Anyone with a computer and an Internet connection can join a worldwide search for intelligent life in space from Monday.

Radio astronomer Ian Morrison: "You log on to the site, download a screensaver and leave it to your computer"

The Seti@home project is a "grand experiment" allowing thousands of volunteers to download a screensaver and a chunk of data from the world's largest radio telescope.

When your computer is idle the program searches the data for any indication of intelligence.

Scientists believe that the best way to find life in space is to look for radio signals. Since 1960 there have been about 70 unsuccessful searches.

Seti is stepping up its hunt for alien life

The project has a list of nearly 400,000 people from 96 countries waiting for the final version of the software. From Monday it is available for download from the Seti@home Website.

As the computer works on the data, the screen displays a three-dimensional graph charting the signal analysis.

Participants also can view maps showing where the Seti@home project is searching and who is taking part in the project.

After the computer is finished, it sends the results back to Seti@home scientists at the University of California at Berkeley and grabs another chunk of data.

"This project lets us do Seti a lot, lot faster, with 10 times more sensitivity and exploring more thoroughly the spectrum of radio frequencies we scan," said Seti@home's Dan Werthimer.

Louis Friedman of the Planetary Society, which is a principal sponsor for the project, said: "Never before has there been an opportunity for anyone, anywhere in the world, to join the scientific search for intelligent beings elsewhere in our universe."

'Grand experiment'

He added: "This is a grand experiment - in science, in technology and in society - a global co-operative effort at the frontiers of knowledge.

"Seti@home is a way of harnessing all the idle computers to increase our computing capacity and our chance of finding extraterrestrials."

The radio data is broken down into small chunks - a 10 kilohertz range of wavelengths in a strip of sky visible from the Arecibo telescope in Puerto Rico - through which the screensaver program can search for patterns.

The data downloaded to each desktop computer takes up only about 250k of computer memory, though the computer must have 32mb of RAM to run the software.