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NOVA scienceNOW: The Search for ET
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Program Overview
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Astronomers report on the search for extraterrestrial intelligence
(SETI). They also describe how this search has changed over the past
40 years and how it has recently accelerated thanks to new search
tools.
This NOVA scienceNOW segment:
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reports that astronomers have been searching for
extraterrestrial intelligence in the Milky Way galaxy for about
40 years.
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acknowledges that only a small fraction of the cosmos has been
searched and, to date, no extraterrestrial life has been found.
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relates searching for alien signals to looking for a clear
signal on the radio dial. In space, objects such as galaxies,
pulsars, and quasars emit radiation across the full
electromagnetic spectrum. Against this static-like "background
noise," a narrowly focused signal in one band of the
electromagnetic spectrum would likely signal the presence of an
alien civilization.
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theorizes that any technically advanced civilization would send
electromagnetic signals into space, either deliberately or
unintentionally. For example, electromagnetic waves from
Earth-based television and radio broadcasts have been leaking
into space for over 80 years and will have reached any planet
within 80 light-years of Earth.
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mentions that in the 1990s, NASA funded an extraterrestrial
search facility based at the Arecibo radio telescope in Puerto
Rico. This SETI funding was eliminated in 1993.
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reports that there is a SETI renaissance thanks to a large grant
from Paul Allen, a founder of Microsoft. New SETI components
include the Allen Telescope Array, one of the largest, most
sensitive radio telescopes in the world.
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states that the scope of the search for extraterrestrial life is
nearly impossible to comprehend. Our galaxy alone has about 300
million stars, and beyond it lie over 100 billion more galaxies.
Taping Rights: Can be used up to one year after the program
is taped off the air.
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