SEATTLE -- On
Wednesday, January 10, here at the American Astronomical Society Meeting, theorist Dr. Avi Loeb from Harvard Smithsonian Center for
Astrophysics led a press conference on the search for ET. "Soon, we may be
eavesdropping on signals from Galactic civilizations," said Loeb. "This is the
first time in history that humans will be capable of finding a civilization
like ours among the stars." Loeb asserts that the proposed search will find "leakage"
from transmissions equivalent to our broadcast television or military radars.
SETI Institute's Project Phoenix and UC Berkeley's SERENDIP have both had the
technical capability to detect intentional signals--beamed at Earth--with the
equivalent power to military radars. Loeb's search would expand the frequency
range over which searches are conducted.
Loeb and
his co-author Matias Zaldarriaga (CfA) suggest looking for accidental leakage
from an alien civilization. They point out that the new Mileura Wide-Field
Array's Low Frequency Demonstrator (MWA-LFD), which is designed to study
frequencies of 80-300 Megahertz, will pick up the same frequencies used by
Earth technologies. On Earth, military radars are the most powerful broadcast
sources, followed by television and FM radio. If similar broadcast sources
exist on other planets, facilities like MWA-LFD might detect them. A SETI
program at the MWA-LFD would complement other SETI projects. It will observe a
larger area of the sky over a longer period of time and in a different
frequency range.
"The
MWA-LFD is a science instrument intended to study the distant, young universe,"
explained Zaldarriaga. "But by piggybacking onto its normal observations, SETI
researchers could use it to look for E.T. civilizations." Loeb and Zaldarriaga
calculate that by staring at the sky for a month, the MWA-LFD could detect
Earth-like radio signals from a distance of up to 30 light-years, which would
encompass approximately 1,000 stars. More powerful broadcasts could be detected
to even greater distances. Future observatories like the Square Kilometer Array
could detect Earth-like broadcasts from 10 times farther away, which would
encompass 100 million stars.
Dr. Peter
Backus, Research Scientist at SETI Institute also spoke at the press
conference. He stated that the MDA-LFD represents a good example of the power
of the new generation of radio telescopes. Taking advantage of advances in
technology, these telescopes are more powerful and flexible than the
traditional, large radio telescopes. Using this same design model, "large N,
small D" (a large number of small diameter dishes) the Allen Telescope Array
(ATA) will ultimately have 350 dishes, each only 6 meters across. The
combination of these dishes will have the equivalent sensitivity of the Very
Large Array in New Mexico and the Green Bank Telescope in West Virginia. Using
programmable electronics, the signals from the 350 dishes can be combined to
form up to 16 virtual antennas, each making independent observations. At the
same time, other electronics can image an area of the sky at two different
frequencies. The ATA will expand the search to higher frequencies that have far
less interference and background noise than the lower frequencies that will be
observed by the MWA-LFD.
Backus
feels that this proposed low-frequency search is a good first step in exploring
the lower frequencies for leakage or non-intentional signals. The unknown
properties of such extraterrestrial transmissions will continue to provide
challenges for low frequency searches. He looks forward to the outcome of this
new observing project with the MWA-LFD.
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