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Astrophysicists are reconsidering how they search for ET after 50 years of hearing nothing.
The Sound of Silence conference, being held at Arizona State University, is discussing how to improve the Search for Extraterrestrial Intelligence (SETI) programme.
"Have we been looking in the wrong place, at the wrong time, in the wrong way?" conference organiser Paul Davies said in the journal New Scientist.
One of the topics being discussed at the conference is whether Earth should do more talking, rather than listening.
"SETI's big mistake is that it's relying on ET to do all the heavy lifting," Princeton University astrophysicist Richard Gott said.
He said if the aliens had the same attitude as humans, "we'll all just be sitting round listening".
Australian astrophysicist Paul Davies believes the approach being undertaken by SETI researchers is too narrow, assuming aliens communicate the same way we do here on Earth.
"We're making a lot of assumptions about aliens based on human 20th century Western society," he said.
While broadening the search appears to be the way to go, long-time SETI researcher Dr Seth Shostack admits it would be a big task.
"If you want to hunt for buried treasure in Australia, sure, the best strategy is to take a shovel and dig up the whole country but, in practice, you just can't do that," he said.
The first SETI project, named Project Ozma, was conducted in 1960 by Cornell University astronomer Frank Drake.
Since than, several possible SETI finds have occurred, but none has been confirmed as being alien in nature.
Even home computers have been enlisted to help through the SETIhome project, which was launched eight years ago.
To date, the project has enlisted more than five million volunteers and 320,000 computers to process data received from radio telescopes around the world.
Last year, the SETI Institute switched on the first of 42 dishes that will make up the Allen Telescope Array, a facility dedicated to searching for extraterrestrial signals.
"In the next two years, we will have collected and analysed more new data than we have during the past 50 years," Dr Shostack said. He added that by 2028, the project will have surveyed more than one million star systems.
"If it remains silent after that, then that will be the time to rethink."
- AAP
