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Hunting for alien life?
26/10/2006 13:00 - (SA)
Paris - A new generation of ultra-powerful radio telescopes designed to peer into the origins of the Universe could also be used to look for any radio or TV emissions by extraterrestrial civilisations, New Scientist says.
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 E.T.'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 E.T. hunt, they first have to overcome the practical problem of discerning alien emissions from terrestrial interference, the report cautions.
- AFP
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