
   ET - we're looking for you



      The possible existence of life in space has long been the

     subject of wild speculation. Tomorrow, however, sees the launch of

     the first formal hunt for life when a radio telescope in Australia

     starts recording signals from deep space. Peter Pockley reports

     from Sydney







   THE FIRST concerted exploration of the cosmos for signs of alien life

   begins this week. For humankind, the outcome could be either momentous

   or a monumental flop. A team of American astronomers has just taken

   over the largest radio telescope in the southern hemisphere and

   selected the first star to be studied when the hunt began yesterday.



   For Dr Jill Tarter, this marked the start of a quest that has

   motivated her research for 20 years since she was a post-doctoral

   student: the search for extra-terrestrial intelligence (or SETI).



   This is no amateur probe into the universe by a bunch of space freaks.

   The 64-metre radio telescope at Parkes in New South Wales, 300 km west

   of Sydney, has been handed over by Australia's national research

   agency to Dr Tarter's team of scientists and engineers for their sole

   use in the next five months.



   Project Phoenix began at 11 am, when the giant dish wheeled across the

   sky and lock on to signals from nu Phoenicis, a star in the

   constellation Phoenix. Altogether, the project will systematically

   study 212 stars visible only from the southern hemisphere.



    'The most important question astronomers have to seek an answer to'



   The enthusiastic Dr Tarter is undeterred by the possibility of

   failure. She justified the multi-million dollar quest: "I find it the

   most important question astronomers have to seek an answer to. It

   affects everyone on Earth." Australian team leader Dr Kelvin

   Wellington said: "It's wonderful to be involved."



   The bulk of the US $7.3 million raised so far for Project Phoenix has

   come from co-founders of successful computer companies in Silicon

   Valley where the SETI Institute is based - Bill Hewlett and David

   Packard (Hewlett Packard), Gordon Moore (Intel Corporation) and Paul

   Allen (Microsoft). Many individuals have given small amounts,

   including science-fiction writer Arthur C. Clarke.



   The candidate stars have been selected for the search from Parkes as

   they can be seen only from the southern hemisphere and are roughly the

   age and temperature of the Sun, which the SETI astronomers believe

   will give the best chance of some having planetary systems.



   All stars in the universe naturally send out radiation generated by

   the intense turmoil within their hyper-hot gases. Just as in our solar

   system, life could not exist on the stars themselves, but on cool

   planets like the Earth which are likely to be orbiting some of the

   target stars.



   SETI astronomer Dr Seth Shostak explained the team's strategy: "The

   search will include the star nearest to Earth, the triple alpha

   Centauri (4.5 light years away) and other stars out to 150 light years

   away in our own galaxy (the Milky Way) which are old enough to have

   cooled to the Sun's temperature.



    Each star will be studied in two billion different frequencies



   "We'll have a look at the centre of the galaxy, roughly 25,000 light

   years away, in case an advanced civilisation has placed a radio beacon

   there. We may also take a look at tau Ceti, one of two stars first

   studied by Frank Drake from the USA for extra-terrestrial life,

   unsuccessfully, in 1960."



   Project Phoenix is looking for signs of highly intelligent

   civilisations which, in times past, have developed technologies akin

   to, or in advance of, our own. These would be indicated by precisely

   controlled radio signals which stand out from the more random natural

   radiation of parent stars.



   All the "ifs" and "coulds" about the existence of other intelligent

   life will remain in the realm of conjecture (critics of the project

   say fantasy) until evidence is obtained which stands up to scrutiny.

   That is why the scientists are being extra careful in how they collect

   the billions of signals which will arrive naturally at Parkes.



   Each star will be studied for half a day in two billion different

   frequencies. (The system will automatically sample 29 million channels

   at a time, scanning from one to three gigahertz, a range on which

   there is little interference from events in the cosmic background.)



   Interference from local earth-bound transmissions is a more serious

   problem. Dr Tarter said computers have been programmed to eliminate

   the widespread electronic garbage caused by cellular telephones,

   satellite transmissions and remote controllers for car locks and

   garage doors.



    Scientific caution will temper the temptation to go public prematurely





   Each day, Dr Wellington expects about a dozen signals to elude these

   electronic "gate-keepers" and to stand out, because of precise

   frequencies, as candidates for further study.



   Then a second, smaller radio telescope, controlled remotely at Mopra,

   200 km north of Parkes, will be brought into play. This can check

   whether a signal originated from something mundane, such as the local

   radio station.



   Because the two dishes are so far apart, any Earth-originated

   interference received at one can be cancelled out by the other.

   Corrections will also be applied for the rotation of the Earth and the

   rate of drift of the star across the cosmos. If, after passing checks

   from both dishes, a signal still stands out as "promising", a bell

   will ring and screens flash at Parkes. This is when the adrenalin will

   flow as observers stop the automated scanning and focus on making

   detailed measurements of the signal from the star in question.



   Dr Tarter expects the whole process to this point, conducted in "real

   time", to take about five minutes before what she describes as

   "carbon-based intelligence" (meaning the human brain) takes over.



   Although Dr Wellington acknowledges that the team (which includes 13

   astronomers, four of them Australian) will be under immense pressure

   from the media to make announcements, scientific caution will temper

   the temptation to go public prematurely.



    Scientists aware of panic Orson Welles created



   "We shall have to call on telescopes in other countries to verify our

   findings independently," he said. "But, since there are few radio

   dishes elsewhere in the southern hemisphere where the stars we are

   studying can be seen, seeking confirmation may take some time. We may

   need to ask Nasa if they can use their satellite tracking dish at

   Tidbinbilla near Canberra."



   The scientists are all too aware of the alarm created in the United

   States in 1938 by Orson Welles's convincing radio production of War of

   the Worlds. If successful, the team in Australia has agreed to

   minimise possible panic with a "declaration of principles".



   Other astronomers will be told first of a positive discovery. If

   confirmed, the secretary-general of the United Nations will be

   notified for announcement to the world.



   No reply will be transmitted without global consensus. By then, we

   shall all know that we are not alone in the Universe - and science

   will have presented theologians with another almighty question to

   explain.





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