knob past all the static.
Until now, SETI has used limited time from myriad radio telescopes
around the world, limiting the number of stars that can be observed.
However, the ATA will be dedicated to the project, speeding up the SETI
search by a factor of 100. Meanwhile, the unique design of the system
enables astronomers to monitor a huge range of wavelengths to observe
other cosmic phenomena simultaneously with the SETI search.
"SETI is admittedly a long-shot," says Welch, holder of UC
Berkeley's first Chair in the Search for Extraterrestrial Intelligence.
"I don't have the patience to do only that, so it appeals to me to have
a steady flow of other data for us to study as well."
For example, Welch and his colleagues will use the array to make a
cosmological map of atomic hydrogen, the most abundant element we know
of. Indeed, the visible universe may be composed of up to
ninety-percent hydrogen. Determining its spatial distribution in nearby
galaxies could provide insight into the evolution of the cosmos and the
mysteries of dark matter.
"We'll be able to look halfway back to the beginning of the
universe," Welch says. "The ability to observe that far back into time
is limited right now."
To crank up the telescope's sensitivity, Welch and his colleagues
devised a bit of ingenious antenna technology. In traditional
pyramid-shaped antennas like those used in the ATA, the signal is
picked up at the tip of the structure, called the feed, and runs down
wires to the receiver. The problem, Welch explains, is that much of the
signal gets lost along the way. To keep the signal as pure as possible,
the Berkeley researchers shoehorned the receiver components inside the
"It's just one new wrinkle for technology that was originally
developed in the 1950s, but it enables our feed to essentially have no
limitation on bandwidth," Welch says.
Right now, just three prototype dishes are being put through their
paces at Hat Creek. In the next few months though, the researchers will
install more than two-dozen others, nearly one dish a day. By Summer,
Welch hopes this first small array will be scanning stars many
light-years away. Whether ET is intelligent enough to call remains to
be seen, or rather heard, but Welch is convinced that there's something
"The recent discovery of planets around many nearby stars is a
strong argument that our solar system isn't really unique at all," he
says. "That in itself makes it almost certain that there are nearby
planets with some kind of life on it."
University Of California, Berkeley. January 2005.
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