Daily Mail, By DAILY MAIL REPORTER, 21st July 2010
Maybe they've been telling us what they had for dinner. Or perhaps they've just been trying to say hello.
But scientists today claimed that aliens may be using a cosmic version of Twitter to contact us - and we have been missing their 'tweets'.
ET is more likely to be sending out short, directed messages than continuous signals beamed in all directions, say experts.
'This approach is more like Twitter and less like War and Peace,' said Californian physicist Dr James Benford, president of Microwave Sciences Inc.
He and twin brother Gregory, an astrophysicist at the University of California, Irvine, looked at the Search for Extraterrestrial Intelligence (Seti) from the aliens' point of view.
The famous Lovell Telescope at Jodrell Bank in Macclesfield. Scientists believe that we could be listening out for the wrong signals
They concluded that Seti scientists may have been taking the wrong approach for the past five decades.
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Up to now the strategy adopted has involved listening out for unusual blips or bleeps from targeted nearby stars.
Despite 50 years of searching, no-one has yet been able to come up with evidence of an extraterrestrial signal. However, many scientists are convinced we cannot be alone in the universe.
'Whatever the life form, evolution selects for economy of resources,' said Gregory Benford. 'Broadcasting is expensive, and transmitting signals across light years would require considerable resources.'
Writing in the journal Astrobiology, the Benfords' claim that an alien civilisation would strive to reduce costs, limit waste and make its signalling technology efficient.
They propose that ETs' signals would not be blasted out in all directions but pulsed and narrowly directed in the one to 10 gigahertz broadband signal range.
Seti has been focusing its receivers on the wrong kind of signals, and also looking in the wrong direction, they claim.
Rather than pointing their antennae at nearby stars, scientists should be aiming at the centre of our galaxy, the Milky Way, say the Benfords.
'The stars there are a billion years older than our Sun, which suggests a greater possibility of contact with an advanced civilisation than does pointing Seti receivers outward to the newer and less crowded edge of our galaxy,' said Gregory Benford.
'Will searching for distant messages work? Is there intelligent life out there? The Seti effort is worth continuing, but our common-sense beacons approach seems more likely to a answer those questions.'
THE 'WOW' SIGNAL
- On August 15, 1977, the night before Elvis Presley died, a telescope in Ohio picked up a remarkable signal.
It lasted 72 seconds and was dubbed the 'Wow' signal because of the scrawled message of disbelief next to the printout.
The signal came from a blank patch of the sky somewhere in the constellation of Sagittarius and was exactly at the frequency at which engineers had been hoping to find messages from aliens.
No one has been able to explain it and it has never been heard since.
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