ET first contact 'within 20 years'

If intelligent life exists elsewhere in our galaxy, advances in computer processing power and radio telescope technology will ensure we detect their transmissions within two decades. That is the bold prediction from a leading light at the Search for Extraterrestrial Intelligence Institute in Mountain View, California.

Shostak, whose calculations will be published in a forthcoming edition of the space science journal Acta Astronautica, first estimated the number of alien civilisations in our galaxy that might currently be broadcasting radio signals.

Shostak admits that there are myriad uncertainties surrounding his prediction, but he defends the basis on which he made it. ."I have made this prediction using the assumptions adopted by the SETI research community itself."