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Hunt for alien life turns to ET-TV
Paris -
A new generation of ultra-powerful radio telescopes designed to peer
into the origins of the Universe could reportedly also be used to look
for any radio or TV emissions by extraterrestrial civilisations.
According to the New Scientist, TV
and radio broadcasts are in the 50-400 megahertz range, which overlaps
with the frequency range of between tens and hundreds of megahertz
made by radio waves from hydrogen atoms forged in the early Universe.
Harvard University astrophysicists
Abraham Loeb and Matias Zaldarriaga suggest that tell-tale spikes in
the energy spectrum which are made by TV and radio broadcasts could be
discernible to telescopes such as the Low-Frequency Array (LOFAR) now
being built in the Netherlands.
These spikes, if they are ever picked
up, could be used to unlock key information from any alien world, the
British science weekly says in next Saturday's issue.
As a planet orbits a star, its
distance from Earth changes, which would cause a Doppler shift, or
widening, in the frequency range of ET's emissions.
Loeb and Zaldarriaga believe this
shift will make it possible to deduce the shape of the orbit, the
planet's tilt and distance from the star -- which in turn will enable
scientists to make a stab at calculating the planet's surface
temperature and whether it could have liquid water.
As many as 100 million stars with
planets lie within a box of 1,000 light years from Earth from which
such radio leakage is possible, they calculate.
If LOFAR and other big telescopes
still in the planning phase are turned to the ET hunt, they first have
to overcome the practical problem of discerning alien emissions from
terrestrial interference, the report cautions. --
Agence France Press
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