October 30, 1995. Copyright, 1995, Graphic News. All rights reserved

THE SEARCH CONTINUES
By Nicholas Booth, Science Editor

LONDON, October 30, Graphic News- Today, a giant step is taken in solving one of mankindÕs most enduring riddles Ð the search for signs of life elsewhere in the universe from radio transmissions. At the Oak Ridge Observatory near Harvard University in Massachusetts, a radio telescope will search the skies for unequivocal evidence for radio transmissions of alien origin. The telescope will be switched on during a ceremony today and spend the next five years looking for signs of life.

And, say astronomers involved with the Billion-channel Extra-Terrestrial Assay (BETA) project, they believe that they have the greatest ever chance of finding tell-tale signals from space. Their search is the astronomical equivalent of looking for a needle in a haystack. With an estimated 400 billion stars in our own galaxy, there is plenty of scope for intelligent lifeforms in space. The Harvard astronomers have had to make assumptions about how alien civilizations would wish to communicate with us.

In particular, they have assumed that our celestial brethren would know about a particularly quiet portion of the radio spectrum. This so-called ÔwaterholeÕ contains frequencies at which hydrogen Ð the most abundant atom in space Ð may be detected by radio telescopes. Any alien civilization broadcasting at this frequency would be particularly noticeable, rather like a lighthouseÕs beacon at night. 

Though there have been limited attempts at listening to the skies before, BETA will not only be able to hear likely alien signals more clearly but also compensate for the increasingly noisy background pollution of terrestrial signals. Though the ÔwaterholeÕ is relatively quiet, the encroachment of radio, cellular phones and radars has tended to swamp detection attempts. So BETA has a special detection system which scans terrestrial frequencies to eliminate them from any signal which looks alien in origin.

An earlier detector built by the Harvard team, known as META, scanned across a million channels. In 1993, they reported that they had found 37 interesting events Ð which were later found to be echoes within the electronics at their heart. BETA has improved electronics which will throw out such ÔglitchesÕ. The telescope also sweeps the sky in two separate beams. If an interesting signal is detected by one, it will have to be seen by the other to confirm it is extraterrestrial in origin. A new innovation is that when an interesting signal is seen, the telescope will automatically track it.

Sadly, official programmes to search for extraterrestrial intelligence have always been controversial. In 1993, NASA was forced by Congress to abandon its own search due to costs and a lack of appreciation of what they were trying to do. Funding for the BETA project has come from private grants and the Planetary Society, the worldÕs largest space interest group. BETA will scan the whole of the sky repeatedly over the next five years and will cost a total of $250,000.

Sources: The Planetary Society, Harvard University.